Injected foam insulation.

[RickSab]

I was at the Historic Bungalow Show in Chicago last weekend and one of the insulation venders was showing how they inject their foam insulation between the two wythes. They claim there is no problem filling the space. What do you guts think? I'd be afraid of trapping water.

[Tom Raymond]

I have very mixed feelings about retrofit applications for foam insulation. I think if the application is part of a more comprehensive renovation (ie an interior gut job, or a complete exterior cladding replacement) there will be far less opportunity for disastrous outcomes. I have opened up several houses with urea formaldehyde foam insulation that had sever rot issues, in fact it is the only thing I've seen that will cause Homasote sheathing to rot.

For my own home I seriously considered foaming the roof deck from the interior. The pros are considerable; the rigidity it would add to the structure, the thermal cushion of a partially conditioned attic, and energy conservation. The cons were pretty much just the costs, in order for me to be confident that I wasn't creating a potential moisture issue I would have to insulate after I replaced the roof cover and corrected the flashing errors that are present but not currently a problem. Considering that my roof is very close to the end of it's service life, it would also be a bit foolish to tear off a roof over a fresh foam job. Fiberglass insulation and a radiant barrier are far less costly and can be installed without concern about the roof deck and covering.

Ultimately I think there needs to be alot more study before I'd be comfortable injecting foam into the unseen cavities of an old house. Let me know how yours is fairing in say ten years [:-angel]

Tom

[kurt]

From what I've seen of the space(s) between wythes of brick, I have to wonder how the insulation would even work.

Maybe moisture, but I can imagine the material being so uneven in thickness and distribution that it doesn't work.