trimming out around rigid foam
If I can use 2″ Polyisocyanurate any ideas how to trim it out. I was going to build out around windows and doors with 2×3 but it seems that the best place to have insulation is around windows and doors. The biggest issue I think would be building out extension of window jambs?
Replies
I'll give you a no answer answer (a "bump") to keep your topic on the board, but don't really have a good answer.
My uniformed answer would be that you'll need trim around the windows and doors anyway and you'll need something to attach your siding to and something to seal between windows and siding, so 2x3's wouldn't be bad. Insulation is good, but so is structure.
From the wording of your post, it sounds like you are talking about putting foam on the outside of your house (although your other question talks about putting foam on the interior). For outside foam, I would recommend you cover the whole outside of the house with foam first, then apply furring strips over the foam. You can use solid lumber for your strips, or you can cut them out of plywood (and make them any width you want). Cut the foam flush with your rough openings, and use wider strips (6" inches or so) over the foam to allow for installation of doors and windows, trim, flashing and siding. Yes, this will add a bit of depth to your walls, but you're going to be doing jamb extentions already, so I wouldn't worry about the small increase in depth. As for attaching the furring strips to your house, different folks will tell you different things - I'd use the heaviest and longest screws you can find and make sure you anchor into solid framing as much as possible. Some people worry that strips might slip downward over time with the weight of heavy siding (as in hardie plank) hanging from it, but I don't think it's a big problem if you fasten the strips well. If you are concerned about it, you could always use a small lag bolt at the top of each furring strip and then fasten the rest of the strip with regular screws. If your question is actually about putting foam on the interior, you can pretty much do the same thing I've described above. The furring strips will allow you to fasten your sheetrock and give you backing to secure your trim.
Edited 6/17/2008 9:15 am ET by bk24
Edited 6/17/2008 9:21 am ET by bk24