WISA-Spruce BT Plywood

WISA-Spruce BT is standard WISA spruce plywood with a wood protective treatment against staining and decaying fungi. It's designed for the phase of a build where a panel is going to sit in the weather for weeks or months before it gets a roof over it, paint on it, or cladding covering it. This is what we used for the roof and the exterior sheathing of our off-grid cabin. It's also become my go-to for serious shop projects. Outfeed tables, big assembly surfaces, anything that'll take a beating over years in a workshop that isn't climate controlled. Important caveat from WISA: BT is a construction-phase protection, not a permanent outdoor finish. Any BT panel that will stay visible outside the finished building needs a paint or coating. Don't leave it bare and exposed to rain and sun forever. It will weather.