I have been a long time lurker and member of this forum for a few years now. My family was going to be building a small home on the family farm and we were on our way when God had other plans. My father-n-law who owns the farm we were going to be building on was diagnosed with stage 4 cancer. Since we were going to inherent the farm any way; he asked us to move into the old farm house with him and we could renovate the old farm house instead of building.
That was 1 year ago.....and I have since installed a whole HVAC system (heat pump, A/C unit, dual source furnace, and OWB), renovated the kitchen, and slowly doing the electrical. In the spring, I will be redoing the entire plumbing system ( PEX home-runs to a manabloc, and schedule 40 for the septic that is currently cast).
My current issue is the R-value in the exterior walls-----there is none and the walls are 2x4 studs 16 on center. NC does requires R-19 for exterior walls. Would using R-15 with a R-5 foam board work or will that combo be too thick and I should just go ahead and do the closed-cell spray foam? The house was built in 1959.
The nice thing about the spray foam is that it does all the air leakage sealing at the same time you get insulation value.
Batt insulation was made to be a convenient material to use that came with a certified R-value. Even the most careful installation of batts still needs an air barrier. The foam sheets applied externally over the sheathing/framing can do that air sealing too. I don't think you can have too much insulation.
If you are in a humid climate and especially if you have refrigerated A/C the foam panels on the outside also provide the vapor barrier where it should be; outside the walls, not inside. Spray foam in the stud bays is good for that too.
I installed spray foam in an old house that my wife and I are renovating. I can tell you, that if you can afford it, you will not be disappointed. The house is easily heated and cooled. We had the house torn down to the studs and rafters, which made it easy for the crew to insulate.
Thanks guys.... I thin that's what I will be doing.