Although
still in the early stages there is expanding interest and momentum in the
Northwest to establish cross laminated timber, CLT, as an environmentally sound
building material that could also help revive struggling mills in the region.
Leading
the initiative in Washington state is Forterra, a non-profit group that works
to promote private and public partnerships in land conservation and sustainable
development.
Forterra
has brought together a coalition of government, timber industry and development
interests to push for strategies that will pave the way for greater adoption of
CLT as a building method.
Similar
work is underway in Oregon, where with state support a mill in Roseburg is
supplying CLT product for a new multi-story Portland mixed-use project, Albina
Yard, the first using domestic CLT certified for structural use in the country. http://www.albinayard.com/#the-yard
CLT
is formed out of milled wood in three to seven layers laid perpendicular, glued
and exposed to extreme high-pressure. The result is a materials that proponents
say is environmentally-sound, high-strength, fire resistant and energy
efficient.
The
resulting carbon footprint, recognizing the ability of wood to absorb carbon
even after harvest and manufacture, improves CLT’s environmental profile
compared with conventional materials such as concrete and steel, advocates say.
CLT
emerged as a viable construction material in Europe more than a decade ago, and
later migrated to Canada which has the largest manufacturing facility,
Structurlam, in North America. With the avid backing of architect Michael Green
the British Columbia government established a center in Prince George dedicated
to CLT technology.
One
of the largest projects in North America is Arbora, a Montreal mixed-use
development.
Thus
far, only the DR Johnson mill in Roseburg, Oregon is certified to manufacture
CLT for structural use in multi-story projects. However, a northwest Montana company,
SmartLam, has for a number of years been manufacturing CLT for industrial uses such
bridges, roads, oil field platforms and other applications.
SmartLam
has announced it is planning to obtain structural certification. A spokesman
noted that market demand could be especially strong for apartment and
multi-family construction.
A
significant obstacle to CLT adoption for multi-story structures are municipal
and other building codes that limit the height of wood buildings. Among
Forterra’s strategic objectives for 2017 is to work with the Internatinal Code
Council to create building codes favorable to CLT.
Also
on Forterra’s agenda is Washington legislation that would fund research and
technical assistance for CLT projects and to create design-build competitive demonstration
projects for public construction.
In
a preface to its recent report on CLT, Forterra noted the economic stresses on
the timber industry for the past two decades.
“Cross
laminated timber buildings decised and built in our cities with products milled
in our forest communities represents an opportunity to link the economic and
environmental health of urban and rural communites...”
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