Cross-laminated timber, or CLT, is touted as a more sustainable option for building construction than concrete and steel. But is it really? The answer is complicated.
CLT is intended to replace concrete and steel whose production accounts for about 13% of global carbon dioxide emissions. Wood in CLT panels pulled CO2 from the atmosphere, and that carbon should remain locked up as long as the building stands.
Some forest scientists, climate modelers, and materials experts question how much of an environmental net gain results from using CLT to replace concrete and steel. Part of the concern relates to choices the lumber industry makes in forestry practices and manufacturing.
Lots of carbon gets dumped into the atmosphere when logs are transformed into CLT, they say. Sawmills and CLT plants typically burn bark, sawdust, and other wood wastes for heat, releasing carbon. Piles of branches, treetops, and smaller trees left behind after a harvest are often burned or left to decompose—releasing carbon into the atmosphere.
When it comes to combating global climate change, the mantra of “wood is good” may be simplistic.
Related Stories
Codes and Standards | Jun 10, 2021
New York City cracks down on construction site safety
Buildings Dept. issues new safety legislation for City Council consideration.
Codes and Standards | Jun 9, 2021
ASHRAE updates health care facility ventilation standard
Includes improved guidance on thermal comfort, revisions to air filtration requirements.
Codes and Standards | Jun 8, 2021
American Wood Council releases new fire design specification
For design of wood members, assemblies, and connections to meet code requirements.
Codes and Standards | Jun 7, 2021
Guide provides strategies to overcome barriers to sustainable affordable housing
International Living Future Institute document helps with social, regulatory, and financial hurdles.
Codes and Standards | Jun 3, 2021
Conversion of large office buildings to residential will require revamped regulations
Post-1960 offices present ventilation, daylighting, and other challenges.
Codes and Standards | Jun 2, 2021
Dept. of Energy releases EnergyPlus and OpenStudio updates
New features include Python Plugin features and additional tabular reporting options.
Codes and Standards | Jun 1, 2021
Federal plan to double Canadian lumber tariffs draws intense criticism
Builders advised to stock up to deal with shortages.
Codes and Standards | Jun 1, 2021
Passive House standards proving their worth in multifamily sector
Energy performance beats conventionally built by 32% to 58%.
Codes and Standards | May 27, 2021
Pittsburgh combats construction fraud
Crackdown on tax, insurance, and workers’ comp malfeasance.
Codes and Standards | May 26, 2021
Proposal to add photovoltaic panels to the R2 Standard for electronics recycling
Hundreds of facilities in 33 countries could begin recycling PVs.
