Getting a good permanent seal – or any real seal – between a cement block wall and a wooden windowframe is probably a known art.
We just don’t happen to know it. And after several years of weather drying out caulk and shrinking wood…
Well, nobody’s looking for perfection but this may be taking imperfection to unnecessary extremes. So…
…Tobie and I expended our caulk stash getting a start on going all the way around Ian’s two big windows, inside and out, before the cracks get so big snakes can slither through.
My goodness those are large gaps… Ian’s place is what, ten years old? I would have thought that by now there wouldn’t be an issue with the wood contracting, just the caulk drying out. Yes I know that the desert is a whole other issue but still…
I’ve used spray sealant for similar problems. The latex stuff (DapTex is one brand, LocTite might be another) is flexible enough to handle expansion–I’m sealing plastic to aluminum framing. The dispenser straw can be cleaned for reuse if you get it before it cures.
Not sure if Great Stuff makes a flexible foam; the hard urethane foam sort of works to seal plastic to steel framing, but that’s for a greenhouse that already leaks. All of this is in the high country (4300′) in the arid part of Oregon. Not quite desert, but close.
Maybe get some foam backer rod to save on the caulk and keep something in the gaps?
+1 to WJW’s comment. You could also use some low expansion spray foam and then caulk both inside and out.
Probably should have been installed with foam weatherstripping jammed in the gap. After caulking, would nailed-on trim be an option?
Theres a specialized caulking that has lots of stretch that they use in log home construction.
Elastomeric sealant is the high stretch/high bond caulk for something like this. Just be sure to get a version that lists both wood and concrete on the label. There are lots of different types and not all are suitable for all surfaces.
@ winston smith – There are several brands of caulk designed for log homes. The problem is that they are all very expensive.
Joel would be better off filling the gapes with non expansion foam or insulation and then covering that with regular 3M silicone caulk.
I use Great Stuff , window / low expansion foam . Then put Dap concrete sealant on both sides
I’d probably call a 3 M rep. If they don’t know the answer, maybe they can point you in the right direction.
Mike, buy once cry once is the way i have found is best for most things. of course, its up to each individual and his situation to determine what is best for Him.
(i also like the idea of call an expert and asking him)
Sonolastic NP1, but here’s the most important part:
Use backer rod. Just pumping caulk, any caulk, into that gap will result in similar results down the road. Your depth to width ratio on a caulk joint should be 1 to 1 at most. If you can’t do 1 to 1, you should go wider than you go deep. It’s just the way caulking works, any caulk applied to be deeper than it is wide will fail in short order. I won’t go into detail here as to why, but you can Goolge it if you desire an explanation.