Stick-framed Roxul SIP
From my previous posts many know that I’ll soon build a “pretty good” house using double stud walls insulated with mineral wool. I think I have finally “invented” a construction method that is “reasonable”. It starts with ripped plywood top and bottom plates that are the width of the total wall, inner layer (with sheathing on it’s exterior face), mid-wall insulation and outer wall. The plywood ( I don’t trust OSB for this) is the bottom and top plate, second top plates of 2x lumber will be added as sections are erected. The wall(s) will be built in sections, 8′ the plywood plate length is the obvious first choice but not a constraint. The process of building a section begins with framing the inner wall then it is sheathed openings are cut and rimmed with plywood “picture frames then the sheathed layer is detailed with tape and caulk etc. as the primary air barrier. That done, the inter-wall insulation is “positioned” then the outer wall framing, insulation and, if used exterior sheathing. At each section boundary doubled studs (one in each section) are used on at least the inner wall to make a fast easily sealed joint. The sections go up and are caulked and sealed as they are added just like it was using foam SIPs, the inspection questions are also no different. The walls I’m planning use the process described with 2x4s 24″ OC stud spacing, staggered studs, is that really 12″ OC? I’m treating both as ” load bearing” in terms of headers etc. With the staggered studs section boundaries will not be insulated, in the outer wall before erection and exterior sheathing must be delayed or better, not used (my choice).For headers I’m planning on a simplified and minimized version of insulated box header framed with 2×3 and 1/2″ plywood insulated with 2 1/2″ Roxul my longest header is 70 1/2″. In my case once erected the house-wrap goes on then An XPS drainage plane (Kingspan Greenguard DC14) layer then steel panels (Amrico EZwall) that support “thin brick’. BTW I have a very detailed 3 D model in “Sketchp” a lmost done but I keep making changes. What do you think?
GBA Detail Library
A collection of one thousand construction details organized by climate and house part