Current design values for Douglas fir and Western Larch lumber were affirmed by the Western Wood Products Association in August after tests found the species to have higher bending (+5.5%), tensile (+5%), and stiffness (+8.1%) properties than when it was last tested in the 1980s.
Douglas fir is the second major wood species to have its design values reviewed, following the American Lumber Standard Committee’s (ALSC) mandated review of Southern Yellow Pine design values earlier this year.
The tests included 36 mills in the Douglas fir and Western Larch production region that together provided 360 No. 2 2x4s each for bending and testing. The results will be submitted to the ALSC for review and will be confirmed in October.