Been watching the reruns of “This Old House- Weston timber frame”.
They are doing shop prefab of exterior walls.
2×4 frame
OSB sheathing both sides
foam injected thru holes in OSB until it comes out other bleed holes
2″ foam sheets on outside- carefully taped to prevent air infiltration (said to also stop thermal bridging
siding over the foam
2x fur out on inside for utility runs so they don’t broach the 2×4 structure & insulation
dry wall or paneling on inside.
OK, I have several questions/thoughts.
1) with all that work to seal the outside doesn’t the nailing of the siding undo that? And does the siding hang tight?
2) anybody tried that injection method retro of old uninsinuated houses?
3) thoughts on using that sealed stud space/fur-out for utilities in stick-frame work?
Just thinking!
Edited 5/9/2009 2:31 pm ET by jimcco
Edited 5/9/2009 2:34 pm ET by jimcco
Replies
Bump.
>>2x fur out on inside for utility runs so they don't broach the 2x4 structure & insulation<<
How did they attach the 2x furring to the inside? Glue?
I assume the 2" foam was glued to the outside?
>>> Siding.....? <<< siding could hang tight if the outside was also furred......
Starting to get some pretty thick walls here - extension jambs and all that good stuff in their future..
Jim
Inside was just nailed.
Outside foam was nailed & taped. It was the outside sheet foam they were trying to make air tight so no fur; but how did they then nail sideing.
>>but how did they then nail sideing.<<
My guess is 3" nails - no firring = lots of holes in the outside layer of OSB, could have lots less holes through the OSB if they did fir it out.
Firring would require some holes though the OSB, but less than nailing the siding directly.
The siding nails would penetrate the firring and some of the foam layer, but not the OSB.
Jim
Never underestimate the value of a sharp pencil or good light.