Evaluation of Lumber from Deconstructed Portland Residential Buildings

Abstract

Portland, Oregon was the first U.S. city to implement a deconstruction ordinance in 2016. Although salvaged lumber from deconstructed dwellings can have high demand, the market for small-sized lumber is near saturation. New applications for this material are required for market development, industry diversification and the possible expansion of the deconstruction ordinance. Its use in mass timber is an option, but presently no wood property information exists for lumber from deconstructed dwellings inhibiting its use for structural purposes. Density and dynamic MOE (E) of 265, 38 mm x 89 mm (2 x 4) pieces of salvaged Douglas fir (Pseudotsuga menziesii) lumber were determined using a Metriguard Model 340 E-Computer. Additional data collected included sample dimensions, weight, and visual appearance. Over 50% of samples had a calculated stiffness comparable to the highest structural design grade for Coastal Douglas fir lumber. The presence of knots and damage, present in 66% and 59% of boards respectively, would likely downgrade boards, despite acceptable stiffness. Results show that 96% of samples were sufficiently stiff to meet minimum requirements for the manufacture of E3 grade cross laminated timber (CLT) panels and considering defects, this material is suitable for manufacturing CLT. Provision of wood property information for salvaged lumber is critical for market expansion and this work represents the first characterization of lumber from deconstructed Portland, OR dwellings.