Thursday, October 18, 2012

The Establishment of 'Air House' Standard in Tropical Countries : Part 3


Malaysian Vernacular Architecture and Its Relationship to Climate

Malaysia’s Climate

Geographically, two separated land areas form Malaysia, which are Peninsula Malaysia in the west, and the northern part of Borneo comprising Sabah and Sarawak in the east. This country lies between latitude 10 to 70 North and longitude 1000 to 1200 East. It can be said that Malaysia is located in the equatorial doldrums, with the characters of uniform temperature, high humidity and copious rainfall all year round (Malaysian Meteorological Department, 2012).

As a tropical country, Malaysia experiences high temperatures, with an annual mean minimum temperature of 22 0C and an annual mean maximum temperature of 34 0C (Hanafi, 1994). Figure 11 shows the average monthly rainfall and temperature for Malaysia from 1990 to 2009. It suggests that the average temperature in a year ranges from 25.5 0C to 26.5 0C, while the average rainfall is between 100mm to 300mm (University of East Anglia, 2012).




Figure 12 shows the rainfall tabulation for Peninsula Malaysia in June and December 2011. In June the rainfall tabulation was uniformed throughout the Peninsula Malaysia, while in December the rainfall was concentrated along the east coast.

Figure 13 displays the rainfall tabulation for Malaysia in March 2011, which showed that the country received high rainfall all year long. This region has high humidity with the lowest 67%; the average is more than 80% (Abdul Hussain Al-Obaidi & Woods, 2006). The wind flow for Malaysia is light and variable. The location of this country, specifically Peninsula Malaysia, is surrounded by the seas; this gives the effect of sea and land breezes. In the afternoon, sea breezes of 5.14 to 7.71 m/s (10 to 15 knots) are common, reaching up to several tens of kilometres inland (Malaysian Meteorological Department, 2012).



Traditional Malay ‘Kampong’


The unplanned arrangement of Malay houses indirectly helps to reduce the risk of strong winds where settlements along coastal areas experience higher wind speed than inland regions (Hanafi, 1994). The characters of a Malay kampong are detached, and dispersed units with ample external spaces between them to allow fresh air circulation (Hanafi, 1994).

However, the patterns of a traditional Malay kampong, which have similarities to villages in Indonesia, can be described in two main types of spatial arrangement: linear and concentric (Tjahjono, 2003). Figure 14 shows the linear and concentric settlement patterns of a Malay ‘kampong’. For a linear pattern, houses face the economic resources and transportation links such as roads, rivers or beaches; in a concentric pattern, the serambi usually faces the public space located at the centre of the houses.



In Malay house compounds, crop-bearing trees such as coconut trees and high branched fruity trees are planted (Yuan, 1987: 92; Hanafi, 1994). These trees have various functions, such as to indicate individual boundaries, provide fruits, and shade the pedestrian walkways (Figure 15). The open space compounds of a traditional Malay kampong can encourage social interaction within neighbourhoods (Yuan, 1987: 93).

For religious reasons, most traditional Malay houses are oriented to face Mecca (east-west direction), which indirectly minimizes the area of exposed walls to direct solar radiation during the day (Yuan, 2011).



Raised Floor


The uniqueness of a Malay house is that it is built on stilts. This approach in many ways has several benefits from a thermal, functional and safety point of view. The raised floor, which is built higher than the ground, can catch winds of a higher velocity (Yuan, 1987: 71), and the use of timber planks for the floor, which have gaps between them, can bring the air to the inner space. Hanafi (1994) suggests that moist ground requires more sunlight to dry, and a raised floor is one of the solutions. The wet climate does not just make the ground damp but can also cause floods. Therefore, stilt heights vary between Malay houses located in the northern and southern regions (Table 4).

Several research findings about stilt heights in traditional Malay houses have proved those in the northern region have more height than those in the southern region (Figure 16). The underneath space allocated by the raised floor can provide shelter for the livestock, working space, and a clothes-drying area during rainy seasons.



Walls and Openings


A traditional Malay house allows ventilation by having many full-length windows and doors at body level (Yuan, 1987: 76). Hassan and Ramli (2010) conclude that the large number of windows and openings aided by ornamentation at the perimeter walls can contribute to the cross ventilation process (Figure 17). However, further analysis by the same authors (2010) reveals that large openings on Malay house walls create high air intakes outside to reduce the performance of the stack effect. Table 5 shows detailed results of the study, which suggest that most of the indoor and outdoor temperatures were higher than 28 0C. Furthermore, the humidity level in the house is mostly higher than 60%. Meanwhile, the wind speed in the Malay house ranges from 0.3 m/s to 3.4 m/s.



Double-Slope Roof


Roof space in a traditional Malay house is properly ventilated by the provision of ventilation joints and panels in the roof construction (Yuan, 1987: 75). Figure 18 shows the roof’s opening on both sides to allow air movement into the house (Hanafi, 1994). As one of the indigenous materials, the attap roof used in Malay houses has a low thermal capacity. This material does not retain heat and cools immediately.

Another climatic responsive design of a double-slope roof is its gable ends. Having various motive designs, this component also has ventilation panels which allow air to flow into the roof space and cool the house (Yuan, 1987:111). As shown in Figure 19 the gable ends with ventilation in traditional Malay houses have various designs and can reach up to about 5 to 9 metres high (Chen, et al., 2008).






From the two examples in Figure 20, the roof overhangs in the Andak Endah house range from 1000mm to 1500mm, and the Datuk Baginda Tan Mas Mohar house has overhangs ranging from 1400mm to 1600mm. Large overhangs and the low exposed vertical areas (windows and walls) in a traditional Malay house provide good protection against driving rain, good shading, and allow the windows to be left open most of the time for ventilation (Yuan, 1987). Meanwhile, the roof angle for both cases ranges from 300 to 600. The steep roof angle is used to quickly drain off any rain falling onto the roof surface before it seeps through the layers of thatching (Lee, 2003:251).




Summaries and Key Points

The random arrangement of houses in a Malay kampong with high coconut trees promotes air movement and shade to the entire kampong. Meanwhile, the elevated floors, full-length windows on the perimeter walls and openings on roof structures allow large air movement into the house. Thus, the cross ventilation process can be achieved and compared to the stack effect.

The front-to-back arrangement of a Malay house preserves the privacy levels of the occupants. The serambi is one of the most important spaces and serves as an interaction area within the neighbourhood. Meanwhile, the rumah ibu area can have a flexible number of rooms according to the family size and needs. Therefore, the house is always meeting the basic needs of the residents from time to time. Furthermore, the lightweight materials such as timber, bamboo and attap roofing have a great advantage in Malaysia’s climate. These materials perform better as they cool down rapidly and heat up quickly during the day, even when there is a slight difference in outside temperature (Saini, 1970).

As a tropical country, Malaysia receives a lot of sunshine and copious rainfall throughout the year. These factors lead to high solar radiation, glare and traces of rainwater to the exposed walls. Low thermal mass materials used in a Malay house can release heat from solar radiation readily, while large overhangs can reduce glare and traces of rainwater.

The full-length windows in a traditional Malay house are divided into three components, which are top, middle and bottom. The middle and bottom components are operable and can be shut separately, while the top component is carved open at all times for ventilation. This system can allow air in according to residents’ needs.

Researched and Written by Mohd Firrdhaus Mohd Sahabuddin; co-founder of 'Air House' and this article was a part of his dissertation which titled 'Traditional Values and Their Adaptation in Social Housing Design: Towards A New Typology and Establishment of ‘Air House’ Standard in Malaysia' for MSc. Advanced Sustainable Design in The University of Edinburgh. Copyright 2012.








3 comments:

  1. Hello,
    I am architecte and lecturer at the school of architecture in Reunion Island (a small french tropical island in the indian ocean).
    I am working on a thesis "influence of natural ventilaiton on the evolution of the tropical architecture". I find your work very intersting and i a looking for lans, facades and cross sections of tropical vernacular houses. have you got some, or do you know whre i could get some?
    Regards
    antoine perrau mail aperrau@aparchitectures.fr

    ReplyDelete
  2. Hi Antoine,

    Thanks for visiting my blog. Yup i got two case studies for Traditional Malay Houses. I can email it to you if you want. Can you confirm your email address again. Thank you.

    Regards,
    Firr

    ReplyDelete