So, with the windows finally due any time now, my thoughts have returned to the wall insulation. Once the windows and door is done, I can finish the room. Since the windows take up a large part of the wall space, there's not a lot of stud space to fill, and I have 2 of the walls filled with batts. Probably less than a single roll. Been thinking about pulling that out (I can use it elsewhere) and putting in foamboard cut slightly undersized and then using great stuff around the perimeter of each panel. Wondering if this would cause any problems down the road. Any advice welcome.
Why are you looking to pull the batts? Foam board is usually an r4-r5 per inch. The batts muat be at least r13 which means 3" or so of foam to be equal. In my semi-professional opinion I'd stick with the fiberglass batts. The foam board sounds expensive, time consuming, and messy. Using great stuff to fill the gaps sounds f-bomb inducing as well.
2x4 stud walls, and the batts are r-15. Room is only 10x15'. f-bomb? The foam board is easier to cut than fiberglass batts. My thought was this would seal the wall better. For the amount I'll need, the expense shouldn't be too bad. I've got 2 walls that are 8x5', with a 4x5' window in each. Another wall @ 8x10' with an exterior 30" door, and a 4x5' window, and the last wall is 8x10 with 2 4x5' windows. There isn't a single full width stud space anywhere. It's something I'm considering....but I'm not at the point where it's going to get done just yet.
Trust me, it is easier to cut the bats than to cut the foam board (actually, easier to size since bat insulation is pliable = forgiving). Not saying don't do foam board (I have put up plenty in my house), but don't use that reasoning to make your decision. It may be possible for you to use both - I did that along a 12' section of my foundation; Built the frame, glued rigid foam to the foundation, attached 2x 3 studs to the frame, put in R13 bats, then drywall. Also did something similar a few places on the main floor that didn't have room for full thickness of R13 bats; cut foam to size and glued it in, then stripped layers off a bat to fill in the rest of the way. However, most of my upstairs is done with custom cut bats because none of the house has evenly spaced studs - it's really pretty easy once you get into a rhythm. Plus, any cuttings can be combined to fill in small places around doors and windows. Whatever way you decide on, good luck!
Enough to fill the 3.5" cavities. Thickest I saw at HD was 2", so I'd have to do a combo. Yeah, batts aren't terrible (I've done a lot). Anything will be better than what was in the walls. Maybe I could do 1/2" board, then fill with R-15 batts. They'd be slightly compressed. Modified flash 'n batt.
Just remember big Papa, anytime you compress insulation, you reduce its R value. It's supposed to be full of air, not partially full... I know you know that already, I was jus sayin....
Since batts aren't really very good at stopping air, the thought was the boards would help with that. I've caulked the heck outta these walls, but the place is like a sieve. Don't know if you saw the pics I put up when I first tore into the walls, but I found a spot where the exterior sheathing (1x10s I think) was about 1/2" away from the studs at the base of one wall. I just stared at that for several minutes shaking my head. Sloppy doesn't describe how this house was built, but it's close. Massive air leak, It got foamed. I'm tellin' ya', I'd love to tear the house down and rebuild, but it ain't happenin', so I do wut I can-can.......man.
Dave, have you looked at the homeowner grade spray-in foam kits? For that small amount of need, it might be worth investigating, if ya haven't yet.... Of course, using a spray foam set up like that over the cans at HD or lowes would mite cause you to utter the "f bomb" in place of simple nouns, adjectives, verbs, possibly adverbs, who knows
I've gutted a few rooms. I had rough pine horizontal with gaps for sheathing. I caulked the gaps and any other spaces. R 13 plastic vapor barrier. I even caulked where the plastic met electric boxes and window openings. It was pretty tight at the end.
Kinda what I've been doing in there Jon. Horizontal Pine boards with a very slight gap.....all caulked, yep. Eric, I have checked out those kits. Several hundred bucks to do this little room seemed a bit of overkill, but I have considered that too.
How about installing the new windows and see how tight it gets? It may be short gains redoing the walls...
You are right, the foam will stop air filtration a lot better than bats with a vapor barrier. If cost is a consideration, my vote would be for the combination. but if it isn't (or there isn't much difference), then I don't think you can go wrong by doubling up the foam board either. If your place was anything like mine, just getting something in there is a major improvement - and wind stoppage (either with vapor barrier or rigid foam) is the icing on the cake.
Oh yeah, you probably already know this, but make sure to get glue that is compatible with the rigid foam (if you go with that), the wrong stuff melts it.
I just used a utility knife and broke it like you would drywall. But if I had an electric knife, and thought about it, I think that would make it even easier.
I definitely don't recommend a table saw on long rips... 2" foam will stop a 15 amp motor like case hardened oak... Don't ask me how I know that
Yep, made an attic hatch cover last year and used PL 300 or whatever it was. Rated for the foam board This might be the goodest suggestion. I'm hoping I get a call sooner than later on the delivery, but I gotta have enough time to ply the conscripted help with goodies to avoid rebellion.
