Any issues with using rigid foam board as in fill in exterior walls.
200+ year old colonial I am residing from the exterior. Removing everything so I am looking at the back of the horse hair plaster. Could dense pak cellulose or have open or closed cell foam sprayed in from the exterior. The problem is timing. I will be working on this a couple days at a time stripping and sheathing. I have three sides to do and I don’t want to coordinate with an installer four or five times to come out when I am ready. So my thought was to use rigid foam (its post and beam) cut roughly to size and spray foam around the edges to seal it in place. Then fill the bay this way. I was even thinking the first sheet being polyiso with foil may work fairly good because it would be up against the keys of the plaster creating a small air space for the radiant barrier to work. Like I said this is not ideal but for my situation I thought it might be a good alternative. Please punch holes in my thinking! Thanks
By the way I am installing new plywood sheathing, typar, rainscreen, and vertical grain claps. Still debating on exterior rigid foam because of detail problems it may cause at the roof on the gable ends.
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I would use EPS or XPS boards and spray around. I can be installed quite easily and performs really well (I have done it in basement and upper floors)
I wouldn't use foil faced because it blocks vapor completely, which is generally not recommended.
To us spray foam is out of the question, as it's too risky and may cause long-term problems in the future, such as offgasing.
XPS is generally cheaper, too, and you don't have to risk your health. Plus foam boards will definitely give you an even insulation value, which may not always be the case in other types of insulations
Location, climate needed.
One note I am adding often. Whatever you do, the payback is not in this lifetime unless you buy your home at a discount for needing renovation in the first place.