Aa project1 fine

Asian Architecture [ARC 2213/2234]

PROJECT 1: CASE STUDY

The Use of Different Architectural Roof Designs Which Provide Thermal Comfort in

Phase Two Residential Area, Belum Rainforest Resort, Pulau Banding

NAME: FAM LI KIAN

STUDENT ID: 0310639

LECTURER: Ms. Nurul Alia

SUBMISSION DATE: 11 November 2014

The Use of Different Architectural Roof Designs Which Provide Thermal Comfort in Phase Two

Residential Area, Belum Rainforest Resort, Pulau Banding

ARC2213/2234 Asian Architecture | 0

The Use of Different Architectural Roof Designs Which

Provide Thermal Comfort in Phase Two Residential Area,

Belum Rainforest Resort, Pulau Banding

Table of Contents Page

Abstract ............................................................................................................................. 1

1.0 Introduction ........................................................................................................ 2

2.0 Climatic Responsive Roof Design ..................................................................... 4

2.1 Thermal Comfort ............................................................................................ 4

2.2 Tropical Roof Design Principle...................................................................... 5

3.0 Application of Roof in Phase 2 Residential Area ................................................... 6

3.1 Roof Design in Kampung Villa ...................................................................... 6

3.2 Roof Design in Deluxe Suite .......................................................................... 8

3.3 Overhead Shading Devices .......................................................................... 11

4.0 Weakness of the Existing Roof Design ................................................................ 12

5.0 Recommendation .................................................................................................. 13

6.0 Conclusion ............................................................................................................ 14

7.0 References ............................................................................................................. 15




Abstract

In a tropical rainforest, the average temperature is comparatively higher than

other climates. As roof being one of the most prominent building structures that is

directly exposed to sunlight where heat gain happens. The purpose of doing this

research paper is to study different types of roof designs used in Belum Rainforest

Resort and how did the designs influence the effectiveness of it in providing thermal

comfort to the accommodated users. In order to enhance the process of research to

support the proposed topic, literature reviews information have been gathered through

different sources regarding the types of roof designs which are responding to the

tropical climate. There are two main types of roof designs used in the Phase Two

residential area, which are the timber pitch roof in the Kampung Villa and the concrete

flat roof in Deluxe Suite. Besides, there are also a few types of overhead shading

devices at the rooftop terraces. Roof provides enclosure to a space by preventing the

entry of heat, wind, and precipitation and also to resist different thermal condition.

Hence, the geometry and materiality are important in controlling the air flow,

ventilation and heat gain of a roof into a space. Through study, lightweight materials

and steep pitch roof are preferably to be used in Belum Rainforest because it absorbs

less heat and suits the high rainfall condition in a tropical climate, which is similar to

the timber pitched roof in Kampung Villa. Although the concrete roof used in Deluxe

Suite is less responsive towards the climatic condition, the spaces above was fully used

as terraces with the use of vegetation as shading devices for the roof. The weaknesses of

both roof designs will further be studied in order to provide better suggestions to

improve the living quality in the residential area. In conclusion, both type of roof are

climatic responsive. Different design approaches can always improve a roof to suits the

site where it is going to be built.




1.0 Introduction

Belum Rainforest which located at Pulau Banding, Perak, is one of the most

significant rainforest in Malaysia. Belum Rainforest Resort is not only famous for

holiday vacation but also its beauty where the resort is surrounded by such rainforest

and a man-made lake, Tasik Temmengor. Generally, the climatic condition in Belum

Rainforest is tropical climate, where the areas involved will be in hot and humid over

the years. Therefore, this unique climatic condition has some relevant factors that could

affect a building’s design and construction. For instance, the difference of temperature

in day and night, the humidity condition, and the solar radiation.

The resort is currently zoned into two phases where the construction of second

phase, the most recent phase has just been completed in 2013. In phase 2, there are two

parts of residential areas, the Kampung Villa and Deluxe Suite. Although both

residential areas are located in the same phase, they show two different design styles

which speaks their own unique language. Firstly, the Kampung Villa was constructed

by timber planks which adapted more traditional design style. In the other hand,

concrete was used in Deluxe Suite construction with the free grow of creeper plants

over the building.

But there is one sameness in the intentions of the designs which is to provide

comfort to the users by incorporating with different considerations such as climate

condition. As the climate in Malaysia is tropical rainforest climate, roof is considered as

one of the prominent building envelope which are able to influences the users comfort.

The design consideration of roof is not just about the form and geometry, but also its

effectiveness in responding to this tropical climate condition.




Figure 1.0: Belum Rainforest Resort plan indicating different phases in site.

This paper will be investigating different types of roofs used in Phase 2 resort and

supported with types of overhead sun shading device in order to provide thermal

comfort to the accommodated users. The topic will be supported by following few

questions:

1. What is the importance of roof and how does different roof designs respond to in

providing thermal comfort?

2. What are the design consideration that have been taken into the roof designs in

Phase Two of Belum Rainforest Resort?

3. How does the design consideration applied provide thermal comfort and do they

maximised their full potential in providing comfort?

4. What are the problems of the designs faced in consideration with the local

climate condition?

5. What are the suggestions to resolve or to improve the problems mentioned?

Phase 1

Phase 2




2.0 Tropical Roof Design Principle

2.1 Thermal Comfort

ASHRAE (Standard 55, 2013) defines thermal comfort as the condition of mind

that expresses satisfaction with the thermal environment. In order to feel comfortable,

human must maintain an internal body temperature within a range of 36.5-37˚C (Koch-

Nielsen, 2002). Factors that could affects a human’s comfort state could be his or her

metabolic rate, involuntary control mechanisms, and some external influences such as

surrounding air temperature, clothing level, muscular activity and different locations.

Hence, a design of a building which consider about the factors that affect thermal

comfort is very important in order to adapt the idea of provide a better living spaces

quality. For example, when it is too hot, shades and fluent air movement should be

taken into consideration so that body can lose heat by radiate heat to the surrounding.

Same goes to the design of roof, it is important to select the right design in order to

reduce the heat gain of roof and to maintain the thermal comfort.

Figure 2.1: Heat transfer schematic diagram between human and the surrounding environment which

affect the thermal comfort (source: http://www.scody.com.au).




2.2 Tropical Roof Design Principle

As roof facing vertically towards the sky, it has to bear with highest light and heat

intensity. This is why roof is considered as such a prominent building structure which

should be wisely designed in order to sustain the pressures from different thermal

condition in tropical climate. In short, the design of roof should seek for the needs of

reducing solar radiation absorption and its effects to the indoors comfort level. Hyde

(2000, p137) stated that the roof design of buildings is a complex problem of attempting

to provide a form of enclosure that resists the forces of nature – wind, precipitation and

thermal conditions. The functions of roof included to provide protection to the interior

spaces against heat and solar radiation exposure, to protect the building against

precipitation such as rainwater and snow, and last but not least to ensure smooth flow of

air movement across the roof surface and ceiling space.

There are a few principles that could be applied in order to enhance the

effectiveness of functions mentioned. One of the main factors is the geometry of roof.

Firstly, pitched or sloped roofs are usually recommended, especially when a roof is

required to withstand unexpected tropical thermal condition showers, such as strong

wind and precipitation due to the high rate of rainfall in such climate. It also helps in

reducing the heat absorbing surface, which will relatively reduce the heat gain. Besides,

the roof angle of a pitched roof creates a space in roof and this allows the exchange of

air and ensure well ventilation in the building.

Figure 2.2: The direction of air flow through the pitched roof which draws the heat gain on the roof

surface away (source: Gut and Ackerknecht, 1993).




In the other hand, the materials used in a roof construction is also one of the factors

that could affect heat gain. Lightweight materials such as bamboo, timber, and atap

leaves are preferably used in houses in tropical climate because they have very little

thermal mass. This property of them reduce the amount of heat accumulated in day time

and also minimise heat radiates back at night.

Lastly, some minor design element such as the reflectiveness of surface is useful in

reflecting the solar heat gain. Hence, white or light colour of material are preferably to

be used for roofs in tropical countries. Besides, an addition shading elements or

insulation such as landscape shading could also reduce heat absorption of a roof.

3.0 Applications of Roof in Phase 2 Residential Area

The residential area in Phase 2 is divided into Kampung Villa, a much more

traditional design and Deluxe Suite, a comparatively modern design in the entire resort.

Both of the areas are very contrasting although they have the same intention in design

which is to provide comfort shelter to the users.

3.1 Roof Design in Kampung Villa

4.0 Figure 3.1.1: White timber planks pitched roof used in Kampung Villa.




In Kampung Villa, pitched roof is used and it is made of timber planks which have

been painted in white. This characteristic of pitched roof used matched the requirements

of roof design in such tropical climate since it promotes occurrence of good ventilation

to keep the building cool.

Phase 2 is much more exposed to the sun compared to Phase 1 due to the less

amount of vegetation and the sloping landscape contour condition, this pitched roof

design with a roof angle of 21˚and 51˚ is very suitable in reducing heat gain of the

houses in Phase 2. But it is a ceiling along roof design where no air could be trapped in

the space above the ceiling.

Figure 3.1.2: The wind pressure happens according to the wind direction (source:

www.buildingscience.com).

Figure 3.1.3: The wind direction passing over Belum Rainforest Resort in different wind seasons.

http://www.buildingscience.com/




In another hand, the wind direction could affects the wind pressure that will later

be applied on the roof, the roof slope should generally be orientated towards the

prevailing breezes, and obstructions of the air movement should be avoided (Koch-

Nielsen, 2002). In Kampung Villa, the roof slopes are all orientated facing towards the

prevailing wind from the direction of Northwest and Southeast according to different

monsoon seasons. This helps in improving ventilation in the space and also resists wind

pressure better. As provision of fresh air supply can also contribute to the thermal

comfort, the spaces beneath the roof can ensure well ventilation of air flow passing

through it and hence cools down the interior spaces. Ventilation in roof not only

involves in removing internal heat but also reduce the air humidity in the roof space

through roof openings which may also be driven by prevailing wind or thermal

buoyancy, such as stack effect (Yannas, Erell and Molina, 2006).

Besides, timber is a lightweight material where it has very little thermal mass.

This prevent the roof structure from storing excessive heat during the day time which

will later warm the building up. The white colour paint painted on the timber planks

surface is one of the important element to reflect solar radiation as well due to its high

reflectiveness. This choice of material has actually helps in reducing the heat gain of the

spaces in order to provide thermal comfort to the users accommodated.

Hence, it could be concluded that the duo pitched roof design in Kampung Villa

has actually shows many concerns in order to be climatic responsive and to provide

comfort to the users.

3.2 Roof Design in Deluxe Suite

The roof design in Deluxe Suite is flat concrete roof. But the concrete roof slabs do

not perform in acceptable level in tropical countries and tend to absorb heat easily




which will later emits heat radiation to the occupants in the space. If the design of

ceiling and air cavity of heavyweight roof did not incorporate with such thermal

condition, excessive heat gain would occurs due to the fully exposure of flat roof to the

solar radiation. Besides, the use of concrete often lead the flat roof to failure such as

cracking issue due to the expansion and contraction.

Figure 3.2.1: Flat concrete roof used in Deluxe Suite.

Besides of over exposed to solar radiation in daytime, the cool temperature will

remains in the roof surface in night due to its increased density. The properties

mentioned shows that such heavyweight material and such roof design is not a wise

selection to be applied in the resort tropical climate since it does not provides thermal

comfort to the occupants.

But in consideration of design intention, the architect proposed this design is

because he wanted the occupants to enjoy such breath taking views of Belum Rainforest

and to make the design blends into the site. Hence, the spaces above Deluxe Suite is

fully utilised as an open roof terrace. This is considered as one of the advantages of a

flat roof, by adding parapet wall surrounded the roof, a new functional space is created.




Roof terrace provides not only a space but also helps in conducting cool air into the

interior spaces and increase the cooling process further. An extra layer of timber

decking above of the concrete roof has somehow acts as a walking platform and also a

buffering layer to reduce direct heat gain of the roof since timber is a comparatively

lightweight which absorb less heat. Light colour surface of the timber decking can

reflects solar radiation away as well. This has turned the use of flat roof into such wise

selection by just adding a small element onto it.

Figure 3.2.3: The roof top of concrete flat roof in Deluxe Suite which has been used as a roof top terrace.

Lastly, in comparison to the pitched roof, flat roof does not face a big issue in

placing its orientation according to either the sun or the prevailing wind. This is because

the form of it does not creates extra roof space in between. Hence, there will be no

major effects on the ventilation, air changes and less wind pressure will be applied on it.




Figure 3.2.2: The wind pressure happens according to the wind direction (source:

www.buildingscience.com).

3.3 Overhead Shading Device

Since an additional functional space is added on top of the flat roof of Deluxe Suite,

the space is considered occupied, and the comfort level while using the space should

also be taken into consideration. Hence, appropriate overhead shading devices at the

terrace is considered as an important structure which help in improving occupants living

quality, especially in providing shades from the high sun. There are two major types of

overhead shading that could be found in Phase 2.

Figure 3.3: Types of overhead shading devices used at the rooftop terrace.

http://www.buildingscience.com/




The first design is to use vegetation such as plants and creepers as buffer layer.

This approach can ensure the free flow of ventilation and allow the penetration of

sunlight into the space but preventing the entrance of precipitation through a transparent

layer. Vegetation is a very good barrier to reduce glare, noise by sound absorption and

also dust. In the other hand, the evaporation from plants leaves keeps the temperature of

the shades lower than surrounding air temperature. Besides of providing comfort, it

helps in enhancing the aesthetic value of the space by creating a sense of green which

blends with the surrounding as well.

The second type of overhead shading device is more enclose. It speaks the same

language as the roof itself as it is made out of concrete. This enclosure provide not only

shelter to the users but also the services equipment such as electrical wires and lighting

equipment. But in order to provide sufficient sunlight to the space, skylight is applied.

These overhead shading devices do play a very important role in providing thermal

comfort to the occupants from direct solar radiation and rainfall while they are in such

an open terrace.

4.0 Weakness of the Existing Roof Design

As mentioned, the geometry of a roof is the most important factors which affects

the level of comfort. Hence, details in designing roof into a suitable geometry is very

important. Although the geometry of roof in Kampung Villa, pitched roof, fulfilled the

principle of roof design, the overhang of the roof is too shallow in comparison to the

general roof design in tropical countries. Although this is one of the energy efficient

approach which allows sufficient natural light to enter the room, solar radiation might

transmit into the interior spaces easily through openings, for instance, windows and




doors especially during low solar angle. Not only by increasing heat gain, this design

might leads to the entrance of precipitation brought along by the wind.

Figure 4.0.1: The shallow roof overhang design in both Kampung Villa and Deluxe Suite.

5.0 Recommendation

As mentioned, the weakness of the existing roof design is that shallow overhang

which increase the heat gain of the building. In order to ensure the solar radiation could

be blocked from entering the interior spaces, the size of the roof overhang should be

extended deeper according to the solar angles so that the opening will be fully protected

from the sun and heat. But this approach will be blocking the entrance of natural

lighting and it might reduce the comfort of the spaces due to insufficient light source.

Therefore, the use of skylight is fully recommended for a building which is too enclosed

from the environment. Skylight can ensure the energy efficiency of a space because it

reduces the use of manmade lighting very effectively. In the other hand, skylight on

roof helps in promoting stack effects. Hot air in the room will raises up and provide

natural ventilation which will eventually reduce the average indoor temperature by air

exchange.

Besides, vertical shading device can also be added leaving the overhang untouched.

But this solution does not relates to the roof design. It is an additional recommendation

to achieve thermal comfort to the space.




6.0 Conclusion

The climate in tropical countries is always hot and the amount of rainfall is

comparatively higher. Hence, achieving thermal comfort is very important for a

building design in order to bear with the hot surrounding temperature and others thermal

condition. From observation and research, the roof designs in Phase 2 of Belum

Rainforest Resort has quite successfully achieve thermal comfort by being climatic

responsive and innovative in the other hand. For instance, the design in Deluxe Suite

seems does not fits the climate condition in the resort due to the use of concrete flat roof

which will be over exposed to the sun and the heavyweight of the material. But the

solutions taken to resolve problems mentioned has made the flat roof into such

comfortable functional space. In conclusion, the geometry, the materials and the design

elements of a roof are the most important factors which control the indoors thermal

condition and to ensure the achievement in thermal comfort. The roof design should be

further explore in order to provide a better living spaces for the occupants in the future.

This research paper will eventually contributes in a better roof design.




7.0 References

ASHRAE Standard 55, (2013). Thermal Environmental Conditions for Human

Occupancy. American National Standards Institute.

Gut, P. and Ackerknecht, D. (1993). Climate responsive building. St. Gallen,

Switzerland: SKAT.

Hyde, R. (2000). Climate responsive design. London: E & FN Spon.

John, L. M. (2000). Introduction to Landscape Design (2nd ed). New York, NY: John

Wily and Sons. Inc.

Koch-Nielsen, H. (2002). Stay cool. London, UK: James & James.

Paul, J. G. (1960). Form Function & Design. Ontario, CA: General Publishing

Company, Ltd.

Yannas, S., Erell, E. and Molina, J. (2006). Roof Cooling Techniques: The Design

Handbook. London, UK: Earthscan

Education

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