CLT houses for green Lanka

If most good things begin in the home, so must the life-or-death battle relating to global warming. Across the world, creative and innovative architects have developed more affordable and eco-friendly ways of building houses. Sri Lanka’s Housing and Construction Minister Sajith Premadasa, continuing the good work his father started, has launched hundreds of projects, mainly in rural areas, to provide houses with deeds and small plots of land to homeless people. Social analysts see this as the first major step towards restoring the dignity of these poverty-stricken families, so that they could earn their living and rise from the second-class citizenship of living on the dole.

According to the New Statesman, wood is making a comeback in housing.

If the 17th century was the age of stone, the 18th was the peak of the brick building, the 20th was built on concrete, then the 21st century, according to expert Alex de Rijke, should mark “the time for timber.”

Mr. Alex de Rijke, the director of London-based architecture firm dRMM, which has been working with the material for more than a decade, believes that products such as cross-laminated timber (CLT) – a wood panel product made from gluing layers of solid-sawn lumber together- are on course to take over the building industry.

Timber, according to Mr. de Rijke, has significant advantages over steel, concrete or masonry construction in terms of its environmental credentials, speed, weight, and structure.

If the rising number of mass timber projects – taller building with CLT frames, sometimes called “plyscrapers” - is anything to go by, then it would appear that Mr. de Rijke is not alone in his thinking.

He credits a historical reconstruction project as one of the main reasons for wood making its comeback on the building scene. Shakespeare’s Globe in the London borough of Southwark was rebuilt in 1997. According to Mr. de Rijke, it forced architects, engineers and planners to reconsider applying timber framework and helped to instill confidence in its use safely and sustainably for complex public buildings and for future housing developments.

CLT, developed in Austria in the early 1990s, has since steadily achieved mass adoption throughout the international architecture trade. This is partly due to the green building drive and widespread aim to make houses or public spaces more energy-efficient. The material is produced off-site in a factory from sustainably sourced timber. It is also much lighter. This allows for reduced slabs. Furthermore, the accuracy with which CLT panels can be cut and routed and the inherent structural properties allow for a huge amount of flexibility, the New Statesman says.

Andrew Waugh, director of Waugh Thistleton Architects (WTA), is thrilled that wood is making its comeback and says that mass timber buildings weigh “as little as a one-fifth of concrete structures”. As a result, he adds, mass timber buildings are a potential solution for construction in dense urban situations. WTA recently completed work on Dalston Lane, a 121-unit CLT mid-rise block of flats located above a Eurostar tunnel in Hackney.

Built with timber engineering specialists Ramboll, Dalston Lane is a group of stepped towers, the tallest of which rises ten stories. CLT panels were used for the external, party and core walls of the building, as well as the stairs and the building’s floors.

The architects’ use of CLT resulted in a lighter building that allowed the designers to build further up without extensive foundations.

The final building, with its staggered tower sizes, Mr Waugh says, maximises exposure to daylight in each apartment. The added height allowed the architects to add 50 more units to the project than originally permitted. This, Mr Waugh notes, is “a testament to just how light CLT can be”.

The Minister and Sri Lanka’s housing authorities need to seriously consider CLT housing projects, especially in the multi-million dollar Megapolis and Western Province schemes. We could save money and time besides building eco-family houses and the foundation for a Green Lanka.