Technical Information

Return to Technical main page

Why CLT over Steel or Concrete

Article text used with permission from Informed Infrastucture magazine article Future Forward: Can Cross-Laminated Timber Replace Concrete and Steel? 


Lesser weight is a key benefit of CLT, and speed of build is another incentive. Unlike concrete, which is poured into place, CLT panels are custom milled to become part of a building system that’s lifted into place onsite. Considering it’s made of wood, fire resistance is a surprising area in which CLT outperforms steel and concrete in tests performed in Europe, where CLT has been in use for more than 25 years. Similar tests in the United States support these findings.

I have a really compelling photo that I use in presentations where there are two failed steel I-beams draped over a timber beam, where the timber survived the fire, and the steel I-beams deformed and failed,” notes Malmquist. “Have you ever tried to light a log with a Bic lighter? There’s just so much mass there. The fire event will burn into the wood to a certain extent, lose its oxygen source and self extinguish. That is the hallmark of the mass timber; it will self extinguish and still have the residual structural capabilities.

Casey Malmquist – CEO and president of SmartLam

Environmental Benefits

Wood is a carbon store, so in the net carbon equation, CLT isn’t carbon neutral, but close, as opposed to very high carbon emissions in concrete and steel. Malmquist notes that in the United States, construction materials and activities contribute more to carbon emissions than automobiles.

“Wood arguably is the only renewable building material; it can literally be harvested. And our adhesive is kitchen grade — you can eat it, which again goes to the environmental side and sustainability.”

Casey Malmquist – CEO and president of SmartLam

Most of the tree stock used to make CLT is 12-inch diameter or less, making it sustainably harvestable. According to Malmquist, the company’s production capability on the new plant is about 48 billion board feet annually, which is about 12,000 logging trucks. He notes that it takes the North American forest only five hours and 12 minutes to regenerate that amount of wood fiber.

Read the full report at Informed Infrastucture magazine.