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 | Feb 27, 2017
Green building saves operating costs and boosts asset value
A new report shows 14% cost savings and a 7% increase in value when green standards are met.
Codes and Standards | Feb 24, 2017
Scant data hampering energy, water efficiency at sports venues
New NIBS report says baseline information needs further development.
Codes and Standards | Feb 22, 2017
Plans for WELL Building Standard include linkage with other green building standards
The planned updated version will be customizable for any building type.
Codes and Standards | Feb 21, 2017
Aging building code inspectors and government belt-tightening could cause crisis
Inspectors are edging toward retirement with no understudies in place.
Codes and Standards | Feb 20, 2017
AISI publishes three new cold-formed steel framing research reports
Seismic simulation, roof trusses, steel-to-steel and sheathing-to-steel connections are examined in the reports.
Codes and Standards | Feb 17, 2017
New energy design guide for metal building systems now available
The second edition incorporates more recent IECC and ASHRAE standards.
Codes and Standards | Feb 14, 2017
Paper outlines how BREEAM credits can be used for WELL standard compliance
The paper provides guidance on how to streamline pursuit of dual certification.
Codes and Standards | Feb 14, 2017
Evidence mounts on health, productivity benefits of sustainable work spaces
High-performance green buildings are linked to better job performance.
Codes and Standards | Feb 13, 2017
Calif. commission approves ‘emergency’ balcony code changes
The changes apply to multifamily, hotels, state-owned buildings, and public schools.
Codes and Standards | Feb 9, 2017
Google-initiated program aims to get construction industry to use healthier building materials
Portico platform features a database of products ranked on how they disclose ingredients.
