Had a great Science Cafe discussion Wednesday about engineered lumber, a.k.a. mass timber a.k.a. cross-laminated timber, and its present and future role in construction.
Because I moderate these sessions, walking around with a microphone a la Phil Donohue, I can’t take notes for a story; you’ll have to wait for ConcordTV to put up their video of the discussion. But here are a few takeaways I remember:
- Cross-laminated timber, which is the real technological breakthrough in the field, is currently made only with spruce and fir because their strength, not hemlock or pine or hardwoods. New Hampshire has little spruce and fir south of the White Mountains, so even if the field catches on it won’t help loggers and timber owners in the southern part of the state.
- University of Maine is the regional leader in research and development for the field – which makes sense, since Maine has *lots* of spruce and fir. Its Advanced Structures and Composite Center was called the “big dog” in the field.
- For developers, a huge advantage of mass timber is that buildings can be built much more quickly, by a factor of 2 or more. This means they can get paying tenants sooner, which can make all the difference in a project’s success. This also means that building with mass timber rather than steel and concrete can actually be cheaper, even though individual components are more expensive.
- Many mass timber components are built in a factory and shipped to the site, often drilled and cut with CNC machines indoors, rather than assembled up on scaffolding by workers in the rain and cold and heat and wind. This means they can be more precisely constructed with better fit together, said panelists.
- The reason that New Hampshire is seeing its first CLT building, a three-story office building on the Pease Tradeport, isn’t because mass timber is cool or useful or good for fighting climate change – it’s because all that exposed wood can look great. The developer wanted to echo the steampunk-ish look of refurbished mill buildings. Aesthetics rules!
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Who is / was “Phil Donohue?”!
I understand that the lumber for the first cross laminated mass timber building in Newington at Pease and designed by U Maine ASCC “big dog” (Black Bears?) actually was sourced from the Pacific Northwest forests. The lumber did NOT come from northern New England spruce or fir forests on the NH building project. Not sure why but it adds that transportation cost to the carbon footprint.