Defects and Causes

8/10/2019 Defects and Causes

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Table: 2.1: FOUNDATION BASEMENTS AND DAMP PROOFCOURSE

ELEMENT AND DEFECTS CAUSES

FoundationExcessive Settlement

(Or)Sinking of foundation

Deferential settlement

Over loading of soil due Inadequate width or depth required for bearing

capacit of subsoil and causing higher loadingthan designed one!

Structural alterations such as building used for adi"erent purpose and formation of largeopenings in supported walls causingconcentration of loading on ad#acentfoundations

Inadequate bearing capacit

$ocal variations in soil under foundations%d#oining construction activitiesOver loading and quick sand phenomenon


2/58

&racks and fracture in

'oundation

Di"erential settlement in foundationShrinkage of cla sub soils due to ithdrawal of ground water b prolonged drought *rowing trees nearb Site drainage +unneling $ong time settlement of peat or made up ground

if present under foundation Downhill creep of cla soils if present 'oundation of extension ba s, screen walls laid

with shallower foundations than those of the mainbuildings!

D namic loading on foundations due to earthquake!

-ibrations from. /eav tra0c, 1achiner , 2illingoperations and +unneling operations etc! 'ree3ing of water in upper la ers! 4on provision of expansion #oints below D2& level -e etation rowth and thrust exerted b tree


3/58

ELEMENT AND DEFECTS CAUSESDisintegration of 'oundation

Ba e!ent :Inward bulging of walls

&racks in raft

-ertical &racks

-ertical or on an angle&racks in wall

/ori3ontal and diagonal

&hemical reaction such as sulphate attack oncement concrete'ree3ing and thawing

Excessive lateral pressure due to combined e"ectof active earth pressure and water pressure fromoutsideIncreased pressure on basement walls to(a)2lugging of drains

(b)Excessive rain(c) Inadequate design(d)Submerged soil pressure(e)Drainage qualit of the sub soil

Inadequate design&onstruction #oints not treated4on provision of expansion #oints

Dr ing shrinkageExcessive thermal stresses due to temperature

Deferential settlement of foundations


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&racks in wall

E5orescence

Damp 2roof &ourse.

6ising dampness

$ateral pressure and excessive shear force2oor qualit materials and continuous dampness oralternative wetting and dr ing

2oor qualit materials in D2&2oor &onstruction practices4on provision of damp proof membrane'ailure of damp proo7ng s stemsD2& not wide enough to cover full wall widthDamage caused in D2& while providing service

pipes, etc!8ridging of D2& due to,(a) Inadequate plinth level i!e! less than 9:cm from

D2&(b)&ontinuous external rendering over foundation

and D2&(c) Improper level of ;oor (;oor level above D2&)(d)Dropping and improper ties in cavit walls


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Table 2.2: "ALLS

E$E1E4+ %4D DE'E&+S &%


6/58

/ori3ontal and vertical

cracks

Splitting

Outward bulging of walls

1ovement of wall atD2&

level

+hermal movement due to omission of expansion #oints in long walls'oundation laid on shrinkable cla1oisture movement due to expansion of freshlused bricks in masonrSulphate attack on #oint mortar&orrosion of metal ties if used in wall masonr forstrengthening!

Excessive hori3ontal movement because ofearthquake, Explosion, etc

Displacement of wall through one or more of thefollowing

/igh slenderness ratio i!e! thickness of wallinsu0cient in relation to height

Inadequate lateral support i!e! cross walls or ;oors

not built into the walls to restrain movement! Overloading of structure -ibrations from heav tra0c or machine

Irreversible expansion due to absorption of moisturein new cla bricks and lack of mechanical ke > bond


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Spreading

(Outward displacement ofwall at top)

E5orescence

/ori3ontal cracking of

Inner leaf

8rowing of externalleaf of

&avit walls

2enetration of rainwater

Instabilit

E5orescence onexternal

'ace

Opening in walls $intel ?eather (shades)

Spreading of beam bottom or rafter feet > ringbeam, exerting hori3ontal thrust on supporting wallsdue to non existing of bearing plaster > @raft paper!

2resence of soluble salts in construction material%lternative wetting and dr ing

Sulphate attack causing expansion of mortar in #oints of outer leaf

Insu0cient wall ties or poor qualit ties

8ridging of cavit1ortar debris in cavitall ties wrongl positioned > installed

Incorrect speci7cations&orrosion or absence of wall ties

%lternate wetting and dr ing2resence of soluble salts


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&racks in lintel so0t

Opening of sill frame =oints

&racks in concrete > mortar

Non Load Bea%in# "all in &ll 'anel

&racks at head andsides

B%i() 'anel

Outward bowing

Con(%ete 'anel

Inadequate design&onstruction faultInadequate bearing&oncrete lintel upside down with reinforcement attop instead of bottom (In pre cast lintel)

%lternate wetting and dr ing in case of wooden

ShrinkageImpact damage

Dr ing shrinkage in light weight concrete block >panel

Inadequate support at base De;ection of upper ;oor #oints4ew portion build on old ;oor

Di"erential movement between concrete frame and


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earth quake force!

Over all movement due to 1oisture expansion of bricks 'rost attack of the bricks > mortar Sulphate attack of mortar +hermal movement of roof


10/58

Bounda%+ $all

&ollapse

1asonrdisintegration

all leaning

&racks

Splitting of coping andlifting of top surface

$ateral stabilit not considered in designInadequate foundation2oor bonding of mortar/eight > thickness ratio high4atural calamit -IA, ;oods, earth quake etc


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Table 2.,: "ALL FINIS-ES

Pla te%&ra3ing of surface

$arge cracks

&ontinuous cracks in

plaster at #unction of slab >

Dr ing shrinkageShrinkage of substrate light weight concrete

Di"erential movement of structural members&racking of substrate due to settlement of

foundations and external vibrations

4on provision of groove in plaster6otation of #unction and de;ection of roofs slab >


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beam and wall

&racks at the #unctionof

di"erent substrate material(e!g! lintels, &olumns andembedded pipes)

2itting or browning in

lime plaster

'laking

'laking of 7nishingcoat


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8ulging of ceilingplaster

E5orescence

Pointin#/ollowness and

erosion of

mortar

Rende%in#

De bonding and cracks inrendering

Excessive de;ection > vibration in substrateDe bonding due to moisture penetration at theinterface of substrate

%lternative wetting and dr ing2resence of soluble salts in plaster mix

poor mortar mixSevere climate wind driven rainstorm, ;oods etcDetachment of earlier pointing from the substrate'ree3ing and thawing$ong term aging of mortar

Inadequate bound to wall faceeak > mortarDi"erential movement of substrate

+ransfer of cracks from substrateShrinkage rendering of mortar&ontamination resulting in high shrinkage


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/ori3ontal and-ertical

&racks in rendering

Claddin#Displacement and

cracking

of cladding

Table 2. : C-MNE/ STAC0 AND S-AFTS

C i!ne+ ta()

&racking, splitting and

bending

Damp penetration

Sulphate attack%lkali aggregate reaction in background material

Inadequate bond > adhesion with baseDi"erential movement of substrateShortening of individual beams and columns of 6&frame due to shrinkage, creep and loading

$oss of adhesion due to bending of base structure

&ondensation of the water vapour in the ;ue gasesresulting in water migrating in to the walls of thestack causing mortar expansion

Exposed stacks not weather proof 'lues open to roof space > ;u opening not coveredD2& in chimne absent or wrongl placed6oof plastering incorrectl detailed


15/58

Staining of chimnebreast

Se% i(e a3t

In sanitar condition

'lues not vented and condensation leaking from ;uein to brick work6oom ventilation inadequate/igh di"erential temperature inside and outside1asonr and ;ue liner not #ointed properl'lue terminal unsuitable

Design fault B $ack of drainage1isuse of access$ack of suitable access8irds and insect breeding/uman factor B throwing of litterIn sanitation and damp condition


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Table 2.4: COLUMNS AND BEAMSColu!n&racks

Spalling

&rushing of columns

8uckling

Defective lift #oints

=oint failures

Bea!&racks

Shrinkage cracksDi"erential temperature&orrosionExcessive loading

&orrosion &arbonation or &hloride attack2h sical damage

Excessive loading be ond compressive strength ofconcrete

Inadequate designExcessive slenderness ratio

2oor workmanship

Inadequate designExcessive beam reaction > shear force8earing failure

$ateral ph sical impactShrinkage

Inadequate design +hermal movements


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Spalling

&rushing of bearing

Excessive de;ection

$ateral bulging

Table 2.5: ROOF AND ROOF TERRACES

Flat Roo3

&racking

&orrosion of reinforcement

Inadequate bearing surfaceDesign or construction failure

Excessive span > e"ective depth ratioExcessive loading$oading pattern and load positions

De;ective workmanship

Excessive lateral loading unaccounted in design2oor form work

Shrinkage in concreteEnd > support conditionsIncorrect placement of reinforcement Inadequate designImproper mix design Inadequate compaction and curingDela in providing weather proo7ng courseDi"erential expansion of hidden conduit pipes


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Spalling

De;ection

&rushing of bearing

Shearing failure

&orner lifting

2onding

'ree3ing and thawing &orrosion of reinforcementSulphate attack

Over loadingImproper design high span > depth ratioImproper construction practices i!e! 2oor form workof Excessive cover provided

Inadequate bearing areaInadequate reinforcement at bearingSimpl supported bearing against continuoussupport conditions

Inadequate design details for shear force

Inadequate design/arsh initial dr ingExcessive bending and de;ection

Inadequate slope and drainageInadequate design of rain water pipe8lockage of the drainage s stem


19/58

Pit( ed %oo3

Sagging > anddeformation

Sagging of purlins and

rafters

Slipping roof tiles andslates

Inadequate design of frame and its #ointsDeterioration in strength of structural members'ailure and excessive bending of purlinsOverloading$oad of the roof causing the spread of the outerwalls/ori3ontal movement at feet of rafters8earing wall plates not properl secured to the wall6emoval of support purlins and internal struts


20/58

=oint failures

1ould growth,corrosion

and rot in roof spaces

Ceilin# 'la te%&racks

$oss of adhesion

Ce!entitiou $ate% '%oo&n# S+ te!

Improper bond

&racks

Inadequate provision for ventilation$eakage and dampness2assage of water vapour and gases into the roofspace from inside&ondensation in roof space

ShrinkageDe;ection of structural substrate panels2h sical impact

eak undercoat +oo smooth substrate of roof slab%bsence of mechanical ke

2oor surface preparationImproper primer and bonding material

+ransmission of substrate cracks2oor crack bridging capacitExcessive deformation and stresses in substrate


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Deterioration

Li6uid Me!b%ane

8listering

Deterioration

Fa(to%+ '%odu(ed !e!b%ane

'olding and ridging >

6ipping

8listering

Embrittlement of the

membrane and tearing e"ect

$oss of adhesion$eakage


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Pol+!e% Roo&n#

$eakage

Splitting

Fe%%o(e!ent

&racks

Da #oints

De bonding

B%i() bat Coba&racks

2ressure on blister or folded surface resulting incracks and openingsInadequate provision to isolate felt from buildingmovement

Inadequate bonded #oints2uncture of pol mer sheet

1echanical damage b dropping of stones, nails andtools on 2ol mers!

Shrinkage (6ich cement mortar)

&orrosion due to improper coverInadequate curing

4on provision of bonding agent

2oor surface preparation

Improper detailing of construction > da #ointsShrinkage of mortarInadequate curing


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Li!e te%%a(in#&racks

8listers

Mud3u ) aOpening of surface #oints

2onding

$ifting of tiles

4on provision of 7llet&racks alon the eri her

4on provision of 7llet at #unctionsInadequate maturing of limeInadequate provision of supplementar materialslike fenugreek powder, *ur water, 7bers etc!

Inadequate slacking of limes

Shrinkage and thermal movements%brasion/uman activities

Improper drainage slopeImproper maturing and compaction of mud

Inadequate supplementar materials like natural7bers, crude oil etc

Ingress of water below tilesDe bonding of tiles with base mud mortarEvaporation of locked moisture

+ile #oints not sealed with proper mortar


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Deterioration of tiles

IPS7 Mo ai( 7 StoneFloo%in# 8U ed 3o%a((e ible Te%%a(e 9

&racks and opening of

=oints

8reaking of ;oorseparators

Table 2. : FLOORS AND FLOOR FINIS-ES

Slab on #%ade

&hemical action due to environmental pollution

+hermal movement (Expansion > &ontraction)Shrinkage1echanical impact2oor compaction of bed mortar

/uman activities%lternative wetting and dr ing


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8ulging

&racks

=oints edge breaking

Shrinking of ;oor >

&ollapsing

etting of ;oor

$ifting > curing

Swelling of soils

Incorrect speci7cation of mixInadequate thickness of screed

Deformation of base and sub bas eInadequate curingSlab sub#ected to harsh initial dr ing4on provision of contraction and isolation #oints$arge si3e ;oor panels

Deterioration of ;oor separators > strips

Design failureImproper compaction of sub base

$eakage in buried pipesImproper mix usesInadequate curing

Sulphate attack

'loor laid in too large ba s2oor workmanshipDefective > deteriorated lean sub base concrete


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U''e% Floo%

De;ection in slab

Spring ;oors

depth ratio)

Incorrect #oint length2erimeter support omitted

In su0cient insulating media, inadequate isolation >resilience against impact and sound

2oor bond to base concrete especiall when old

concrete not been cleaned, hacked and wettedbefore la ing ;oor 7nish


27/58

De bonding of topla er

Spalling at #oints

Disintegration of ;oor

Separators

Linoleu!

Irregular surface

Fle


28/58

De bonding

Scu" marks onsurface

Rubbe%Surface deterioration

Ce!ent (on(%ete 7 Te%%a;;o Stone 7 Ce%a!i( tile

%rching and lifting

De bonding

Surface deterioration

"ood tie

2oor surface preparationImproper use of bonding material

8lack rubber in foot wear, caster wheels > t res

&ontact with oil ;ats and greases1echanical deteriorationeathering e"ect

Dr ing shrinkage of base screedExpansion of tiles due to moisture absorptionDi"erential thermal movement of concrete base andtiles

2roof surface preparationImproper use of bonding material

%ttack of solvent based cleaners and chemicals2h sical wear and tear


29/58

Staining and lifting of tiles

Industrial ;oor 7nishesCon(%ete >oo%

8listering

&ra3ing

6ising damp from ;oors causing expansion of tilesOmission of expansion strip around perimeter ofareaInadequatel seasoned tilesc ratio in mixExcessive bleeding and rapid dr ing


30/58

&urling and wavsurface

Dusting

Disintegration

+op concrete cools while the lower la er remainswarm6apid shrinkage a top than at bottom due todi"erent rate of dr ings

+he concrete beneath the surface was not hardenedbefore 7nishing6apid dr ing due to Sun, ind or low humidit% cold sub grade or a retarder dela ed settingbelow the surface

+he cracks bulged from beneath as the powertrowel is moved across the slab

+he concrete surge ahead of the screed was notkept uniform

Excessive presence of free lime in concrete matrix&hemical action &oncrete surface dries without hardening

%brasionImpact damage'ree3ing and thawing


31/58

2lastic shrinkagecracking

(&racks that occur before the concrete sets)


32/58

Indentation

Slipperiness


33/58


34/58

$oosening >Deterioration

of individual members

&racking ? softening

Deterioration

"indo$ and doo%

Door sticking

2in holes

Excessive pressure on #oint 7xtures #ointing failures2oor workmanshipExcessive moisture content in wooden members

Dr and wet rot4ailing or 2h sical impact

4on provision of protective coating especiall on theface in contact with masonr Dr and wet rot in timberInsect > termite attack&orrosion on steel frames8imetallic action on aluminium frame exposed toenvironment

arping of thin or insu0cientl seasoned woodInadequate hinge support or loosening of hinges

8eetle infestation and wet > dr rot


35/58

Deca ed windowboards

De lamination of pl wood

panel

Damp penetration under sillOmission of D2& under sill&ondensation

Inadequate protection against moistureInappropriate speci7cations


36/58

Table 2. : DECORATI=E 7 PROTECTI=E FINIS-ES

Paint &l!

8listering

8leeding

8looming

&halking

&ra3ing

&urtaining andsagging

Entrapped moisture forces the paint into littlebubbles or blisters

+he resinous deposits of the sub surface coming tothe surface of paint cause bleeding

1ist ha3e or milkiness due to presence of moistureor chilling of surface glass coat

2owdering of the surface paint due to externalexposure and lack of paint binder

Irregular cracking of surface due to use of harddr ing paint with thick consistenc


37/58

'laking > peeling andcissing

*rinning

*illing

$oss of gloss

1ould


38/58

Stick 7lm

Table 2.1 : SER=ICES

Pi'e $o%)

%lkali attack b salts in backing


39/58

$eaking pipes

$eaking #oints

ater hammer

6upture of pipe

Ta' and Sto'(o()

&orrosionExternal damage due to vibrations and bumping'ree3ing and thawing

earing out of glandExternal damage2oor installation8imetallic corrosion when dissimilar metals used&hemical action of ;uxes

+hermal expansion > contraction due to hot and coldwater circulation

Sudden increase in pressure in the s stemater hammer in cold pipes caused b loose washerplates in valvesC@nocking in hot water pipes caused bobstructions in the ;ow in return pipesSudden closing of traps

'ree3ing of water in pipes resulting in volumeincrease


40/58

ater leaks aroundtop of

spindle

Drips when closed or

vibrates when opened

Ball al e

Discharge fromover;ow

Sticking in closedposition

Inadequate ;ows

/issing noise

Sto%a#e (i te%n

'ault gland packingDefective handles of stem

+he washer has deteriorated or broken +he seat is worn and pitted$oosening of washer from the seat

'ault washer or worn valve seating +hreads of spindle worn out

-alve fails to close properl due to fault washer, oreroded seating or presence of grit or lime deposits


41/58

Over;ow

ater ;owingcontinuousl

ater not ;owing

&istern fails to 7ll

6ust pitting of galvanised

steel cisterns

&orrosion of 7ttings

attached to cistern

Distortion of 2-&cistern

2lunger washer worn out'loat valve broken or deteriorated'loat valve defective

'lush valve defectiveDeformation of rubber valve or valve not seatingproperl

8ell > siphon t pe arrangement out of alignmentOperating lever defective

Defective ;oat valve (plunger #am)

Electrol tic action due to iron 7lling from drillingholes left in tank or deposition of copper from water

into sides of tank

8imetallic action with 7ttings of brass or othercopper bearing allo s!

Inadequate base support


42/58

D%aina#e

"ate% 'i'eSoftening and

distortion

8locking

T%a'

$eakage

&logging

'oul smell

Unde%#%ound 'i'e

8lockage

%geing6eaction with chemical cleaners

Internal corrosion/ousehold waste

'ault plumbing8od crack

%ccumulation of grease, dirt and other materials i!e!hair and lint etc

ater seal broken due to evaporation and dr ing

2oor la out (pipe runs not in straight line betweenaccess points of laid with insu0cient slope to clearsoil)Drain fractured b settlement, heav tra0cs ortrees roots%ccumulation of builders rubbish s duringconstruction


43/58

'ailure under tests

Tan)

O e% ead 7 Unde%#%ound

Over;ow > no ;ow

$eakage

Se'ti( tan)

'loating sludge

Defective #oints at. 8ase of soil pipe Entr to manhole Intermediate point

Drain fractured &racked ;aunting in manholes

'loat valve not functioning

'ault plumbing,&racks in tank bod%lternate wetting and dr ing

Sludge decomposition due to long travel


44/58

'oul smell

Table 2.11: MATERIALS

Ti!be%

Deformation

6ot in structuraltimber

Septicisation of sewage due to long travel time insewer line2resence of sewage solids and plant growths

Detergents used in the household washing causes

Seasonal moisture movement of timber at the end

Dr rot due to ingress of water through defectivecoverings or condensationet rot when moisture content of timber is more


45/58

Deca > deterioration

B%i()

hite powderingdeposit

Staining of bricks

Deca (Disintegration)

Stone

Staining (organic)

Staining (metallic)

Insect > termite attack&ontinuous dampness

E5orescence caused b cr stalli3ation of solublesalts in bricks or mortarSulphate attack

E5orescenceDampness%bsorption of chemical salts

&r stalli3ation of salts formed below the surface inthe brick crevices, these cause surface erosion andknown as &r pto ;orescence! hen cr pto;orescence continues identi7ed it leads to thedeca of bricks

2resence of alkali in mortar, cement and h drated

1etals attached to stone


46/58

2itting and staining of

limestone

Deca of sandstone

Delamination of surface

la ers

Erosion of surface

&ontour scaling

8listering of surface

Con(%ete

&racking

2opout

&ontinuous dampness

&ontinuous dampness

2enetration of rain water with subsequent disruptionof surface of free3ingSulphate attack from soluble salts in backing or

eathering e"ect (stone soluble in rain water

containing carbon Dioxide and sulphur dioxide)

6epeated alternate repeated wetting and dr ing ofthe stone which leads to di"erential conditions in

%tmospheric pollution sulphur dioxide absorbed inthe rain water to form a weak acid solution which

attacks the natural binding medium of the stone

&hemical reaction +hermal expansion and contractionOverloading or overstressing&orrosion

Excessive presence of soluble salts


47/58

2ermeabilit

eathering of

concrete

&arbonation

Discoloration

Surface damage

Deterioration

2oor mix design, higher >& ration and impropercuring

%tmospheric pollution rains and acid rains

2h sical abrasior&hemical attackSolar radiation

Environment pollution2orous concrete4on provision of sealer coat

Environmental pollutionind driven rains

&oncrete surface can be damaged b 1echanical impact or abrasion


48/58

/one combing

Spalling

Dusting >

delamination

Disintegration

R.C.C

Insecure from work which allows the leakage orbleeding of plastic concrete, especiall the cementcontentImproper compaction and insu0cient consolidation

'rost damage'ire damage&orrosionSulphate attack

8uild up of water and air beneath a dense la er of

surface mortar resulting in de lamination

&hemical reactionSulfhate attack 'ault mix designImpurities in materialsIncorrect construction practices


49/58

'ailure of coverconcrete

Mild Steel

6usting > &orrosion >2itting

-i# St%en#t teel&orrosion

Co''e%2itting &orrosion

Alu!iniu!

2itting &orrosion

&over concrete weak and porous unable to resistexpansion forces caused b

&orrosion of rebars Di"erential thermal expansion 1oisture ingress 'rost action

Exposure to atmosphereExposed to moisture > polluted air

Stress corrosion

%ttack b ;ue gases containing sulphur dioxide&ontact of carbon with copper

6ain water draining from copper covered roofs anddepositing small particles of copper on aluminium

+he presence of copper together with dampconditions caused b heav and repeatedcondensation lead to serious corrosion


50/58

&hemical corrosion

8imetallic corrosion

Lead&orrosion

in(&orrosion

A be to S eet&racking and breaking

Deterioration

*al ani;ed I%on S eetDeterioration

Steel and presence of

%ttack b free alkali present in concrete > mortar

Exposure to sulphur gases and compounds

Sub#ected to more pressure due to overloading

Impact damage

1oss and lichen growth cause surface deterioration%tmospheric pollution

&orrosion of basic material%geing and atmospheric pollution&orrosion of nails and wind action


51/58

T at(

Deterioration of thatch

6ipping o"

Fib%e Rein3o%(ed Pla ti( S eet

&racks near = bolts

Deterioration

*la

&racking > breakage

%geing and atmospheric pollution /eav rains and winds6at eating and bird habitation

+ermite attack

/eav wind > stormImproper securing of thatch

$ess tearing strength

%geing and


52/58

Table 2.12: DAMPNESS IN BUILDIN*S

Foundation

Damp patches nearplinth

below D2& visible onexternal during rainseason

Ba e!ent

%bsence > failure of vertical water proo7ng s stemaround foundation&ollection of water ad#oining the foundation areasand impervious soil strata'ailure water proo7ng equalities of foundations


53/58

Dampness is visible onwalls and ;oors! In servecases water ma be leakingor seeping through walls or;oors, or ma be collectingin low level areas

"all

Da!'ne at o% nea% #%ound le el

Semi permanentdampness

2enetration of water under pressure throughconstruction #oints > &racks > 2orous structures1oisture penetration from sub soil through crackedbasement walls > raft slabInadequate water proo7ng s stem'ailure of water proo7ng s stem due to(i) Deterioration with age(ii) $ack of continuit of water proo7ng s stem

e!g! not carried under stanchions and otherstructural members which ma penetrate thewater proo7ng s stem

(iii) Damage occurring during construction

4on provision of perforated pipe damage around theperimeter of the basement&ondensation! +his is likel to arise when heating isused intermittentl without adequate ventilation

+his t pe of dampness is due to one or more of thefollowing.(i) $ack of a damp proof course(ii) 8ridging of the damp proof course(iii) 'ailure of the damp proof course


54/58

can be seen on wallsurfaces from groundlevel up to approximatelH:Fmm or even higher insevere cases! Decorationsma be damp, blistered anddiscolored or dried out and pushedo" the wall b a salt deposit! +here mabe rot in ;oor and skirting boards ad#acent to the deteriorated wall!

E


55/58

Inte%nal $all2atch damp areason

plaster work, accompaniedb peeling of wall paper,discoloration or, surfacestains or mould growth

2atches of dampoccur

particularl in kitchens andcold bathrooms! 1oisturebeads appear on thesurface of dense materials

O'enin# in $all

Damp patch overhead of

opening

Damp patches around

$eaking or possibl back 7lling over;ow pipes$eaking pipes embedded in the wall causing frostdamage or corrosion$ocalised chemical action $ocalised condensation over buried rising main

&ondensation of water vapour in the air in contactwith cold surfaces

&ondensation of moisture vapour with in the bod of the wall6esidual > construction water

Inadequate design (Drip > throating missing or partlconstructed)%bsence of gola > 7llet at intersection of wall andlintelOmission of cavit tra over opening incavit wall ortra too short causin dam ness in corners

Omission of vertical D2& at #unction of inner andouter leaves or window > door frame


56/58


57/58

#unction and then spreadsdownloads, pronouncedafter heav rain or snow fall!

Unde% ide o3 >at %oo3Damp patchesvisible after

rain and in winters aroundthe perimeter of the roof!

Pit( ed Roo3Damp patches seenon

'alse ceiling after raining orsnow fall

Solid #%ound >oo%

&ondensation of water vapour passing from theroom below ceiling into the structural roof slab!6esidual construction water entrapped during roofla ing and drips slowl !Direct rain penetration and it travels hori3ontallbetween roof slab and felt!ater dripping from cracks in ceiling or aroundelectric 7ttings

Inadequate laps or nailed through troughs instead of crowns of corrugationsDefective tiles or slatesDefective battens to which tiles and slates areattached (wood worm or fungal attack)Defective parapet or valle gutters$eaking water tank


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Defects and Causes

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