Renewable tropical architecture

19 September 2019 | Research - Impact

One of the world’s first tropical mass engineered timber façades has been pioneered by the NUS School of Design and Environment (SDE). The façade is mounted on the SDE test-bedding frame to examine dehydration behaviours of the permeable (right) and impermeable (left) configurations

An NUS School of Design and Environment (SDE) team has pioneered one of the world’s first tropical mass engineered timber (MET) façades. This paves the way for Singapore to be at the forefront of contemporary timber architecture for sustainability and wellbeing.

The innovative test-bedding façade at SDE4 was developed at the Sky Timber: Mass Timber Architecture in the Tropics, NUS-BFH International Workshop 2019. The workshop was led by Associate Professor Shinya Okuda and Research Associate Laurent Corpataux from NUS Architecture, as well as Professor Christophe Sigrist from the Bern University of Applied Sciences (BFH). From this, the façade prototypes were jointly developed and fabricated by a team of 11 NUS MArch students and 6 BFH students.

In regards to the newly developed MET façade, Professor Lam Khee Poh, Dean of the SDE, commented, “MET is one of the areas that could represent our school’s commitment toward sustainability and human wellbeing. We trust our ground-breaking test-bedding façade at SDE4 could support and promote such multi-disciplinary innovation across design, performance, science and engineering.”

Timber architecture has over a thousand years of history, and is well-researched as a renewable, sustainable building material. It has been shown to bring wellness benefits for people in the space by improving air quality, reducing CO2, blood pressure and stress, and can even increase cognitive ability. 

Timber was largely replaced by steel and concrete architecture in the 19th and 20th centuries, but today, increased awareness of climate change, as well as the scarcity and the rising cost of sand, is leading architects to revisit the use of timber as a building material.

Assoc Prof Okuda said, “In the 21st century, we must utilise alternative renewable resources, such as timber. In the tropics, due to year-round sunlight, some plantation species may grow roughly four times faster than those in a temperate climate. Our research focuses on fast-growing plantation species which may have relatively weak mechanical properties on their own, but may become suitable for construction use if developed into MET components.”

In general, MET has five times the strength/weight ratio compared to concrete, which may accelerate construction time up to 35% according to Building and Construction Authority Singapore. 

However, there are still many technical challenges in a tropical country like Singapore, due to high and constant humidity and temperature, as well as threats from termites. But the NUS SkyTimber™ team are discovering ways to resolve these great challenges at the Tropical Technology Lab, as well as SDE4 test-bedding facade. 

Assoc Prof Okuda, who is also appointed as Principal Investigator of the Innovative Mass Timber Construction Systems for High-density Urban Environment in the Tropics project, funded by Ministry of National Development and Building and Construction Authority Singapore, commented that, “One of the key factors for successful implementation of MET in the Tropics is keeping the timber moisture content lower than 20% to avoid fungus attacks and mechanical property deterioration. To keep the timber dry, we experimented with special tectonic designs to dehydrate and allow the timber to ‘breathe’, while preventing the rain from penetrating the outside.”

Timber facade interior_960.jpg

Interior detail of one the permeable tropical MET façade prototypes. There are intentional gaps between the MET elements to promote dehydration as breathing architecture

The innovative tectonic design increases the surface area for direct solar exposure and enhances airflow to speed up the dehydration, which allows the reduction of moisture content significantly. The aim of the prototypes is to test both permeable and impermeable options. “Concurrent testing at the Tropical Technology Lab is set up with the latest sensor technology to provide real-time data, with data analytics on the relationships between orientations/surface temperature/relative humidity and moisture content,” Assoc Prof Okuda added. 

With the highly prefabricated approach, there are enormous opportunities for Singapore to lead the MET design and construction in the region. Assoc Prof Okuda explained, “We believe that the NUS SkyTimber™ project could contribute to the sustainable built environment as well as renewable tropical forestry in the 21st Century.” 

The SkyTimber™ façade is mounted on the SDE4 test-bedding frame and directly visible from Clementi Road until the end of November 2019. This feature has been adapted from the NUS School of Design & Environment News.