Vegetating the Building Envelope

GREEN WALLS + GREEN ROOFS:

VEGETATING THE BUILDING ENVELOPE

Grace C. Edralin-Servino;

Gloria T. Lava, Ana Cecilia M. Libed; Osias L. Nieva Jr.;

Enrico S. Robles; Edvin C. Santiago; Julieta L. Santos

Graduate Students, Tropical Landscape Architecture Program

University of the Philippines Diliman

E-mail: [email protected]

Mary Ann A. Espina

Associate Professor, College of Architecture

University of the Philippines Diliman

E-mail: [email protected]

Abstract

As buildings continuously replace plants once growing on the ground, our urban

communities are becoming dominated by barren and impervious surfaces that

cause urban heat. To serve as insulation material, plants may be integrated to

the building environment.

While there is a passive way or occurrence of plants growing naturally on

buildings, there are active greening techniques that hasten the plant covering on

buildings such as the application of green walls and green roofs.

Our class was tasked to perform and evaluate several experiments on selected

plant species and materials to come up with modules that are simple,

sustainable, cost-efficient and applicable in vegetating the building envelope as

opposed to the more expensive imported systems being introduced in the market.

Keywords: building landscape, green roof, green wall, roof garden, vertical

garden, vertical landscape, green building envelope, vegetated wall, plant wall,

living wall, living roof, vegetal wall, biowall, green façade

I. Introduction

Trees and other plants which give natural shade, filter air, provide interesting

elements and numerous environmental benefits are constantly threatened by

urbanization and have to compete for physical space with manmade structures.

Designers only include a limited number of plants to enhance their buildings while

building occupants are already content in placing some potted plants inside the

buildings or in some tiny plant boxes outside. Urban dwellers become oblivious or

used to moving about in areas that are devoid of plants. To maximize profit and

cut on maintenance costs, building owners or developers remove or worse, kill

any existing vegetation when converting a land into one of its project

developments. They tend to utilize the whole site as buildable areas and hardly

take into account to leave a patch of land for plants to grow except perhaps on a

small percentage of open space as prescribed in the Building Code. Yet, even

this required open space is not solely devoted to plants and instead used as

paved driveways, pathways, parking and other facilities replacing everything

green with concrete. Designers must be aware of the impacts of the building on

the larger scale. The challenge now for many responsible designers and builders

is to bring back ecological balance that is lost in our built environments. We can

make our existing buildings conducive for plant growth through various greening

techniques. To hasten the plant covering on buildings, green walls and green

roofs are incorporated. They can be installed in many ways depending on several

factors such as site conditions, available materials, budget or technology

available. The concepts, design and choice of materials all contribute to the

success of the project.

II. Green Module Experimentation

For a semester, a class at the UP College of Architecture was required to make

vegetated modules that can be installed on a wall or placed on a roof.

The following activities were done during the first semester of 2008-2009.

Activity June July Aug Sept Oct

site inspection & analysis

research process

green wall experiments

green wall design

green roof design

material procurement

green wall installation +

planting

green roof installation +

planting

documentation

The experiments were documented by the students based on the materials (plant

species, planting media, and container), procedure (installation method,

maintenance requirements and special technologies used) and observations

(advantages and disadvantages).

The choice of container was based on availability, lightness and durability. Plant

species were selected based largely on availability, size, micro-climate,

maintenance requirements and aesthetic appeal. The dry and wet weight of the

module was noted and the cost of the whole assembly was computed.

Observations were recorded and rated from 1 to 5 based on the following criteria:

cost (5 - less costly), durability (5 - durable), simplicity (5 - simple to make),

weight (5 - lightweight), appearance (5 - pleasing), availability (5 - readily

available) and plant growth (5 - healthy plants). The results of the rating were

tabulated with the plastic modules having the highest scores. In the process, the

class identified challenges and recommended solutions to improve the

assemblies.

Criteria Ex.1

(foam)

Ex.2

(plastic)

Ex. 3

(tray)

Ex. 4

(wood)

Ex. 5

(wire)

Ex. 6

(pan)

Ex. 7

(plastic)

Ex. 8

(wood)

Ex.9

(plastic)

Ex. 10

(sack)

proponent JLS JLS JLS GCES GCES AML OLN ECS GTL ESR

cost 5 4 3 2 3 4 4 1 4 4

Durability 5 4 2 3 2 5 4 2 4 2

Simplicity 4 5 5 3 3 4 5 1 5 4

Weight 5 5 5 3 4 5 5 1 5 2

Appearance 3 3 5 4 4 4 3 5 3 3

Availability 3 5 5 5 5 5 5 4 5 4

Growth 1 5 5 2 5 3 5 5 5 5

Installation 1 2 1 5 3 3 2 2 2 1

Total 27 33 31 27 29 33 33 21 33 25

Table 1: Tabulated Rating for the Green Module

The plants which grew well on the experimented modules are the following

Alternanthera cv. (cucharita)

Asparagus densiflorus (foxtail

asparagus)

Callisia fragrans (basket plant)

Chlorophytum bichetii (lourdes)

Cryptanthus bivittatus (star fish)

Cuphea hyssopifolia (false

heather)

Dischidia oiantha (common

dischidia)

Dissotis rotundifolia (Spanish

shawl)

Epipremnum aureum (devil’s ivy)

Nephrolepis exaltata (pako)

Pilea nummulariifolia (creeping

Charlie)

Setcreasea pallida (purple heart)

Tillandsia baileyi (tillandsia)

Rhoeo spathacea (Moses on the

boat)

Zebrina pendula (wandering jew)

III. Site Analysis and Site Selection

Another task was to do a site analysis of an existing building at the UP College of

Architecture Complex, on which a green wall & green roof were to be installed.

The site analysis was based on biophysical information (climate, vegetation,

utilities, building materials, future developments), SWOT analysis (strengths,

weaknesses, opportunities and strengths), site selection criteria. Green roof and

green wall interventions should be placed in an area that will benefit from the

interventions, be visually and physically accessible for students and other

interested professionals so that these demonstration areas will benefit the design

community by contributing to research and promoting sustainable practices in the

profession at large and be easy to access for maintenance workers and future

students.

IV. Green Wall Assembly

Covering about 4 square meters of a wall, the vegetated modules used in the

green wall assembly are composed of 60 pieces of plastic basket (0.31m x 0.22m

x 0.10m) with the substrate covered with filter fabric. The modules are tied by

wire on a steel structural support bolted on the concrete vertical wall. The

substrate is a mixture of 50% coco dust and 50% soilless growing medium. The

plant species used are hardy, requiring full to partial sun, Rhoeo spathacea

(Moses on the Boat) and Chlorophytum bichetii (Lourdes). Other materials used

are garden tie wire and used tarpaulin for wall protection.

V. Green Roof Assembly

The total area of the green roof system is about 29 square meters. The whole

green roof system including the substrate was donated by Ninedots. Some plants

such as peanut plant and carabao grass were donated by Lipa Blooms; other

plants were bought or brought from home by the students.

Materials

Various layers of materials were used providing different functions. The

vegetation layer or growing medium must have a well-balanced structure and

must be light weight. The type and thickness of the substrate soil determines the

plant growth and the structural load for the roof structure. A green roof soil must

be non-compacting, non-clogging, weed and stone free, fire retardant and almost

half the weight of standard topsoil. A filter sheet prevents fine particles to be

washed out of the substrate. A drainage layer retains water in the profiled

troughs. A moisture retention mat is made of non-rotting fiber to retain moisture

and nutrients. It also provides mechanical protection to the root barriers and

waterproof layer. A root barrier prevents roots from touching the slab.

Plant Species

Selected plant species were chosen based on growth pattern, maintenance

requirements and aesthetic appeal.

Acalypha hispida ( acalypha)

Pilea cadierei (aluminum

plant)

Zebrina pendula (wandering

jew)

Chorophytum bichetii

(Lourdes)

Schefflera sp. (five-fingers)

Sanseviera trifasciata ‘Hahnii”

(birds nest sanseviera)

Coleus blumei cv. (mayana)

Neomarica longifolia (yellow

iris)

Phormium tenax (silver wall)

Duranta repens ‘Golden’

(golden duranta)

Dissotis rotundifolia (Spanish

shawl)

Nephrolepis exaltata

`Bostoniensis’ (pako)

Ophiopogon japonicus

(mondo grass)

Euphorbia milii cv. (soro-soro)

Rhoeo spathacea (boat of

moses)

Citrofortunella microcarpa

(kalamansi )

Sanseviera trifasciata laurentii

(variegated snake plant)

Arachis pintoi (peanut plant)

Heliconia (heliconia)

Arachis hypogaea (peanut

plant)

Sansevieria guineensis, 'White

Striped Giant' (white striped

giant )

Coleus blumei (mayana)

Pedilanthus tithymaloides

(zigzag plant)

Chlorophytum capense

(spider plant)

Ctenanthe amabilis (prayer

plant)

Neoregelia 'Fireball' (Fireball)

Paspalum conjugatum

(carabao grass)

Sanseviera trifasciata (snake

plant)

Hedychium coronarium

(kamia)

Weight

The weight load of the roof garden system by Ninedots is 131.13kg/m2. The wet

weight with shrubs is 320 kg/m2. With plants, it is 451.13kg/m2.

Procedure or Methodology

1. Clean the surface as possible, free from any protruding particles. (½ day)

2. Loosely lay the felt layer. (1 day)

3. Hot air weld the layer of PVC waterproofing membrane. (1-3 days)

4. Cover side with PVC sheet using sarna bar and sealant. (1-3 days)

5. Cover with another PVC membrane. (1-3 days)

6. Open holes for the drainage purposes. (½ day)

7. Lay the aqua tray reservoir (½ day)

8. Place the felt filter stabilizer. (½ day)

9. Fill the area with substrate about 2.5” deep. ( ½ day)

10.Grow plants on top. (1-2 days)

Findings

After the green wall installation, the plants on the wall slowly established themselves.

The contrast in color and texture of the Lourdes and the Moses on the boat was

hardly noticeable. The substrate easily dries up and hardens when manual watering

is absent. Lourdes leaves dried up faster than the Moses on the boat.

In the green roof, the planted species increase in number and produced flowers.

75% of the plant species on the green roof established themselves well except for

the peanut plant which dried up on the rear portion by February 2009. The calamansi

which was planted directly in the green roof soil died after a week while the

calamansi in plastic bags are still growing and bearing fruits. In a month’s time,

there are a variety of weeds and new plant species growing on the roof garden. The

maintenance personnel have started growing their own edible plants such as pepper

and tomatoes. Connecting a hose to the nearest faucet has posed a challenge since

the faucet is located 2 stories below.

Green wall and green roof at the UP College of Architecture Diliman

VI. Conclusion

The green wall and roof can be installed in many ways depending on various

factors such as site conditions, available materials, budget or technology

available. The concepts, design and choice of materials all contribute to the

success of the project.

Ultimately, the class has met its basic objectives during the given semester. For

the green wall setup, the whole class decided which type of technology or system

and plants will be applied to the Building. The planting design was finalized by the

class then applied to the chosen site. The structural support was pre-fabricated

outside while the installation on-site was supervised by the class.

As for the green roof system, materials and manpower were provided by a

sponsor, Ninedots, while the planting design and actual planting on site were

done by the students.

As one limitation of the project, maintenance after the semester is not anymore

covered by the class. Most of the students who were part of this class have not

enrolled the following semester or have taken a leave from school. The system

and the plants are left then to the College Administration and maintenance staff.

VII. Recommendations

Lighting System

To enhance the scenic quality of the green roof and green wall at night, lighting

system should be installed.

The figure below represents the proposed lighted area of the building at night.

Irrigation System

As another option for irrigation, a drip irrigation system may be installed both to

the green roof and green wall. Additional hose bibb faucet is proposed to be

installed right below the green roof at the ground level where the main water

Green roof

Green wall

Taken last Feb. 11, 2009

supply in the building is located. A dedicated hose will be connected to this faucet

going to the second floor.

Careful study of slope, soil, water pressure, and types of plants are needed to

determine the most suitable design for the drip irrigation system and components

to be used. Only a conceptual diagram is presented below.

Proposed Drip Irrigation Concept Diagram for the Green Roof and Green Wall

Green Roof Plan Green Wall Elevation

Books

Cooper, Paul. Interiorscapes: Gardens Within Buildings. Octopus Publishing Group

Ltd. London. 2003.

Madulid, Domingo A. A Pictorial Cyclopedia of Philippine Ornamental Plants.

Bookmark, Inc. 1995.

National Parks Board. 1001 Garden Plants in Singapore.

Robinette, Gary O. Plants, People and Environmental Quality: A Study of Plants and

Their Environmental Functions. U.S. Department of the Interior National Park

Service, Washington D.C. 1972.

Undan, Rodolfo C. Urban Agriculture: A Step-By-Step Guide to Successful

Container Farming in the City. Foresight Book Publishing & Distributing Co.,

Inc., Quezon City. 2002.

Yeang, Ken. A Manual for Ecological Design. Wiley-Academy, Great Britain. 2006.

Website

http://en.wikipedia.org/wiki/Green_roof (September 5, 2009)

Brochures

Macro Industrial Packaging Products Corp.

Daku System

Elmich Vertical Greening Module

Resource Persons

Alfredo Roberto M. Cortez, Strategic Business Unit Manager, Ninedots, A Division of

Mega Packaging Corporation.

Manny Y. Macavinta, AVP – Business & Project Management Group, Specserv

Incorporated.

Generoso G. Ignacio, Chief Operating Officer, Jan Owen Martin Construction Corp.

Josephine Munoz, Product Manager, Supersonic Manufacturing Incorporated.

Julie Ann Bacud, Project Development Officer, Supersonic Manufacturing

Incorporated.