Should I add rigid foam to the exterior of my house to get more R-value? I have 2x4 walls with vapor barrier. I was thinking of adding 2"-4" of rigid foam to try and get a R-value of R20-R30 including the insulation already in the walls.
I am worried about trapping moisture in the walls.
Yes, it is a good idea to insulate the outside of your house to increase your R-value. SM blue is the best Ridgid foam to use. If you're concerned about moisture the best way to beef up your R value is to sprayfoam from the inside.
All-IN RENOVATIONS
Foam Board is a solution. Being that your home is framed with 2/4 the chances of the insulation in the walls being installed correctly is slim to none. Inspections on a Building Envelope didn't exist. Outside Stucco is a great look and provides a insulated exterior without creating a VapourBarrier. Just adding foam board to a exterior is not ensuring your home will be properly insulated. Attic venting are just some of the other areas to consider.
Good Luck!
Cheers,
BMUSCOTTY
I agree with jeff, 2" exterior with 2x4 interior sprayed foam for best results. If you do'nt want to demo interior 2" outside with new windows will beef up you R-value. Do air test prior and after completion for peace of mind.
Adding rigid insulation is going to increase the R value of the building. Keep in mind there are other issues if the EPS is not installed correctly.
Right now it is vinyl siding.
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