“The Smile” in London made from CLT

A building made of wood may sound like nothing new, but still “The Smile” in London is the first of its kind. Made in a collaboration between Alison Brooks Architects, engineering firm Arup and the American Hardwood Export Council, “The Smile” is the first project in the world made from large hardwood CLT panels, erected for the London Design Festival 2016.

CLT, which stands for Cross Laminated Timber, is a relatively new development in wood construction, but it is already proclaimed as the material that will define our era. Normal wood is strong in the direction of the fibres, but weak in the cross direction, but CLT solves that problem. The panels are made from stacking small planks of wood in an odd amount of layers (usually three to seven), which are placed in a right angle at each successive layer, creating a ‘sandwich’ construction. The planks are bonded with structural adhesives and pressed to form a solid, straight, rectangular panel.

CLT is lightweight, much lighter than a slab of concrete of the same size, yet very strong, with great acoustic, fire, seismic, and thermal performance. Machined to tight tolerances, it is installed as easily as an IKEA bookcase.

Most CLT is made from softwoods, usually spruce, but three years ago, the American Hardwood Export Council started to experiment with hardwoods, specifically tulipwood. This is the type of material The Smile was made from as well. In 2014, another construction was erected from this type of CLT for the London Design Festival, but “The Smile” is the first to use large panels of the material for a building and the most complex structure ever made of CLT.

“The Smile”
The construction is a 3.5 m high, 4.5 m wide and 34 m long (11.5 x 14.8 x 111.5 feet) rectangular curved tube, made from the largest CLT plats available, which are 4.5 x 20 m (14.8 x 65.6 feet). The structure is a huge arc, forming two cantilevers from a single point in the centre.

You enter the tube in the middle where you are guided to the balcony on either end by small holes in the wall during the day and light strips at night. The structure is designed to resist approximately 10 tonnes of wind loading. It is screwed to a large wooden box that is filled with 20 tonnes of steel weights to prevent if from tipping over.

The structure will be on show until 12 October 2016. Location: Chelsea College of Arts, 16 John Islip Street London SW1P 4JU