Help with stucco house
I have a house that is stucco inside and out and altho cool in summer it is very cold in winter and almost impossible to heat. It is impossible to redo interior walls at this point so I am looking for a way to insulate to any degree on the outside. I have already installed all new windows so I guess that adds to the problem of insulation. I read some articles discussing this on your site. Please give me any suggestions you can. I am just a homeowner and have no construction background but I have someone to help me who has the general construction background. I had a friend who said she was an architect and she said the house did not need insulation due to the thickness of the walls ( it is stucco over cement block) but I now realize she did not know what she was talking about. There was some type of gray sand looking stuff put in the blocks that sifts out if you make a hole for any reason – perhaps that was insulation at some point???but provides no help now. Thanks for any help. House is in Northeast Alabama
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Replies
Block wall is somewhere around R3, so it would definitely be a challenge to heat even in the milder winters down south. The good news is that even a small amount of insulation will make a big difference.
If you don't want to touch the inside, the best would be adding an inch or two of exterior rigid foam and re-siding over it. Another option is EIFS, it provides insulation and exterior finish in one. With EIFS it is usually a small up-charge for extra insulation, going with 1.5" would bump your wall up to around R9, which would reduce your heat loss by 2/3.
If we assume the walls are 8 inch light blocks filled with Perlight insulation makes the current wall R6.95
https://www.perlite.org/wp-content/uploads/2018/03/perlite-loosefill-insulation.pdf
There is no easy way to improve the walls you would need to add to the inside or the outside and that get expensive fast making for a long payback.
I think you need an energy audit with IR photos taken on the coldest day possible.
Air sealing with a blower door test before and after is likely to make the house more comfortable.
Walt