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blown in plus rigid foam board or furring out?


OutofTown's Avatar
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Join Date: May 2005
Posts: 32
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11-06-10, 04:51 PM   #1  
blown in plus rigid foam board or furring out?

i have the option (at the same cost) to blow in 3 1/2" then add rigid foam over the sheathing OR pull off the sheathing and furring the studs out to % 1/2 or 6" the R values will be almost exactly the same R19.

I imagine if we take the sheathing off and deepen the cavity that we would house wrap after the sheathing goes back on. whereas if we use blown and rigid insulation we would just tape the seams between the panels and siding nails would then pierce the rigid foam when installed.

ideas?

 
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GBR in WA's Avatar
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Join Date: Mar 2009
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11-12-10, 09:12 PM   #2  
The studs will be the thermal losers. The structural sheathing is required on the corners and every ? feet as per code. One story or two, seismic zone or high wind? Remove and replace the windows, doors? Add furring, type of siding on the foam board? Location?

Gary

 
OutofTown's Avatar
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Join Date: May 2005
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11-17-10, 10:47 PM   #3  
thanks for the response,

Its a one story ranch. No special conditions in my area, excepting here in Oregon very wet 6 months of the year. Keeping the windows and doors. I will add to the sills and side trim of the existing windows, the trim over the top meets the soffit so we are just boxing that in with the new side trim piece. Planned to use 1/2 x 3" for furring and screw it over the studs vertically 16" on center with some kind of bug guard filling the gaps at the bottom. Didnt want to plug the rigid insulation full of holes so the hardboard (not cement) siding only gets nailed to the furring (should stay up with good siding nails eh?)

thoughts?

 
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