Canada Wood Today | The Canada Wood Group

COFI Expands Market Opportunities for 2×10 and 2×12 in Japanese P&B Construction

Shawn Lawlor

By Shawn Lawlor

Director, Canada Wood Japan

January 28, 2019

Following an extensive testing program, in 2013 COFI obtained a voluntary evaluation certificate from the Japan Housing and Wood Technology Centre (HOWTEC) which eliminated technical barriers in using Canadian 2×4, 2×6 and 2×8 SPF, Douglas Fir and Hem-Fir dimension lumber in Japanese post and beam horizontal structural applications. Based on this third party evaluation, we developed an Excel based structural calculations tool to facilitate specification of dimension lumber in Post & Beam design. Over this 5-year period, approximately 100 structural engineers, builders and architects have downloaded this design tool from the COFI Japan site for use their projects. In 2018 COFI was required to renew this HOWTEC evaluation certificate and over the past year we’ve worked to expand the scope of this certificate to include wider width dimension as part of our ongoing market access work. We had been fielding requests by users in colder, heavier snow load regions in Japan to include 2×10 and 2×12 sizes as part of the horizontal diaphragm specifications. As the designers in these colder regions need to specify thicker thermal insulation in roof structure, the rafters with greater depths are desired than those in the previous evaluation. By the end of 2018 our HOWTEC renewal work resulted in us obtaining the new certificate and revising our structural design manual to include 2×10 and 2×12. We released the updated Excel design tool in early January and we have already received several messages from the design tool users thanking us for the expanded scope. The attached photos show an example of how the design tool is being utilized. The structural engineer who sent us these photos was successful in designing a P&B building with 2×10 SPF dimension lumber as roof rafters.