For this 5-unit entry-level, zero-net-energy subdivision in Washington County, Oregon, the builder used an innovative “Thermal Break Shear” (TBS) wall assembly with rigid foam insulation between the lumber framing and plywood sheathing in an otherwise conventional light-frame wall assembly. The Code Official required proof the proposed shear wall assembly would be capable to resist code level seismic forces, so the builder contracted with Oregon State University to perform destructive seismic testing, which demonstrated not only that the assembly complies with structural code, but surprisingly, TBS wall is significantly more resilient in an earthquake than a conventional wall.
We reduced air leakage and thermal bridges by replacing our through-roof plumbing waste piping vent system with a combination of air admittance valves (AAV) and a two-way, filtered outdoor valve. Oregon’s plumbing code recognized AAVs, but restricted their use to 3 per house and required one through-roof vent. On appeal, the City of Portland allowed us to install AAVs according to manufacturer’s guidelines so we could eliminate all through-roof vents, using the “alternate materials and methods” provision through its Alternative Technology Advisory Committee (ATAC) process.
American Assets Trust developed this mixed-use three-building project that spans four blocks as part of Portland’s Lloyd EcoDistrict. The three buildings share one of the largest natural organic recycling treatment systems in the US, which treats all the buildings’ wastewater (including human waste from toilets) for reuse for toilet flushing, mechanical cooling and below surface landscape irrigation in an urban setting. It was permitted as a Water Pollution Control Facility with two on-site injection dry wells. The project showcases the economic and ecological benefits of district scale onsite wastewater treatment and reuse.