Image Credit: Vision Home Inspections
Last week we conducted a blower door test on the largest home to date; 8500ft2, with over 90,000 cubic feet of air volume. I was concerned that the fan wouldn’t have the power to get a complete reading, so imagine my surprise to see readings ticking in almost immediately! With 5 air changes per hour (-50pa) being the maximum allowed, this home was just above 2. This was especially strange given that the HVAC ducts were located in the attic and crawlspace, which always increases air leakage to the outside. I triple and quadruple checked my calculations, and then I remembered the contractor telling me how they had used Zip Panels on the exterior and seam-sealed the wall plate and stud connections using closed cell foam strips. This seems to be a very impressive system and will hopefully aid contractors in achieving the new <4ACH requirement in the new 2021 WA Energy Code.
From the manufacturer:
“ZIP System® sheathing and tape is a unique structural roof and wall
system with a built-in water-resistive barrier (WRB) and continuous air
barrier to keep out water and air, while allowing panels to properly dry.
By replacing the need for housewrap, it streamlines the weatherization
process – simply hang panels and applying panel seam tape in one trip
around the structure.”
Image Credit: ZIP System® Wall Sheathing | Huber Engineered Woods (huberwood.com)