7566_chap02

MAINTAINABILITY OF FACILITIES - For Building Professionals© World Scientific Publishing Co. Pte. Ltd.http://www.worldscibooks.com/architecture/7566.html

CHAPTER 2

WET AREA

2.1. General

One of the building elements that demands high attention is internal wetareas. Internal wet areas are areas subjected to constant damp conditionswith alternating drying and wetting cycles. Although wet areas may onlyoccupy less than 10% of the gross floor area, the annual maintenance costfor wet area can range from 35% to 50% of the total maintenance costdepending on the type of facility [1].

Various systems and components such as waterproofing membrane,screed, architectural finishes, service pipes and sanitary fittings are usedin wet areas. In-situ construction and pre-cast technology have beenadopted to construct these units. These systems and components are madeup of numerous sub-components whose performances are depended onfor the overall structural, functional and aesthetic performance of thewhole system. The failure of any component may result in subsequentdefects surfacing in other components and ultimately bringing about thetotal failure of the entire wet area. It is hence crucial for the design, con-struction and maintenance of all components to be carried out soundly andwith due considerations to the likely impacts they would have on eachother and on the overall performance of the system [2].

2.2. Systems and Components Selection

The selection of primary components and systems such as waterproofingsystem, screed, tile and tile bedding, grout, paint and service pipesare mainly based on their serviceability so that they may continue to per-form their intended functions through their design life. Durability of these

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components should be checked under the real exposure conditions in wetareas. Compatibility among components is crucial.

Details of material durability, property etc. can be found in the“Material Manual” of the Maintainability Website (http://www.hpbc.bdg.nus.edu.sg/).

2.2.1. Waterproofing System

Waterproofing systems are applied over the substrates of wet area floorsand walls to improve the water-tightness of the wet area units. Water-tightness of wet areas relies mainly on the adequacy of waterproofing overpenetrations, projections and joints and how these discontinuities of thefloor and wall elements can achieve a “monolithic” structure. The deci-sion to select a specific waterproofing system should take intoconsideration the design of the substrate structure and area of coverage.

Generally, waterproofing systems can be classified into three types [3]:

(1) preformed membrane,(2) liquid-applied membrane, and(3) integral systems

Figure 2.1 shows the various classifications of waterproofing systems ofpreformed, liquid-applied and integral systems. Typical examples aregiven in Table 2.1.

Preformed membrane is often used for large areas such as roofs andbasements. Liquid-applied membrane is popular for small areas such aswet areas because:

(1) The membrane is seamless (no physical joints).(2) The membrane has good elongation and recovery properties to

accommodate substrate movements and to bridge cracks.(3) Of its unique built-in primer, it provides positive adhesion to both

base substrate and top wearing (screed) surface (i.e. screed can beapplied directly on membrane without debonding).

(4) Of its even adhesion to every part of the substrate.(5) It offers the flexibility of applying over the substrate.

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22 Maintainability of Facilities



(6) Of its continuity between (a) horizontal and vertical planes, (b) atabutments of joints and (c) around penetrations and projectionsoffering homogeneity to the whole system.

Integral systems are also becoming popular in these areas due to thier,easy application. They reduce the permeability of the concrete by intro-ducing water-reducing agents, pozzolanic products, organic binders orpore blocking additives.

Selection criteria of waterproofing system should include:

(1) Compatibility with other sub-components such as screed and tilebedding.

(2) Ease of application, especially at pipe penetration areas.(3) Elasticity and ability to bridge over cold joints and differing materials.(4) Good adhesion and cohesion strengths.(5) Ability to retain its adhesion and remain stable under extreme

fluctuations of temperature and moisture.(6) Ability to resist mechanical damage such as peeling, cracking and

rupture prior to screed finish.

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Wet Area 23

Fig. 2.1. Classification of waterproofing systems.



2.2.2. Screed

A screed is a layer of well-compacted material applied in situ to a struc-tural base or some other substrate and finished to a designated level [5, 6].Its functions include:

(1) to provide a smooth, flat surface to a correct level for bedding of tiles,(2) to serve as a protection for the waterproofing coating,(3) to provide falls to drain water off,(4) to accommodate service pipes.

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Table 2.1. Examples of different waterproofing systems [4].

Types of Systems Nature Examples

Preformed membrane Bituminous AsphaltBitumenModified bitumens

Nonbituminous Ethylene-copolymer bitumen (ECB)Polyvinyl chloride (PVC)Polyethylene (PE)Chlorinated polyethylene (CPE)Butyl rubberEthylene propylene diene (EPDM)NeoprenePolyisobutylene (PIB)Bentonite clays

Liquid-applied membrane Bituminous Bituminous modifiedNonbituminous Acrylic

EpoxyPolyurethane (PU)Polyisorene/rubberCementitiousSiliconHypalonNeoprene

Integral systems Crystalline waterproofingChemical admixturesWaterproof screeds



Wet systems are often used in the construction of wet areas includingmonolithic, bonded, unbonded, floating and proprietary screeds(Table 2.2) [7].

2.2.3. Tile

Man-made and natural tiles are popular finishing materials due to theirtested performance such as durability, cleanability and good appearance(Fig. 2.2) [8, 9].

2.2.3.1. Man-Made Tiles

There are typically two types of man-made tiles: ceramic and homoge-neous tiles.

Ceramic tiles can be classified into extruded tiles and dust pressed tiles.Extruded tiles are shaped in the plastic state in an extruder and the result-ing column cut into tiles of predetermined lengths. Dust-pressed tiles areformed from powder or small grains, shaped in moulds under high pres-sure before firing. The surfaces of these tiles are either glazed or unglazed

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Wet Area 25

Table 2.2. Various types of wet systems.

Types Definitions

Monolithic screed Screed which is laid on in-situ concrete base before it has(on green concrete) set (within 3 h of placing) is known as monolithic screed.

Bonded screed Also known as separate construction and bonding agent,(on hardened concrete/ it can be used to ensure maximum bond with the base.precast concrete)

Unbonded screed Unbonded construction is adopted when the screed is laid onthe damp proof membrane or when the concrete containswater repellent admixture.

Floating screed This type of screed is unbonded to concrete base and isdesigned as floating screed to accommodate heatingelements or sound insulation.

Proprietary floor screed Screeds that are basically denser and modified by inclusionof materials in emulsion form are known as proprietaryfloor screeds.



(Figs. 2.3a and 2.3b). Glazed tiles undergo an additional phase in the fir-ing process with a layer of liquid glass. A range of colors are achievableby mixing certain mineral elements, e.g. gold, silver, copper, cobalt, zinc.The nonporous layer of liquid glass makes the tile surface more stainresistant but less slip and scratch resistant. For flooring of wet areas,unglazed tiles are more suitable due to its better slip resistant.

Homogeneous tiles are obtained from very low water absorption ceramictiles that are dry pressed and produced by single firing. They are superior toordinary ceramic tiles as they are made of a single compact body mass andare virtually porous free with very low water absorption (1–3%). Unlikeceramic tiles, homogeneous tiles are uniform in color throughout the tilesand so when a homogenous tile cracks or is chipped, it will not expose anyindifferent color and is hence less noticeable. The surfaces of these tiles canbe polished, matt finished, rock finished or structured finished.

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Fig. 2.2. Classification of tiles.



Table 2.3 tabulates the basic properties of ceramic versus homoge-neous tiles.

2.2.3.2. Natural Stone Tiles

Granites and marbles are the more common types of natural stones usedin wet areas. Compared to marble, granite offers more regularity in colortone and texture. Its unique speckled and crystalline appearance distin-guishes granite from other natural stones (Fig. 2.4a). Marble is usuallyadorned for its “natural beauty look” due to its irregularities in veiningand color tone (Fig. 2.4b). Table 2.4 tabulates the basic properties ofgranite versus marble.

2.2.4. Tile Bedding

Bedding materials provide the bonding between tiles and substrates.Ordinary cement mortar with additives is commonly used in wet areas.These materials are normally characterized by their adhesive strength, opentime (allowable time for application) and deformability. The selection of thecorrect type of bedding material for tiling needs to be compatible with thetype of substrate, tile and the designed bedding thickness, to minimize con-sequences such as debonding, cracking and efflorescence [10].

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Wet Area 27

Fig. 2.3. (a) Glazed tiles and (b) unglazed tiles.

(b)

(a)



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Tabl

e 2.

3.Pr

oper

ties

of c

eram

ic ti

les

and

hom

ogen

eous

tile

s.

Pro

pert

ies

Cer

amic

Hom

ogen

eous

Size

/dim

ensi

on (

mm

)20

0×

200/

300

×30

0, w

ith to

lera

nce

in d

evia

tion

1–1.

5%.

Com

mon

ly a

vaila

ble

size

: 150

×15

0, 2

00×

200,

300

×30

0, 6

00×

600,

2–5

% a

llow

ance

, thi

ckne

ss

is 7

–9 m

m f

or f

loor

and

wal

l.

Con

stitu

ents

Cla

y ab

out 5

0–60

%, f

lint a

bout

30–

35%

and

C

lay,

fel

dspa

r an

d si

lica

sand

are

sie

ved

to a

feld

spar

abo

ut 1

0–15

%.

part

icle

siz

e of

onl

y 45

mic

rons

.

Wei

ght

Ran

ged

from

10

to 1

5kg

/m2

for

wal

l tile

s an

d 19

to 2

4kg

/m2

for

floo

r til

es.

Col

or f

astn

ess

Col

ors

in c

eram

ic ti

les

are

unaf

fect

ed a

nd w

ould

not

V

ario

us c

olor

s an

d te

xtur

es.

chan

ge o

r fa

de o

n ex

posu

re to

atm

osph

eric

T

he c

olor

and

bri

ghtn

ess

of h

omog

eneo

us ti

le is

cond

ition

s.un

affe

cted

whe

n ex

pose

d to

UV

light

.

Dir

t res

ista

nce

Bot

h do

not

ret

ain

dust

or

resi

dues

. Rou

tine

mai

nten

ance

, usu

ally

no

mor

e th

an w

ipin

g til

es w

ith a

dam

psp

onge

.

Fire

res

ista

nce

Bot

h ar

e co

mpl

etel

y fi

re-p

roof

at a

ny te

mpe

ratu

re. T

hey

will

not

bur

n or

fee

d a

fire

. The

ir s

urfa

ce w

ill n

ot g

ive

off

any

toxi

c ga

sses

or

fum

es d

urin

g a

fire

. In

addi

tion

to b

eing

fir

e-pr

oof,

tile

s ha

ve b

een

foun

d to

pro

vide

exce

llent

pro

tect

ion

for

stru

ctur

al s

urfa

ces

duri

ng f

ire.



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Wet Area 29

(b)

(a)

Fig. 2.4. (a) Granite and (b) marble.

Table 2.5 shows the properties of different tile beddings.Recommended compatibilities of types of bases, tiles and tile beddingsare shown in Tables 2.6 and 2.7.

2.2.5. Grout

Grout serves as a sealer for tile joints to prevent water seepage. Groutingmaterials should have good working characteristics, low shrinkage and goodadhesion properties to seal up tile joints. Commonly available grouts includecementitious, organic polymer-based compositions and epoxide resins.

Important performance parameters include:

(1) impermeability,(2) resistance to water, heat, cleaning agents, chemicals,(3) resistance to mold growth and bacteria,(4) resilience and compressibility,(5) resistance to high-pressure water cleaning,(6) compatibility of substrate and grouts.

Minimum standards that grouts should achieve for sustainability in wetareas are illustrated in Table 2.8.



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Tabl

e 2.

4.Pr

oper

ties

of g

rani

te a

nd m

arbl

e til

es.

Pro

pert

ies

Gra

nite

Mar

ble

Gro

upIg

neou

sM

etam

orph

ic

Min

eral

gro

upSi

liceo

usC

alca

reou

s

Wei

ght (

kg/m

3 )26

11–2

707

2651

–273

1

Com

posi

tion

Feld

spar

, qua

rtz

and

smal

l am

ount

s m

ica

Cal

cite

, dol

omite

or

a co

mbi

natio

n of

bot

h an

d ar

e th

e pr

imar

y m

iner

als

as b

elow

acce

ssor

y m

iner

als

actin

g as

col

orin

g ag

ents

.V

eini

ng m

iner

als

rang

e fr

om c

alci

te, q

uart

z an

d a

vari

ety

of o

ther

min

eral

s

Col

ors

Gra

nite

is f

ound

in m

ore

than

a h

undr

ed

Eve

ry c

olor

is p

ossi

ble

due

to th

e va

riab

ility

dist

inct

col

ors

with

var

ying

pat

tern

sof

acc

esso

ry m

iner

als

Fini

shes

Po

lishe

d, h

oned

, fla

med

, bus

h ha

mm

erPo

lishe

d, h

oned

Thi

ckne

ss

10–1

5m

m f

or in

tern

al w

all;

up to

20

mm

for

flo

or

Tre

atm

ent

It is

impo

rtan

t to

seal

the

ston

e to

ens

ure

it ca

n la

st to

its

max

imum

life

span

by

resi

stin

g sc

ratc

h,w

ater

pen

etra

tion,

sta

ins,

etc

. Thi

s is

usu

ally

don

e be

fore

inst

alla

tion

on th

e fi

ve s

ides

(fr

ont a

ndfo

ur s

ides

) of

the

indi

vidu

al c

ut-p

anel

, or

even

six

sid

es (

incl

udes

the

back

sid

e). W

hen

nece

ssar

y,so

me

trea

tmen

ts s

houl

d be

invo

lved

, suc

h as

col

or e

nhan

cer,

anti

slip

res

in, e

tc.

Har

dnes

s H

ard

Soft

/med

ium

/har

d

(Con

tinu

ed)



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Wet Area 31

Tabl

e 2.

4.(C

onti

nued

)

Pro

pert

ies

Gra

nite

Mar

ble

Mod

ulus

rup

ture

(M

N/m

2 )10

.27–

21.1

0 9.

2–18

Den

sity

(g/

cm3 )

2.5–

2.7

2.4–

2.8

MO

HS’

Scal

e5–

73–

5.5

Poro

sity

(%

)0.

24–2

.30.

6–2.

3

Wat

er a

bsor

ptio

n (%

)0.

05–0

.5

0.1–

0.6

Coe

ffic

ient

of

linea

r3.

7–6.

0 2.

7–5.

1ex

pans

ion

(/ºC

×10

–6)

Abr

asio

n re

sist

ance

(m

m)

0.68

–4.1

0.

25–2

.9

Com

pres

sive

str

engt

h (M

N/m

2 )10

7.56

–212

.37

62.4

6–12

2.64

Flex

ural

str

engt

h (M

Pa)

11–2

6 6.

15–2

1.4

Tend

enci

es

Abs

orbs

oils

and

oth

er li

quid

s. G

ener

ally

Abs

orbs

oils

and

oth

er li

quid

s. E

asily

scr

atch

ed.

not a

ffec

ted

by a

cidi

c fo

ods

and

drin

ks,

Aci

d se

nsiti

veho

wev

er, p

olis

hed

gran

ites

can

be e

tche

dby

hyd

rofl

uori

c ac

id a

nd c

once

ntra

ted

acid

s w

hich

are

fou

nd in

som

e ho

useh

old

clea

ning

pro

duct

s



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Table 2.7. Compatibility of adhesives with different types of tiles [13].

Cementitious OrganicAdhesive Adhesive/ Epoxy-Based

Tiles (with Liquid Latex) Mastic Adhesive

Ceramic S S SHomogeneous S S SGranite U S SMarble U S S

S = Suitable; U = Unsuitable.

Table 2.5. Properties of different tile beddings.

Shear/ Thermal ShearWet Water Compression Tensile Shock Strength

Tile Density Absorption Strength Bond Resistancea 28 DaysBedding (kg/m3) (%) (MPa) (MPa) (MPa) (MPa)

Cementitious ±1300–1650 4% max 7.3–20.7 1.0–3.4 NA 1.6–2.3adhesive

Organic ±1700 4% max 10.0–27.6 1.5–4.1 NA NAadhesive

Epoxy-based ±1300–1700 NA 24.0–55.2 12.4–13.8 >8.3 5.0–8.6adhesive

a High temperatures remove the water in Portland cement mortars very rapidly and prevent the Portland

cement from hydrating, curing completely and gaining full strength. In addition, the rapid drying often

causes mortar to crack, crumble or lose bond to the substrate, tile or stone.

Table 2.6. Compatibility of materials with various types of base [13].

Cementitious OrganicAdhesive Adhesive/ Epoxy-Based

Background Material (with Liquid Latex) Mastic Adhesive

Concrete S S SMasonry S U SCementitious backer board/plaster S S SExisting ceramic, stone, terrazzo S C S

S = Suitable; U = Unsuitable; C = Consult supplier.



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Wet Area 33

2.2.6. Paint

Paints serve as decorative and protective coatings over ceilings andportions of the un-tiled walls in wet areas. A typical paint system is com-posed of primer, sealer, undercoat and topcoat (Table 2.9). Appropriateselection of paint is important as the paint film is subjected to constantmoist conditions in wet areas. Common defects include peeling, flaking,blistering, biological attack and efflorescence.

For long-term performance, the selection should hence consider:

(1) type of substrate,(2) type of environment,(3) application method,(4) surface preparation,(5) overcoating interval.

2.2.7. Service Pipe

Cast iron and plastic pipes have traditionally been used in internal wetareas of high-rise buildings. Due to the poor performance of cast ironunder high humidity conditions, with corrosion and subsequent waterleakage as common maintenance problems [12, 13], they are not used innew constructions of wet areas. Plastic materials are therefore recom-mended for long-term performance of the plumbing system. Chlorinatedpolyvinyl-chloride (cPVC) and polyvinyl chloride (PVC) are the main

Table 2.8. Minimum standards of grout [11].

Properties Test Method Passing Criteria

Linear shrinkage ANSI A 118.6: 1992 ≤ 0.2% at 7 daysWater absorption ANSI A 118.6: 1992 ≤ 10% immersion to dryCompressive strength ANSI A 118.6: 1992 ≥ 15N/mm2 at 28 daysTensile strength ANSI A 118.6: 1992 ≥ 2.4N/mm2 at 28 daysFlexural strength ANSI A 118.6: 1992 ≥ 5.0N/mm2 at 10 days (3 days before

demoulding + 7 days air cure)Color fastness SS 483: 2000 No color change after 28 days or

UV exposure



categories of plastics pipes used in wet areas (Fig. 2.5) [14, 15]. Majorreasons for the growth in use for plastic pipes are longer durability andcost saving in installation, labor and equipment due its lightweight.

2.3. Common Defects in Wet Areas

Common defects often found in wet areas, their possible cause and therole of the parties involved are shown in Fig. 2.6 and Table 2.10.

2.3.1. Waterproofing

2.3.1.1. Design Aspects

Water-tightness of wet areas relies mainly on the adequacy of water-proofing over penetrations, projections and joints and how thesediscontinuities of the floor and wall elements can achieve a “monolithic”

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Table 2.9. Components of paint system.

Component Functions Comments

Primer • To reduce porosity of receiving The primers should be used tosurface so as to prevent undue reduce the porosity of the surfaceabsorption of resin from and have adequate moisturesubsequent coats of paints resistant capability

Sealer • To resist alkali attack from Sealers should be used to reduce thecement-based material porosity of the surface and have

• To stabilize loose surface adequate moisture resistantparticles capability

• To reduce porosity of receivingsurface so as to prevent undueabsorption of resin fromsubsequent coats of paints

Undercoat • To level out minor irregularities Choice of undercoat should beand provide uniform texture compatible with the primer/sealer

• To improve inter-coating and the finishing coatsadhesion

Topcoat • To provide the required The finishing coat of a paint systemfunctions of paint



structure. Water-tightness at interfaces between different componentscould be enhanced by the following design features [16–18]:

(1) Floor wall joints — Use of fiberglass mesh and an angle fillet couldhelp to reinforce waterproofing membrane at joints and to accom-modate any stresses attributed to the structural movement at theabutment of wall and floor (Fig. 2.7). A bond breaker or a flexiblesealant can also be used (Figs. 2.8a and 2.8b).

(2) Pipe penetrations and floor traps — The waterproofing membraneshould be dressed up at pipe penetrations and down into the flooroutlets. Provision of upstands of the membrane together with fiber-glass mesh would maintain the imperviousness at these locations.The details are shown in the Figs. 2.9a and 2.9b.

(3) Shower/bath area — Walls adjacent to the shower and bath areashould be covered with two coats of waterproofing membrane ofmore than 1500 mm in width and 1800 mm in height. For bathtubsthat are designed only for bathing, an upstand of more than 1500 mmof membrane at adjacent wall should be provided.

2.3.1.2 Construction Aspects

Substrate preparation

The substrate receiving the waterproofing membrane should be flat, even,dry and free from debris.

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Wet Area 35

Plastic Pipes

Cross linked polyethylene

(PE-X)

Polybutylene (PB)

Chlorinated polyvinyl chloride

(PVC-C)

Unplasticizedpolyvinyl

chloride (uPV-C)

Acrylonitrile-butadiene-

styrene (ABS)

Co-polymerpolypropylene

(PP)

Fig. 2.5. Classifications of plastic pipes.



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Structural member

Seepage throughstructural joint

Leakage through porous concrete

Efflorescence and leakagethrough cracks

Corrosion and spallingof concrete

Internal finishes (wall, floor and ceiling)

Crack in tiles Tile efflorescence Grout staining Tile debonding

Failure of pointing Dull patch on stone Paint peeling and flaking Blistering

Rust staining Bio-growth: Algae Bio-growth: Fungi Patch on false ceiling

Fixture and fittings

Leakage at pipepenetration

Leakage through floor trap

Corrosion of pipe Water ponding underbathtub

Staining of fittings

Fig. 2.6. Common defects in wet area.



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Wet Area 37

Tabl

e 2.

10.

Com

mon

def

ects

in w

et a

rea.

Def

ects

and

Cau

se g

r.

Cod

ing

Pos

sibl

e C

ause

s of

Def

ects

D*

C*

M*

E*

Stru

ctur

al e

lem

ents

Seep

age

thro

ugh

Prem

atur

e fa

ilure

of

the

poor

qua

lity

or in

com

patib

le m

embr

ane

or in

suff

icie

nt▲

▲

stru

ctur

al jo

ints

(C

1)w

ater

-tig

htne

ss d

ue to

poo

r ap

plic

atio

nD

eter

iora

tion

of th

e w

ater

proo

fing

mem

bran

e w

ith ti

me.

Nee

d re

plac

emen

t▲

gene

rally

aft

er 1

0–15

yea

rsIn

effe

ctiv

e ac

com

mod

atio

n fo

r m

ovem

ent b

etw

een

two

elem

ents

(sl

ab a

nd▲

wal

l) c

an d

amag

e th

e m

embr

ane.

Fib

regl

ass

mes

h at

join

ts is

rec

omm

ende

dD

ry z

one

(usu

ally

with

out w

ater

proo

fing

) is

not

seg

rega

ted

from

wet

zon

e or

▲

wat

er p

ondi

ngM

ain

wat

er s

ourc

e re

mai

ns u

ndet

ecte

d an

d un

atte

nded

▲

Lea

kage

thro

ugh

wal

lPo

or d

esig

n of

wat

erpr

oofi

ng a

djac

ent t

o fi

xtur

es to

pre

vent

see

page

thro

ugh

wal

l▲

or f

loor

(C

2)an

d sl

ab. M

ore

the

num

ber

of w

et w

alls

, hig

her

is th

e ch

ance

of

such

def

ect

No

segr

egat

ion

of d

ry a

nd w

et z

one

▲

Agi

ng o

f w

ater

proo

fing

. Als

o in

flue

nced

by

type

, qua

lity,

dur

abili

ty, f

easi

bilit

y▲

▲▲

of a

pplic

atio

n an

d le

vel o

f us

age

Poro

us c

oncr

ete

(im

prop

er m

ix d

esig

n or

inad

equa

te m

ixin

g) m

ay r

etai

n w

ater

▲▲

and

rem

ain

dam

p fo

r lo

ng. T

oget

her

with

fau

lty w

ater

proo

fing

, wat

er c

anle

ak th

roug

h th

e su

rfac

eTy

pe a

nd m

ount

ing

of f

ixtu

re a

dds

to w

ater

see

page

▲

Dry

zon

e is

not

seg

rega

ted

from

wet

zon

e an

d w

ater

pon

ding

▲

(Con

tinu

ed)



FA


Tabl

e 2.

10.

(Con

tinu

ed)

Def

ects

and

Cau

se g

r.

Cod

ing

Pos

sibl

e C

ause

s of

Def

ects

D*

C*

M*

E*

Eff

lore

scen

ce a

nd

Lea

chin

g of

sol

uble

sal

t or

unhy

drat

ed li

me

from

cem

ent —

Are

sult

of p

oor

▲

leak

age

thro

ugh

qual

ity c

ontr

ol f

or c

emen

t and

impr

oper

cur

ing

crac

ks (

C3)

Wat

er s

eepa

ge d

ue to

cra

cks

resu

lting

fro

m e

xces

sive

shr

inka

ge o

f th

e co

ncre

te▲

▲

(ver

y lo

w w

ater

cem

ent r

atio

or

inad

equa

te c

urin

g)

Cor

rosi

on a

nd s

palli

ngPe

rmea

bilit

y of

con

cret

e is

hig

h du

e to

ver

y lo

w w

ater

cem

ent r

atio

, no

use

of▲

▲

of c

oncr

ete

(C4)

adm

ixtu

re, p

oor

com

pact

ion

Poor

spe

cifi

catio

n of

reb

ars,

e.g

. epo

xy c

oatin

g, s

teel

bar

s, u

se o

f co

rros

ion

▲

inhi

bito

rs, e

tc.

Use

of

bars

alr

eady

with

rus

t and

sca

led

▲

Seep

age

thro

ugh

floo

r tr

ap a

nd o

ther

pen

etra

tions

kee

ps c

oncr

ete

wet

▲▲

▲▲

Age

ing

of m

embr

ane.

Als

o in

flue

nced

by

its ty

pe, q

ualit

y an

d fe

asib

ility

of

▲▲

▲

appl

icat

ion

Vol

ume

incr

ease

of

corr

osio

n pr

oduc

ts c

ause

s sp

allin

g. S

uch

stag

e ca

n re

ach

if

▲

the

initi

al s

igns

of

rust

ing

are

negl

ecte

d

Fin

ishe

sT

ile c

rack

s (C

5)L

ack

of p

rope

r de

sign

ing

or in

stal

latio

n of

mov

emen

t joi

nts

to a

ccom

mod

ate

▲▲

diff

eren

tial m

ovem

ents

of

the

stru

ctur

eE

xces

sive

shr

inka

ge c

rack

s du

e to

lack

of

curi

ng o

f co

ncre

te b

acki

ng▲

(Con

tinu

ed)



FA

Wet Area 39

Tabl

e 2.

10.

(Con

tinu

ed)

Def

ects

and

Cau

se g

r.

Cod

ing

Pos

sibl

e C

ause

s of

Def

ects

D*

C*

M*

E*

Tile

s ar

e po

rous

and

if n

ot s

oake

d pr

oper

ly d

raw

s up

wat

er f

rom

sub

stra

te a

nd▲

▲

caus

e cr

acks

in m

orta

rT

iles

not t

appe

d in

pla

ce, i

.e. h

ollo

w b

acki

ng o

r da

mag

ed b

y ot

her

cons

truc

tion

▲

activ

ities

Eff

lore

scen

ce o

n til

esT

he p

rese

nce

of lo

osel

y bo

nded

san

d, p

re-h

ydra

ted

cem

ent a

nd u

n-hy

drat

ed▲

▲

(C6)

cem

ent m

ix d

ue to

poo

r m

ixin

g du

ring

the

cons

truc

tion

may

leac

h ou

t sol

uble

salts

. Dep

ends

on

mat

eria

l of

scre

ed a

lso

Cra

cks

in ti

le (

C5)

or

grou

t (C

9) a

llow

s w

ater

to s

eep

in. I

t may

lead

to le

achi

ng▲

▲

of s

olub

le s

alts

in c

oncr

ete

back

ing

Stai

ning

or

dull

patc

hT

iles

are

not s

tain

res

ista

nt o

r se

lect

ed a

s pe

r co

lor

cons

iste

ncy

▲▲

on ti

les

(C7)

Gro

ut m

ater

ial i

s no

t dur

able

. With

con

tact

of

wat

er, j

oint

s er

ode

and

blac

k▲

stai

ns m

ay f

orm

Inad

equa

te c

lean

ing

espe

cial

ly f

or in

acce

ssib

le p

arts

or

clea

ning

with

har

mfu

l▲

▲

mat

eria

l or

met

hods

. Cle

anab

ility

is p

oor

Car

eles

s us

e of

wet

are

a, v

anda

lism

▲

Tile

deb

ondi

ng o

r In

adeq

uate

pro

visi

on o

r w

rong

det

ailin

g of

exp

ansi

on jo

ints

▲▲

adhe

sive

fai

lure

(C

8)Po

or b

ondi

ng b

etw

een

inco

mpa

tible

tile

and

bed

ding

▲

Exc

essi

ve d

ryin

g sh

rink

age

of th

e su

bstr

ate

due

to w

rong

mix

des

ign

or

▲▲

insu

ffic

ient

cur

ing

(Con

tinu

ed)



Tabl

e 2.

10.

(Con

tinu

ed)

Def

ects

and

Cau

se g

r.

Cod

ing

Pos

sibl

e C

ause

s of

Def

ects

D*

C*

M*

E*

Abs

orpt

ion

of w

ater

by

inad

equa

tely

soa

ked

poro

us ti

le m

ay le

ad to

a w

eake

ning

▲

of b

ond

Con

tam

inat

ion

of th

e co

ntac

t sur

face

bet

wee

n til

es a

nd s

ubst

rate

by

dust

and

dir

t.▲

It p

reve

nts

prop

er a

dhes

ion

betw

een

the

surf

aces

Inco

rrec

t tili

ng, e

.g. i

nsuf

fici

ent t

appi

ng o

f til

es in

to p

ositi

on o

r lo

ss o

f st

icki

ness

▲

of a

dhes

ive

due

to d

elay

Poor

bon

ding

by

inad

equa

te m

echa

nica

l key

s at

the

tile

back

▲▲

Failu

re o

f po

intin

g (C

9)Po

or q

ualit

y of

gro

ut —

Inf

erio

r st

anda

rd o

r im

prop

erly

mix

ed▲

▲

Dir

t on

the

tile

edge

may

cau

se p

oor

bond

ing

▲

Inco

nsis

tenc

y in

siz

e, th

ickn

ess

or a

lignm

ent

▲

The

tile

d su

rfac

e is

not

pro

perl

y cl

eane

d af

ter

tile

inst

alla

tion

▲

Pain

t pee

ling

and

Poor

pre

para

tion

of th

e su

bstr

ate

may

cau

se p

eelin

g du

e to

impr

oper

bon

ding

▲

flak

ing

(C10

)be

twee

n th

e pa

int f

ilm a

nd s

ubst

rate

Use

of

a pa

int o

f po

or g

rade

or

one

with

exp

ired

she

lf li

fe▲

▲

Blis

teri

ng (

C11

)Pa

intin

g do

ne o

n a

surf

ace

whi

ch is

war

m o

r th

e m

oist

ure

cont

ent i

s >

6%

▲

Its

resu

lt of

inad

equa

te c

urin

gSu

bstr

ate

rem

ains

wet

due

to s

eepa

ge f

rom

upp

er f

loor

at p

ipe

pene

trat

ion

(C15

),▲

▲▲

▲

floo

r tr

ap (

C16

), jo

ints

(C

1) o

r fl

oor

(C2)

The

pai

nt is

not

bre

atha

ble

type

▲

(Con

tinu

ed)

FA




FA

Wet Area 41

Tabl

e 2.

10.

(Con

tinu

ed)

Def

ects

and

Cau

se g

r.

Cod

ing

Pos

sibl

e C

ause

s of

Def

ects

D*

C*

M*

E*

Rus

t sta

in (

C12

)M

igra

tion

and

leac

hing

of

corr

osio

n pr

oduc

ts to

the

surf

ace.

May

be

by

▲▲

▲▲

corr

osio

n of

con

cret

e re

bars

(C

4), p

ipin

g (C

17)

or f

ittin

gs (

C19

)Pa

intin

g on

sub

stra

te a

lrea

dy h

avin

g ru

st s

tain

s. I

n su

ch c

ases

a p

rim

er c

oat

▲

shou

ld b

e ap

plie

d

Bio

logi

cal/o

ther

sta

inM

ain

sour

ce o

f w

ater

rem

ains

una

ttend

ed a

nd u

ntre

ated

. Pro

long

ed d

ampn

ess

▲▲

on f

loor

/wal

ls (

C13

)he

lps

in a

bund

ant g

row

th o

f al

gae

and

fung

i. T

his

is p

reva

lent

in in

acce

ssib

lear

eas

behi

nd o

r be

twee

n fi

xtur

es o

r w

ith f

requ

ent s

plas

hing

of

wat

er f

rom

basi

n or

bat

h. P

robl

em in

crea

ses

with

mor

e nu

mbe

r of

wet

wal

lsPo

or v

entil

atio

n m

aint

ains

a d

amp

hum

id c

ondi

tion

▲

Pain

t is

not f

ungi

or

alga

e re

sist

ant o

r ab

sorb

s w

ater

(no

nwas

habl

e)▲

Uns

uita

ble

or ir

regu

lar

clea

ning

, car

eles

s us

age,

van

dalis

m▲

▲

Firs

t sig

n of

alg

ae/f

ungi

rem

ain

unat

tend

ed a

nd n

ot s

crub

bed

off.

Man

y tim

es▲

▲

poor

acc

essi

bilit

y is

the

reas

on

Bio

logi

cal s

tain

on

Wat

er le

akag

e of

pip

es/H

VA

C d

ucts

abo

ve th

e ce

iling

. Cor

rosi

on r

esis

tant

pla

stic

▲▲

ceili

ng (

C14

)pi

pes

or p

rope

r jo

inin

g re

quir

edE

xces

sive

con

dens

atio

n on

HV

AC

duc

ts▲

The

pla

ster

boa

rd m

ater

ial r

etai

ns m

oist

ure

that

attr

acts

the

grow

th o

f▲

mic

ro-o

rgan

ism

s (e

sp. p

oorl

y ve

ntila

ted

area

s)N

o pe

riod

ic c

heck

ing

of p

ipes

and

HV

AC

duc

ts▲

(Con

tinu

ed)



FA


Tabl

e 2.

10.

(Con

tinu

ed)

Def

ects

and

Cau

se g

r.

Cod

ing

Pos

sibl

e C

ause

s of

Def

ects

D*

C*

M*

E*

Sani

tary

plu

mbi

ngL

eaka

ge a

t pip

ePo

rous

infi

ll of

the

cold

join

t at p

ipe

pene

trat

ion.

Unp

lann

ed p

ipin

g is

▲▲

pene

trat

ion

and

acco

mm

odat

ed b

y ga

p le

ft in

sla

b or

hac

king

join

ts (

C15

)N

o/de

fect

ive

wat

er p

roof

ing

mem

bran

e ar

ound

the

pipe

▲▲

Mem

bran

e is

dam

aged

dur

ing

care

less

inst

alla

tion

of f

ixtu

re/f

inis

hes

▲

Join

ts a

re f

itted

bad

ly o

r po

or a

cces

sibi

lity

for

fitti

ng o

r re

pair

▲▲

Mai

n w

ater

sou

rce

rem

ains

und

etec

ted

and

unat

tend

ed▲

Lea

kage

thro

ugh

floo

rIm

prop

er la

ying

of

floo

r tr

ap▲

trap

(C

16)

Shor

t dis

char

ge p

ipe

or g

ully

pip

e du

e to

impr

oper

layi

ng▲

Poro

us in

fill

of th

e co

ld jo

int a

t the

pen

etra

tion

(usu

ally

unp

lann

ed)

▲▲

Poor

det

ailin

g or

app

licat

ion

of m

embr

ane

arou

nd p

ipe

▲▲

Det

erio

ratio

n of

the

mem

bran

e w

ith ti

me

may

res

ult i

n lo

st o

f w

ater

-tig

htne

ss.

▲

Nee

ds r

epla

cem

ent

Cor

rosi

on o

f pi

pes

Wat

er c

arry

ing

acid

ic ir

on s

alts

may

lead

to th

e co

rros

ion

of c

ast i

ron

pipe

s.

▲▲

(C17

)PV

C p

ipe

is r

ecom

men

ded

Rus

t for

min

g at

join

ts if

not

atte

nded

in ti

me

may

lead

to w

ater

leak

due

to

▲▲

volu

met

ric

expa

nsio

n of

the

join

t. A

diff

icul

t acc

ess

hind

ers

regu

lar

mai

nten

ance

(Con

tinu

ed)



Tabl

e 2.

10.

(Con

tinu

ed)

Def

ects

and

Cau

se g

r.

Cod

ing

Pos

sibl

e C

ause

s of

Def

ects

D*

C*

M*

E*

Wat

er p

ondi

ng u

nder

No/

wro

ngly

pla

ced

floo

r tr

ap b

enea

th th

e ba

thtu

b to

han

dle

wat

er le

akag

e fr

om▲

bath

tub

or o

n fl

oor

the

drai

nage

pip

e(C

18)

If th

e ba

th is

not

enc

lose

d, th

ere

is h

igh

amou

nt o

f sp

lash

on

floo

r▲

Poor

gra

ding

of

floo

r▲

▲

The

join

t bet

wee

n tu

b an

d w

all i

f no

t wat

ertig

ht, a

llow

s se

epag

e th

roug

h to

the

▲▲

unde

rnea

th o

f th

e tu

b. C

usto

m m

ade

tubs

may

leak

Stai

ning

of

fixt

ures

and

Pres

ence

of

high

con

tent

of

sulf

ide

and

chlo

ride

ions

in th

e en

viro

nmen

t (us

ually

▲▲

fitti

ngs

(C19

)in

dust

rial

are

a) m

ay c

ause

pitt

ing.

Sel

ectio

n of

cor

rosi

on r

esis

tant

mat

eria

l(e

.g. P

VC

) re

com

men

ded

Hig

h ch

lori

de c

onte

nt in

wat

er c

an d

estr

oy th

e pa

ssiv

e fi

lm to

for

m c

orro

sion

▲▲

prod

ucts

. Sui

tabl

e m

ater

ial s

houl

d be

sel

ecte

dIn

adeq

uate

cle

anin

g es

peci

ally

for

inac

cess

ible

par

ts o

r cl

eani

ng w

ith h

arm

ful

▲▲

mat

eria

l or

met

hods

Infe

rior

mat

eria

l qua

lity,

poo

r cl

eana

bilit

y or

not

cle

aned

reg

ular

ly▲

▲

Car

eles

s us

e of

wet

are

a, v

anda

lism

▲

D*

— D

esig

n; C

* —

Con

stru

ctio

n; M

* —

Mai

nten

ance

; E*

— E

nvir

onm

ent.

FA

Wet Area 43



FA


Fig. 2.7. Waterproofing at joints.

Fig. 2.8. (a) Use of flexible sealant at floor and wall joint. (b) Use of bond breaker at floorand wall joint.

(a)

(b)



FA

Wet Area 45

(1) Removing imperfections — When the surface has imperfections, itshould be repaired or removed down to sound concrete and patchedup with suitable mortar such as shrinkage compensated grout, poly-mer modified mortar, epoxy mortar, etc. (Fig. 2.10) [19]. Table 2.11shows the common types of surface defects and their repairs.

(2) Cleaning of substrate — Cleaning of the substrate is essential toremove loose and foreign materials from the surface before the appli-cation of waterproofing membrane to ensure excellent bondingbetween the substrate and membrane. Some cleaning methodsinclude high-pressure water jet, cleaning with vacuum cleaner andwith brooms (Figs. 2.11a–2.11c). Both chemical and mechanicalcleaning is recommended for surfaces which contain greasy or oilycontaminants.

Fig. 2.9. Waterproofing detail at (a) pipe penetrations and (b) floor traps.

(a)

(b)



FA


Fig. 2.10. (a) Removing a defective concrete. (b) Patching with mortar.

(a) (b)

(3) Removing surface dampness — Excess water should be removedfrom the surface prior to waterproofing application. Surface can bedried by natural ventilation or with the use of mechanical blowers toaccelerate the drying process (Fig. 2.12).

Membrane application

Considerations should include:

(1) Size of the team — In internal wet areas, the area to be waterproofedis relatively small thus the size of the team should not be too largegiven the space constraints.

(2) Size of the mixes — Mixing of waterproofing products should bedone in a controlled environment according to the manufacturer’sspecifications. All waterproofing products should be mixed mechan-ically to ensure even mixing. The proportion of a two-part system ifnot pre-packed, should be measured out as accurately as possible andmixed within the specified time.

(3) Tools — Tools and equipment used for application should be cleanedbefore and immediately after application. Table 2.12 shows thedifferent tools used for different types of systems.

The application of membrane should begin at a corner: diagonal to theentrance and upturns at wall floor junctions, to avoid stepping on appliedarea. Rollers or brushes can be used for application of membrane in most



FA

Wet Area 47

Tabl

e 2.

11.

Com

mon

sur

face

impe

rfec

tions

and

rep

air

met

hods

[16

].

Def

ect

Met

hod

Tool

Cra

cks

Hac

k ou

t a V

-gro

ove

to a

min

imum

dep

th o

f 25

mm

.H

ack

out a

V-g

roov

e us

ing

a ha

mm

er a

nd c

hise

l or

aR

emov

e al

l loo

se d

ebri

s fr

om a

ffec

ted

area

.m

echa

nica

l hac

ker.

Mix

pat

chin

g co

mpo

unds

usi

ngPl

aste

r ba

ck to

ori

gina

l pro

file

usi

ng n

onsh

rink

drill

s an

d m

ixin

g at

tach

men

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Fig. 2.11. Cleaning of substrate: (a) cleaning with a broom, (b) cleaning with a vacuumcleaner and (c) cleaning with high pressure water jet.

(a) (b) (c)

Table 2.12. Different tools used for application of different membranes.

Type of System Tools for Application

Polyurethane-based Usually by brush, squeegee or broom.Vertical grade by brush or trowel

Rubber-based Brush, rollers or airless spray

Acrylic-based Usually applied by rollers to work material into fiberglassreinforcement

Cementitious-based Usually by brush or spray followed by troweling

Fig. 2.12. Mechanical blowers to dry the surface faster.



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Wet Area 49

locations. Rollers having the same width as the upturn could achieve aneven and uniform application [20]. However, critical locations where pipepenetrations and wall joints exist should be waterproofed using a brush toensure good coverage. Figure 2.13 illustrates the application procedurefor wall and floor.

Curing

It is vital to allow the waterproofing membrane to cure properly beforeperforming any tests so as to prevent any premature failure of the water-proofing system. Table 2.13 highlights the common curing method fordifferent systems.

Protection

Protecting the waterproofing membrane is the last step in the water-proofing process. The waterproofing contractor should ensure thatworks are carried out under controlled conditions and protection shouldbe provided to the membrane immediately after application. The areawaterproofed should be cordoned off.

Quality assurance

To uphold the final performance of membrane, it is important to carry outintermittent inspections during the application. Table 2.14 illustratesbasic checks that can be performed before and after the application ofwaterproofing membrane.

2.3.2. Screed


Design of screeds requires careful considerations of fitting layout in wetareas to provide required falls and accommodate services for plumbing.These include:

(1) Gradient of falls specified should be adequate to allow for efficientdrainage of runoff. The directions of slopes should be clearly



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Fig. 2.13. (a) Waterproofing application on wall. (b) Waterproofing application process offloor.

Waterproofing to min 1500 mm height forbathtub area

Waterproofing at shower area to min 1800 mmheight and min 1500 mm width

Application begins at a corner Apply upturn at the wall and floor joints

Application of fiber glass mesh at joints Application at floor trap

Sufficient upturn at pipe penetrations Complete application

(a)

(b)



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Wet Area 51

Table 2.13. Curing methods and curing time.

Type of System Curing

Polyurethane-based Moisture curedRecommended 24 h curing timeContains solvent thus requires ventilationTo be cured at least 72 h before flood test

Polyisoprene/ Air-dryingrubber-based About 1 h in exposed condition, 3–4 h in enclosed areas

Recommended 72 h before flood test

Acrylic-based Air dryingWithin 1 h, but requires minimum four to five coats due

to reinforcementTotal system therefore requires longer drying time

Cementitious-based Moisture curedNormally 1–2 hFlood test within 24 h to assist in curing

Table 2.14. Inspection during the application of waterproofing membrane.

Stage of Work Check Criteria for Rejection

Checking for surface preparation Dust If excessive white powder on thecloth when wiping with adark cloth

Oil If standing droplets appears whilesprinkling the water

Laitance If excessive lose powdered materialsare observed when the surface isscraped with a knife

Checking for application Water leakage Waterponding test:Temporarily seal all outlets and

flood the whole area to aminimum depth of 25 mm

Ensure that the water level is notabove the finished level of themembrane upturn at wall at theend of the test

Flooding time is 24 h. Inspect deckbelow for leakage



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indicated in the drawings (Fig. 2.14). The minimum gradient of thefall at shower areas or wash areas should be maintained at 1:60towards the floor trap.

(2) The thickness of screed may be determined by the size of the servicesthat are installed within screed, as the overall depth of the screed isto be increased by the depth of the particular service accommodated.

2.3.2.2. Construction Aspects


The surface of the substrate should be roughened to form mechanical keyto enhance good adhesion of screed. For reinforced concrete wall, the sub-strate to receive render should be spatter-dashed with cement/sand (ratio1:2 by volume) or latex adhesive. The protrusion thickness of spatter-dashshould be about 3–5 mm [8].

Screed application

Proper application can be achieved through the following:

Planning — Prior to application, the entire wet area surface should beplanned to accommodate required levels and falls accordingto the drawings. Level packs can be used to mark therequired level of the screed layer and to ensure the correctfalls to the floor outlets (Fig. 2.15).

Fig. 2.14. Minimum slope to fall to achieve efficient drainage of water towards thedrainage point.

Minimum slope to fall is1: 60



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Wet Area 53

Mixing — To achieve consistency, pre-packed mortar mix is recom-mended over conventional site mixing of cement sand andmortar. Pre-packed mortar is a dry product of cement, sandand performance-enhancing additive. Proper mixing of correctproportion of water and dry mixture should be carried outusing mechanical mixers prior to screeding (Fig. 2.16).

Placing — Laying of screed should be carried out by spreading10–20 mm surcharge over the base surface. The total accept-able thickness should not be less than 50 mm for unbondedscreed [21, 22]. Thinner (less than 50 mm) layers may beacceptable with high-quality screeds and sound workmanship.Where thickness is greater than 50 mm, it should be laidin two layers and each layer should be well-compactedto remove voids [23, 24]. The following practices can befollowed during the laying of screed:

� A wooden float can be used to roughen the surface toreceive the next coat. The recommended curing time forthe first coat is 24 h.

� Subsequently, the next coat could be applied in the samemanner until the required thickness is achieved (Fig. 2.17).

Level packs

Fig. 2.15. Use of level packs.



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This may be achieved either by setting the timber battensaccurately to the required level or by the use of level packs.

� To ensure consistency in the surface flatness, the width ofthe screed bay should be limited to a maximum of 4–5 m.

Fig. 2.16. Use of a mechanical mixture.

Fig. 2.17. Leveling the surface.



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Wet Area 55

� The layout of the screed bays and joints should beconsistent with the movement joints in the structural baseor with rigid tile joints.

� A plumb or level should be used to check the levelness ofthe surface.

Curing

The screed should be air-cured for at least seven days to achievemaximum strength. Water may be sprayed during the first two days tofacilitate the hydration of cement.

Quality assurance

The following are tolerances for finished surface regularity [24–29]:

• Floor:

� 3 mm for tiles to be fixed with adhesive� 5 mm for tiles to be fixed with cement sand and mortar� 10 mm for tiles to be fixed with cement and sand semi-dry mix

• Wall:

� 3 mm for tiles to be fixed with adhesive� 6 mm for tiles to be fixed with cement sand mortar

2.3.3. Tiling


Good detailing of tiling would enhance prolonged durability and betterperformance of the system. Movement joints, tile sizes, grouting materi-als and pointings are important issues to be considered during the designstage to minimize defects occurrence during construction and postoccupancy stages.

Movement joint

Movement joints extending through the tiling and the substrate shouldbe installed to accommodate stresses due to shrinkage, deflection and



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moisture. The recommended maximum spacing and width of movementjoints [23] are:

• Internal wall: Horizontal and vertical directions: 5–6 m• Wall joint width: Minimum 3 mm, preferred 5 mm• Internal floor: 5–7 m in all directions• Floor joint width: Minimum 5 mm

The spacing and width of joints should be consistent with the movementjoints provided in the substrate (Fig. 2.18). Stress relief joints designedin the tile layer should coincide with joints in screed to ensure consistentdifferential movements throughout the system (Fig. 2.19).

Pointing width

Pointing accommodates movement of tiles due to temperature change,dimensional instability or moisture absorption. Tables 2.15–2.17 show therecommended widths for various types of tiles and grouts.

2.3.3.2. Construction Aspects


The substrate surface should be flat and even to receive the tiles. Dirt and for-eign particles should be removed by cleaning prior to tiling works (Fig. 2.20).

Fig. 2.18. Details of a typical movement joint [23].



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Wet Area 57

Planning

(1) Selection of tile — Inherently, tiles may have some dimensional vari-ations due to the production process. To ensure consistent width oftile joints, the dimension of tiles to be laid in each area should be

Table 2.15. Recommended pointing widths for polymer modified grout.

Joint Width (mm)

Tile Size (mm) 1.5 3 6 9

25 × 25 × 6 4.8 2.6 1.6 1.350 × 50 × 6 8.8 4.8 2.6 1.9106 × 106 × 7.5 14.9 7.7 4.0 2.8100 × 200 × 12 11.7 5.9 3.1 2.1100 × 200 × 30 4.8 2.5 1.3 0.9150 × 150 × 9 17.5 8.9 4.6 3.2150 × 150 × 12 13.1 6.7 3.5 2.4200 × 200 × 9 23.0 11.8 6.0 4.0300 × 300 × 9 34.7 17.5 8.9 6.0325 × 325 × 9 — 18.9 9.6 6.5400 × 400 × 9 — 23 11.8 8600 × 600 × 9 — 34.6 17 11.8

Approximate m2 coverage. Source: www.laticrete.com (Courtesy: Laticrete International Inc).

Fig. 2.19. Typical details of a stress relief joint [23].



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Table 2.16. Recommended joint width for cementitious grout.

Joint Width (mm)

Tile Size (mm) 3 6 9 12

25 × 25 × 6 5.8 — — —50 × 50 × 6 10.4 — — —100 × 100 × 12 9.8 5.2 3.7 2.7150 × 150 × 9 19.2 10.0 7.0 5.5150 × 150 × 9 14.4 7.4 5.2 4.0200 × 200 × 9 25.4 13.0 9.0 7.0300 × 300 × 9 37.7 19.0 13.0 9.8325 × 325 × 9 40.7 20.7 14.0 10.8400 × 400 × 9 50.0 25.4 17.0 13.0600 × 600 × 9 74.3 37.0 25.4 19.2


Fig. 2.20. Surface cleaning.

Table 2.17. Recommended joint width for unsanded grout.

Joint Width (mm)

Tile Size (mm) 1.5 3 6 9

106 × 106 × 7.5 42 26 — —150 × 150 × 7.5 58 30 — —200 × 200 × 9 65 33 — —300 × 300 × 9 96 49 — —




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Wet Area 59

controlled within a 1 mm variance. This can be done by sorting in thefactory and providing a marking of the size range on the tile box foridentification. Sorting of tiles should be carried out on site with theuse of a V-box as shown in Fig. 2.21 or other devices. During thesorting process, tilers should also look out for other blemishes, suchas cracks, warp, chip and nonsquareness.

(2) Cutting and Termination — Tiles laid around doorframes and sanitaryfittings should be cut to maintain consistent tiling work. The cuttingpositions should be planned, marked (Fig. 2.22a) and cut (Fig. 2.22b).A grinder should be used to smoothen the edge of the cut tiles toprevent the cut tiles from being either jagged or sharp (Fig. 2.22c).

(3) Marking — To achieve alignment and consistent joint width, ade-quate reference lines should be marked on the screed to facilitate tileinstallation. A string can be used to imprint a colored dye on screedas the reference line for alignment of tiles (Fig. 2.23).

Installation

Man-made tile

Manmade tiles are usually fixed with modified cement mortar:

• Tiles should be dampened for at least 12 h to saturated-surface-dry(SSD) condition to prevent excessive absorption of water from the

Fig. 2.21. Sorting tiles in a “V” box (Courtesy: Housing Development Board).



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screed (Fig. 2.24a) and they should be stacked vertically to drain offthe water (Fig. 2.24b). At the point of laying, the surface of the tilesshould be dry. Tests should be carried out on glazing tiles to confirmthat soaking would not lead to crazing.

• Mortar should be prepared in accordance with the manufacturer’sinstructions (Figs. 2.25a–2.25d).

• Mortar should be applied to a consistent thickness of not more than10 mm and should not be spread over a coverage that could not becovered with tiles in time as the surface of adhesive may form a skinwhich prevents bonding. The maximum spread should be limited to

Fig. 2.22. Cutting and termination of tiles. (a) Mark the recess. (b) Cutting along theoutline. (c) A grinder is used to smoothen the cut edges.

(b)

(c)

(a)



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Wet Area 61

about 1 m2 (Fig. 2.26a). However, for adhesives, “open time” of theadhesive film should be considered in this regard.

• The mortar bed shall be allowed to stiffen slightly.• The background of the tiles should be cleaned thoroughly (Fig. 2.26b).• Mortar should be spread on the cleaned background of the tile. The

keys and frogs on the tile back should be completely filled up withmortar, with a thickness of not less than 2 mm but not more than 6 mmexceeding the depth of keys or frogs (Fig. 2.27).

• The tiles should be then placed firmly with a twisting motion (do notslide tiles in), ensuring regular and straight joints to a recommended

Fig. 2.23. Imprinting lines for alignment of tiles.

Fig. 2.24. (a) Soaking of tiles. (b) Drying of tiles.

(a) (b)



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width. Once they have been put in position, they should be uniformlytapped using a hammer into place to achieve good contact. A block(Fig. 2.28) should be used to prevent over-hammering causing thetiles to chip or crack.

(a) Adhesive binder (b) Performance additive

(c) Water (d) Prepacked mortar

Fig. 2.25. Mortar preparation.

(a) (b)

Fig. 2.26. (a) Spreading of the adhesive. (b) Cleaning of the tile background.



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Wet Area 63

• Spirit levels should be used to check surface levelness and evennessduring tile installation and after fixing (Fig. 2.29). For bigger sizetiles, a further check of levelness can be carried out about 2–3 h afterlaying. This is to prevent unevenness of tiles caused by tile settlementdue to self-weight.

Keys or frogs to fill up the back of the tile completely

Fig. 2.27. Application of mortar to tiles.

Use a hammer to lightly tap the tiles in place, the blockis used to prevent over-hammering that will chip orcrack the tiles

Fig. 2.28. Fixing of the tile firmly into the bedding.



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• Tile spacers can be used to achieve neat and consistent joint widths(Fig. 2.30). These spacers should be easily removable and not causestaining to the tiles.

Natural stone tile

During installation, preparation of natural stone tiles is very important toprevent defects such as, efflorescence, cracking, debonding and tonality.

Fig. 2.29. Checking surface levelness.

Tile spacers

Fig. 2.30. Tile spacers for consistent spacing between tiles.



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Wet Area 65

(1) Pre-treatment — Pre-treat the edges and the front surface with awater repellent impregnator by spreading it evenly as natural stonetiles have high water affiliation (Fig. 2.31). However, caution shouldbe exercised when attempting to coat the back face of the tiles witha sealer as it may act as a bond breaker preventing the beddingmaterial from adhering properly.

(2) Curing — The treated tile should be allowed to cure properly beforelaying.

(3) Setting natural pattern — The floor tiling should be set out in linewith the natural pattern of the tiles starting from the center of theroom and in straight lines parallel to the axes of the room. However,for irregularly shaped rooms where cutting of tiles are unavoidable,cut tiles should be placed at the least noticeable locations.

(4) Cleaning — The back of the tiles should be wiped with a damp clothor brush to remove dust (Fig. 2.32).

Fixing of tiles should be carried out with suitable adhesive that should bein accordance with manufacturer’s instructions.

• A skim-coat of the bedding mix should be spread on the receivingsurface using the flat side of a notched trowel so as to cover itcompletely. A V-notched adhesive trowel should be used, holding it at

Fig. 2.31. Application of impregnator to natural stones.



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Fig. 2.32. Cleaning the back of the stone.

a 45°–75° angle (Fig. 2.33). Trowel’s angle should be kept consistentand straight to create uniform ridges in the adhesive so as to obtain alevel setting surface.

• A layer of adhesive should be applied over the backside of the tile tocover the surface entirely (Fig. 2.34).

• The tile should be laid onto the bedding with a firm pressure andadjusted within a limited time specified by the bedding material’smanufacturer.

• Once the tiles are put in position, tap uniformly on the tiles to achievegood surface contact.

• A spirit level ensures that the tiles laid are even and level.• Appropriate plastic spacers or spacing rod (for wider joints) should be

used to control the uniformity of the joint widths. Normally, joints forsmooth tiles are at least 1 mm wide while for textured tiles arebetween 6 and 10 mm (Fig. 2.35). Widths should comply with thestandard requirements (Tables 2.15 to 2.17).



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Wet Area 67

• To check for complete adhesion behind large tiles, random removal oftiles could be carried out as work proceeds (Fig. 2.36). In general, adhe-sive must cover 90% of the back of any tile which is randomly removedfor checking. If this condition is satisfied, the adhesive is cautiouslyremoved from the tile and the substrate and re-applied with fresh adhe-sive. If this condition is not satisfied, other tiles in the vicinity of theoriginal tile should be removed to check if the fault is general.

Fig. 2.33. Troweling at 45°.

Fig. 2.34. Application of adhesive to tile.



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Fig. 2.35. Consistent joints.

Fig. 2.36. Removal of tiles to check for adhesion.

Grouting

Grouting of tile joints has a significant impact on the overall appearanceof the finishes. White cement is commonly used due to its low costs.



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Wet Area 69

Polymer modified grouts which are usually formulated with good work-ing characteristic, low shrinkage, good adhesion to the sides of the jointsand higher durability are gaining popularity.

• Prior to grouting, the joints should be brushed clean to remove excessmortar.

• Saturate the tile before grouting to prevent migration of grout pig-ments into the pores of tiles. Joints that are to receive resin-based orpolymer-modified cementitious grouts should be dry.

• The mixing of the material should be done in accordance with themanufacturer’s instructions.

• Spread a grout over the entire surface of the tile. The mortar shouldbe pressed sufficiently with a rubber float so that it flows along thejoint and occupies all voids (Fig. 2.37a). Any excess grout on the tilesurface should be cleaned away immediately with a sponge so as toavoid staining to the tile surface (Fig. 2.37b).

Rubber floats tosmooth over joints

Use sponge to cleanthe tile surface

Fig. 2.37. (a) Grouting. (b) Removing excess grout.

(a) (b)



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Cleaning and protection

All loose material and residual cement should be brushed off and thesurface washed with clean water to remove dirt. Protection to the tilingworks should be provided immediately after its completion. This canbe done by covering the tiled area with polyethylene sheets, cardboardsor wooden boards (for heavy traffic) until the entire system has cured(Fig. 2.38). The protective material should be sufficiently thick to with-stand human traffic, abrasion and impact, impermeable to water andwould not stain under wet and dry conditions.

Quality assurance

Table 2.18 illustrates a check list to assure the standard of the finishes inwet areas.

2.3.4. Ventilation and Air Circulation

In addition to removing odor, adequate air circulation is vital to extractdampness which is responsible for defects such as biological growth onfloors, ceilings and walls. Proper air circulation can be achieved bynatural or mechanical ventilation or a combination of both. Exhaust fans

Fig. 2.38. Protection to completed tile works.



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Wet Area 71

Tabl

e 2.

18.

Ach

eck

list f

or f

inis

hes

in w

et a

reas

.

Che

cks

Wal

l Tili

ngF

loor

Tili

ng

1.To

lera

nces

for

sur

face

une

venn

ess

2. I

nter

face

with

oth

er e

lem

ents

(Con

tinu

ed)

�Su

rfac

e un

even

ness

ove

r 1

m le

ngth

≤1.

5m

m�

Une

venn

ess

betw

een

two

tiles

ove

r th

e jo

int ≤

1m

m

�T

ile in

terf

ace

with

cei

ling,

win

dow

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mes

,do

or f

ram

es, p

ipes

, etc

. are

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ned

and

cons

iste

nt



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Tabl

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18.

(Con

tinu

ed)

Che

cks

Wal

l Tili

ngF

loor

Tili

ng

3. J

oint

s, to

nal v

aria

tions

4. H

ollo

wne

ss, c

hip

offs

, sha

rp e

dges

and

cra

ck

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ints

are

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ned

and

with

con

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ent s

ize

betw

een

1 an

d 2

mm

�Jo

ints

are

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nea

tly w

ith n

o vo

ids

with

in th

em�

The

join

t wid

th s

hall

be le

ss th

an 5

mm

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ints

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r un

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ace

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ree

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nd h

ollo

w ti

les



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Wet Area 73

and ventilation ducts should be located within 3 m of the fan inlet orintake grill [30]. According to SS CP 13:1999 [31], the minimum requiredoutdoor air supply is 10 air exchange per hour (ACH). For areas wherethey are entirely mechanically ventilated, minimum air exchange rateshould be 15 ACH.

Intake grills should be provided at low levels near to W.C.s and uri-nals. This would enable foul-air to be extracted quickly (Fig. 2.39). Theexhaust air should be discharged at least 2 m away from the pavementlevel and at least 5 m away from any window.

2.3.4.1. Plumbing

Layout

An efficient plumbing layout reduces the need for penetrations throughwaterproofing membrane. Important considerations include:

(1) Detailed drawings of the layout of service pipes that are to be castwith the floor slab should be provided. These detailed layouts shouldinclude details such as gradients of horizontal pipes, joints andconnections (Fig. 2.40) [32].

Fig. 2.39. Exhaust intake grill of mechanical ventilation.



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(2) The number of wet walls (Table 2.19a) and pipe penetrations(Table 2.19b) through wall and floor should be minimized. Singlewet wall design with a common discharge stack can reduce thenumber of penetrations (Fig. 2.41).

(3) Raised floors provided around the pipe could minimize contactbetween water and pipes (Fig. 2.42) and reduce the chances of waterleakages through pipe penetrations or corrosion of the pipe (cast iron).

Accessibility

The accessibility for repair and replacement of service pipes is one of themajor concerns that should be addressed during the design stage.Openable covers and walk-in pipe ducts can be provided to facilitateaccess for maintenance (Figs. 2.43–2.45). In addition, designers shouldtake into consideration the positions of service pipes with regards to theaccessibility of the entire floor or wall area for cleaning. The pipes shouldnot inhibit the ease of cleaning of floor and wall surfaces.

2.3.4.2. Sanitary Fittings

Sanitary fittings should be installed such that to provide convenience tothe user and to facilitate maintenance work.

Fig. 2.40. A typical detail of plumbing system [28].



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Wet Area 75

(1) Shower/bath or wash area — Separation of shower/bath or washareas from the common toilet areas is a good practice to minimizewater from affecting the entire floor area. Enclosed areas or keepinglevel differences not less than 75 mm between shower/wash areasand the other areas or use of “kerbs” can control the water flow(Figs. 2.46a and 2.46b).

(2) Lavatory — Washbasins can be installed into the preformedcountertop or vanity top with a splashback of minimum height of100 mm and an apron edge to prevent overflowing of water from the

Table 2.19(a). Complexity of plumbing details for different numbers of wet walls.

Criteria

When the number of wet walls is 1 (minimum), the plumbing details are simple

• The discontinuities may be minimum, reducing the risk of water leakages• Maintenance of the system may be easy due to the simple layout

When the number of wet walls is 2 (moderate), the plumbing details are relatively simple

• The discontinuities may be relatively small, reducing the risk of water leakages• Maintenance of the system may be relatively easy due to the simple layout

When the numbers of wet walls is >>2 (large), the plumbing details are more

• The discontinuities may be relatively high, increasing the risk of water leakages• Maintenance of the system may be relatively difficult due to the complex layout

Table 2.19(b). Recommended number of penetrations for different sanitary fittings.

Fittings Recommended Number of Penetrations

Urinal/WC 1 trap shall be provided to serve a maximum of 10 urinals.For more than 10 urinals, more than one trap shall be provided

Washbasin 1 wash basin trap shall be provided to serve a maximum of10 wash basins. For more than 10 wash basins, more thanone trap shall be provided

Wash/shower/bath 1 floor trap for every 3 WC cubicles provided that the separatingwall/partition does not touch the floor level and the other2 WC cubicles are graded to fall towards the floor trap inthe third WC cubicle

Source: Ministry of Environment.



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basin [33] (Fig. 2.47). If the wash basin is not fixed to a vanity top (i.e.free standing or wall hung type), a minimum size of 550 mm in lengthand 400 mm in width should be provided to prevent water from splash-ing onto the floor (Fig. 2.48). In addition, it can be fixed away from thewall to minimize water seepage through adjacent wall (Fig. 2.49).

(3) Water Closet (WC)/urinals — Wall-hung toilet bowls may beselected to facilitate the ease of cleaning the floor (Fig. 2.50) [13].

Fig. 2.41. Common stack.

Access panel provided at false ceiling for maintenance

Fig. 2.42. Raised levels. Fig. 2.43. Access panel.



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Wet Area 77

Fig. 2.44. Wall mounted pipes.

Fig. 2.45. Walk in pipe ducts.



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Spatial design

The location of fixtures affects greatly the ease of floor cleaning. Thefollowing guidelines may enhance efficient maintenance:

(1) between two wash basins — Minimum distance of 800 mm(Fig. 2.51),

(2) between two WCs — Minimum distance of 750 mm (Fig. 2.52),(3) between two urinals — Minimum distance of 750 mm (Fig. 2.53).

Level difference

kerb

Fig. 2.46. (a) Level differences at a shower. (b) Kerb.

(a) (b)

Flashback

Apron edge

Fig. 2.47. Preformed vanity top with apron edge.



FA

Wet Area 79

550 mm 400

mm

Fig. 2.48. Recommended dimensions of basins.

Fig. 2.49. Free-standing washbasin fixed way from a wall.



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Fig. 2.50. Wall hung toilet bowl.

Ease of cleaning

Fig. 2.51. Minimum distance between washbasins.

Min 800 mm

Min 500 mm



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Wet Area 81

Fixing of sanitary fixtures

Sanitary fixtures — If a sanitary fixture abuts the wall or within 75 mm ofthe wall (e.g. bench top), the waterproofing membrane should be dressedup to a minimum height of 150 mm from the fixture surface (Fig. 2.54).

Fig. 2.52. Minimum distance between WCs.

Min of 750mm Min of 750mm

WC WC WC

Min 450mm Min 450mm

Fig. 2.53. Minimum distance between urinals.



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Figure 2.55 illustrates different applicable details of sealed joints betweensanitary fittings and wall to prevent water seepage. A supporting wall canalso be erected away from the backing wall to fix the fitting. This wouldminimize the chances of water penetration through the wall (Fig. 2.56).On the other hand, additional floor traps should be provided to facilitateefficient drainage to prevent water ponding (Fig. 2.57). For instance,areas underneath the bathtub and shower tray are critical locations wherewaterponding may arise.

2.4. Maintenance

All building elements start to deteriorate from the moment they are com-pleted. Maintenance which includes cleaning, repair and replacement, areessential to regulate the pace of building deterioration.

Fig. 2.54. Sanitary fitting abutting to the wall.



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Wet Area 83

Fig. 2.55. Sealed joint between sanitary fittings and wall.

(a) Sealed joint over sanitary fixture (d) Sealed joint at basin abutting surface

(b) Sealed joint at bath (e) Sealed joint between fixture and bench top

(c) Sealed joint at sanitaryfixture

Impervious surfacenot less than 150 mmabove fixture andextending overflange

Flange(12 mm min)

Flexible sealant(3 mm min)

Sanitary fixture

Impervious surface not less than150 mm above fixture

Flexible sealant (3 mm wide x 5 mmdeep)

Basin (abutting animpervious surface)

Impervious surface not less than 150 mmabove the fixture and extending over flange

Wall notched to takeflange

Flexible sealant(3 mm min)

Bath

Not more than10 mm

Impervious surface not lessthan 150 mm above bench top

Flexible sealant at top and back of bench top

3 mmmin.

Seal joint between fixture and bench top to preventmoisture penetration

Impervious surface not less than 150 mmabove fixture

Flexible sealant (3 mm min)

Sanitary fixture



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Fig. 2.57. An outlet to provide drainage from beneath the bathtub.

Fig. 2.56. Supporting wall.

Backing wall

Waterproofing membrane

Supporting wall

Seal joint

Supporting wall

Cleaning method of wet area varies depending on the type of finishesused. Table 2.20 outlines certain practices for normal cleaning to keep wetareas maintainable.

Special cleanings are necessary for unexpected stains (Table 2.21).These stains can be due to various activities of humans and prolongedexposure of the surfaces for certain solutions.



FA

Wet Area 85

Tabl

e 2.

20.

Cle

anin

g m

etho

ds.

Typ

e of

Fin

ishe

sC

eram

ic/H

omog

eneo

us T

ileG

rani

teM

arbl

eP

aint

Spec

ific

atio

nsU

ngla

zed

cera

mic

tile

s or

qua

rry

Nat

ural

gra

nite

and

oth

er

—Pa

int t

o SS

CP

22til

es to

SS

CP

68: 1

997

orig

neou

s ro

cks

spec

ifie

d an

dB

S 64

31 P

art 1

, 198

3, w

ithse

lect

ed to

BS

5390

: 197

6te

st c

ertif

icat

ion

toIS

O 1

0545

: 199

5G

laze

d ce

ram

ic ti

les

to B

S 64

31Pa

rt 1

, 198

3 or

to S

S C

P68

:199

7,w

ith te

st c

ertif

icat

ion

toIS

O 1

0545

, 199

5

Mai

nten

ance

Reg

ular

mop

ping

and

buf

fing

Reg

ular

mop

ping

and

buf

fing

Reg

ular

mop

ping

and

buf

fing

Cle

anin

g

Met

hod

Aso

lutio

n of

1/4

-cup

low

-sud

sN

atur

al c

lean

er w

ith h

igh-

As

a ru

le o

f th

umb,

cle

anin

gW

ashi

ng w

ithde

terg

ent (

solu

tions

pro

duce

less

foam

ing

jet (

with

out

solu

tions

that

con

tain

any

clea

n w

ater

isbu

bble

s) o

r 1–

2 ta

bles

poon

s of

pres

sure

) is

sui

tabl

e. I

t is

form

of

acid

s, p

hosp

horu

s,su

ffic

ient

on

eith

er w

ashi

ng s

oda

or tr

i-so

dium

reco

mm

ende

d to

avo

idch

lori

ne o

r sc

ouri

ngsu

rfac

es th

atph

osph

ate

or c

omm

erci

al f

loor

acid

ic, h

igh

alka

line

and

pow

ders

sho

uld

not b

e ha

ve m

inor

clea

ning

pow

der

shal

l be

mix

edch

lori

nate

d pr

oduc

tsus

ed o

n po

lishe

d m

arbl

est

ains

and

dir

t

(Con

tinu

ed)



FA


Tabl

e 2.

20.

(Con

tinu

ed)

Typ

e of

Fin

ishe

sC

eram

ic/H

omog

eneo

us T

ileG

rani

teM

arbl

eP

aint

wel

l in

1 ga

llon

wat

er to

cle

anH

owev

er, d

ry c

lean

ing

Thi

s w

ould

mak

e m

arbl

e If

nec

essa

ry,

the

floo

rm

etho

ds a

re r

ecom

men

ded

look

s du

ll or

suf

fer

from

a

mild

det

erge

ntov

er f

requ

ent w

et c

lean

ing

peel

ing

effe

ct k

now

n as

m

ay b

e us

edm

etho

ds in

wet

are

a“o

rang

e pe

el”

unle

ssfo

r he

avy

adhe

ring

to th

e ca

utio

ns

stai

nsan

d/or

for

mul

as p

rovi

ded.

In

add

ition

, any

type

of

abra

sive

pro

duct

sho

uld

also

be

avoi

ded,

in o

rder

to

pre

vent

scr

atch

es a

nd

loss

of

shin

e

For

polis

hed

fini

shin

g sm

all

Plai

n w

ater

can

be

used

to r

emov

ear

eas,

use

of

war

m w

ater

dirt

. How

ever

, for

hea

vier

soi

ling,

wou

ld b

e su

ffic

ient

for

a m

ild d

eter

gent

sol

utio

n is

peri

odic

cle

anin

gre

com

men

ded.

The

sol

utio

n sh

all

(Con

tinu

ed)



FA

Wet Area 87

Tabl

e 2.

20.

(Con

tinu

ed)

Typ

e of

Fin

ishe

sC

eram

ic/H

omog

eneo

us T

ileG

rani

teM

arbl

eP

aint

be w

ell-

mix

ed b

efor

e us

ing.

The

surf

ace

shou

ld th

en b

e ke

pt d

ryfo

r m

ore

shin

e

Cle

anin

gR

esid

enti

al: T

wic

e a

wee

kR

esid

enti

al: T

wic

e a

wee

kR

esid

enti

al:T

wic

e a

wee

kN

o fr

eque

ntfr

eque

ncy

cycl

esC

omm

erci

al a

nd i

nsti

tute

s:

Com

mer

cial

and

ins

titu

tes:

Com

mer

cial

and

ins

titu

tes:

Thr

ee ti

mes

a d

ayT

hree

tim

es a

day

Thr

ee ti

mes

a d

ayO

ffic

es a

nd i

ndus

tria

l: Tw

ice

a da

yO

ffic

es a

nd i

ndus

tria

l: Tw

ice

Off

ices

and

ind

ustr

ial:

Twic

ea

day

a da

y



FA


Tabl

e 2.

21.

Typi

cal e

xam

ples

of

requ

irin

g sp

ecia

l cle

anin

g.

Typ

es o

f So

iling

Exa

mpl

eT

ypic

al S

ourc

esC

lean

ing

Met

hods

Soap

scu

mSo

ap•

Spon

ging

with

a m

ixtu

re o

f 1/

2 cu

p pa

ckag

ed w

ater

sof

tene

r,2

tabl

espo

ons

rotte

nsto

ne a

nd 1

cup

hot

wat

er•

With

a s

olut

ion

of 1

–2 ta

bles

poon

s tr

isod

ium

pho

spha

te in

1ga

llon

hot w

ater

Mild

ewD

ampn

ess

in•

Cle

an w

ith a

dilu

te s

olut

ion

of c

hlor

ine

blea

ch in

wat

erto

ilet

•U

sing

a m

ildew

-ret

arda

nt h

ouse

hold

spr

ay•

The

dir

ectio

ns o

n th

e la

bel o

f th

e so

lutio

ns s

houl

d be

str

ictly

follo

wed

Rou

gh w

hite

Min

eral

bui

lt up

•It

may

be

diss

olve

d w

ith a

com

mer

cial

tile

cle

aner (C

onti

nued

)

coat

ing



FA

Wet Area 89

Tabl

e 2.

21.

(Con

tinu

ed)

Typ

es o

f So

iling

Exa

mpl

eT

ypic

al S

ourc

esC

lean

ing

Met

hods

Dar

k st

ains

Fung

i gro

wth

on

•T

hey

may

be

rem

oved

by

cove

ring

them

with

ful

l-st

reng

thm

oist

ure

film

liq

uid

laun

dry

dete

rgen

t for

a c

oupl

e of

hou

rs a

nd f

ollo

win

gby

spo

ngin

g w

ith w

ater

•If

the

stai

ns d

o no

t com

e of

f, th

ey s

houl

d be

scr

ubbe

d w

ith a

brus

h

Org

anic

sta

ins

Tea,

cof

fee

•A

solu

tion

of 2

0% p

erox

ide

(hai

r bl

each

ing

stre

ngth

) an

d a

few

dro

ps o

f am

mon

ia c

an b

e us

ed to

rem

ove

the

stai

ns

Oil

stai

nsB

utte

r, ha

nd•

The

se c

an b

e ea

sily

rem

oved

by

scru

bbin

g w

ith h

ot a

ndcr

eam

or

dete

rgen

t sol

utio

n or

wip

ing

with

am

mon

ia-d

ampe

ned

clot

hlo

tion

•If

thes

e al

kalin

e so

lutio

ns f

ail i

n re

mov

ing

all t

he o

il, a

stif

fbr

ush

can

be u

sed

(Con

tinu

ed)



FA


Tabl

e 2.

21.

(Con

tinu

ed)

Typ

es o

f So

iling

Exa

mpl

eT

ypic

al S

ourc

esC

lean

ing

Met

hods

Rus

t sta

ins

Cor

rosi

on o

f•

Aco

mm

erci

al r

ust r

emov

er s

houl

d be

use

d to

rem

ove

the

met

allic

st

ain.

The

dir

ectio

ns f

or u

sage

giv

en o

n th

e la

bel s

houl

d be

fitti

ngs

follo

wed

exa

ctly

and

the

solu

tion

shou

ld n

ot b

e le

ft o

n th

esu

rfac

e lo

nger

than

the

spec

ifie

d du

ratio

n. T

his

is to

pre

vent

the

acid

in m

any

rust

rem

over

s fr

om e

tchi

ng th

e til

e su

rfac

e

Aci

d st

ains

Aci

dic

clea

ning

•A

ny a

cidi

c su

bsta

nces

sho

uld

be w

iped

off

imm

edia

tely

with

ag

ents

a w

et c

loth

•If

the

surf

ace

is e

tche

d, p

olis

hing

may

be

requ

ired



FA

Wet Area 91

References

[1] M. Y. L. Chew and N. De Siva, “Maintainability problems of wet areas in

high-rise residential buildings”, Building Research and Information, 31(1),

60–69, 2003.

[2] M. Y. L. Chew, D. S. Nayanthara and S. S. Tan, “Handbook for wet area”,

http://www.hpbc.bdg.nus.edu.sg/, under the segment “About Us” and

“Publication”.

[3] M. Y. L. Chew, Construction Technology for Tall Buildings, 3rd Edition,

World Scientific, Singapore, 2009.

[4] Building and Construction Authority, Good Industry Practices —

Waterproofing for Internal Wet Areas, Singapore, 2001.

[5] British Standards, BS 8204-Part 1: Screeds, Bases and in-situ Floorings.

Concrete Bases and Cement Sand Levelling Screeds to Receive Floorings.

Code of Practice, British Standards Institution, London, 2002.

[6] British Standards, BS 8204-Part 2: Screeds, Bases and in-situ Floorings.

Concrete Wearing Surfaces. Code of Practice, British Standards Institution,

London, 2002.

[7] M. J. Gatfield, Screeds, Flooring and Finishes: Selection, Construction

and Maintenance, Construction Industry Research and Information

Association, London, 1998.

[8] Building and Construction Authority, Good Industry Practices — Ceramic

Tiling, Singapore, 2000.

[9] Building and Construction Authority, Good Industry Practices — Marble

and Granite Tiling, Singapore, 2000.

[10] British Standards, BS EN 12004 Adhesives for Tiles. Definitions and

Specifications, British Standards Institution, London, 2001.

[11] Housing Development Board, HDB Standard Specifications, Singapore,

2003.

[12] M. Y. L. Chew and N. De Silva, “Factors affecting water-tightness in wet

area of high-rise residential buildings”, Architectural Science Review,

45(4), 375–383, 2002.

[13] B. A. Richardson, Defects and Deterioration in Buildings, E&FN Spon,

New York, 2001.

[14] N. L. Mohinder, Piping Handbook, 7th Edition, McGraw Hill, New York,

2000.



FA


[15] D. A. Willoughby, R. D. Woodson and R. Sutherland, Plastic Piping

Handbook, McGraw Hill, New York, 2002.

[16] Building and Construction Authority, Good Industry Practices —

Waterproofing for Internal Wet Areas, Singapore, 2001.

[17] Standards Australia, AS 3740: Waterproofing Wet Areas within Residential

Buildings, Standards Australia International Ltd, Sydney, 1994.

[18] M. T. Kubal, Construction Waterproofing Handbook, McGraw Hill,

New York, 2000.

[19] Singapore Standards, CP 82 — Code of Practice for Waterproofing of

Reinforced Concrete Buildings, Singapore Standards, Productivity and

Innovation Board, Singapore, 1999.

[20] American Concrete Institute, “Guide to the use of waterproofing, damp-

proofing, protective and decorative barrier systems for concrete”, reported

by ACI Committee 515, Detroit, 1988.

[21] P. W. Pye and H. W. Harrison, Floor and Flooring: Performance,

Diagnosis, Maintenance, Repair and the Avoidance of Defects, Building

Research Establishment, London, 1997.

[22] M. J. Gatfield, Screeds, Flooring and Finishes: Selection, Construction and

Maintenance, Construction Industry Research and Information

Association, London, 1998.

[23] Singapore Standards, CP 68 — Code of Practice for Ceramic Wall and

Floor Tiling, Singapore Standards, Productivity and Innovation Board,

Singapore, 1997.

[24] British Standards, BS 8000: Part 9, Code of Practice for Workmanship on

Building Site: Cementitious Leveling Screeds and Wearing Screeds, British

Standards Institution, London, 1989.

[25] British Standards, BS 8000 Part 11.1, Workmanship on Building Sites:

Code of Practice for Wall and Floor Tiling; Ceramic Tiles, Terrazzo Tiles

and Mosaics, British Standards Institution, London, 1989.

[26] British Standards, BS 5385: Part 1, Wall and Floor Tiling. Code of Practice

for the Design and Installation of Internal Ceramic and Natural Stone Wall

Tiling and Mosaics in Normal Conditions, British Standards Institution,

London, 1995.


for the Design and Installation of Ceramic Floor Tiles and Mosaics, British





for Tiling and Mosaics in Specific Conditions, British Standards Institution,

London, 1992.


for the Design and Installation of Terrazzo Tile and Slab, Natural Stone and

Composition Block Floorings, British Standards Institution, London, 1994.

[30] Ministry of Environment, Guidebook for Better Public Toilet-Design and

Maintenance, Singapore, 1999.

[31] Singapore Standards, CP 13 — Code of Practice for Mechanical Ventilation

Air-Conditioning in Buildings, Singapore Standards, Productivity and

Innovation Board, Singapore, 1999.

[32] British Standards, BS-EN 12056-2: Gravity Drainage Systems Inside

Buildings Part 2: Sanitary Pipe Work, Layout and Calculation, British


[33] British Standards, BS 6340: Part 3, Shower Units. Specification for

Prefabricated Shower Enclosures and Shower Cabinets, British Standards

Institution, London, 1985.

FA

Wet Area 93


7566_chap02

Documents

internal wet areas

waterproofing membrane

usedin wet areas

wet area units

entire wet area

various systems

wet area2

small areas