Why tulipwood CLT?

AHEC has been closely following developments in the world of wood construction with much interest. We have seen the emergence of a series of practical and innovative uses of wood in building; glued laminated timber (glulam), laminated veneer lumber (LVL) and more recently, cross laminated timber (CLT). The latter has enabled wood construction to reach new heights, literally. 

It is designed to maximise yield, utilise lower grades of lumber, and it can be made potentially in a high volume of very large sections. The result is a light but very strong panel product that can be made off-site and erected quickly to form structural walls, floors and ceilings. 

For the first time in recent building history, wood has a real chance to compete with concrete, surpassing it with regards to the all-important environmental credentials. Wood’s renewability, low embodied energy, and potential as a carbon store during use, are all massive benefits. This is a great advantage for our industry as we move into an era where genuine sustainable building is soon to become one of the major drivers for construction. 

Understandably, to compete with concrete and provide the structural fabric of buildings, CLT needs to be competitively priced. So it makes perfect sense that, up until now, the focus has been on sources of cheap fibre, namely low-grade softwood such as sitka spruce. What the CLT industry has yet to recognise is that some hardwoods can be very competitively priced but at the same time offer up to twice the inherent strength, potentially presenting an opportunity to significantly reduce the amount of fibre (or mass) required to achieve the same strength performance. 

AHEC chose to experiment with CLT using American tulipwood; it is not an expensive hardwood, there is lots of it, its mechanical properties are excellent, and most importantly, it is incredibly strong for its weight. 

It was this concept that AHEC presented to dRMM Architects at the end of 2012, which has led to the first ever use of hardwood CLT pioneered in the Endless Stair, a striking sculpture that is currently on the lawn in front of Tate Modern. We believe this unique experimental project will change thinking and has added a new dimension to timber in construction.


Profile picture for user David Venables
David Venables


David Venables is the European Director for the [...]