Getting ready to insulate a new detatched 20x20 garage with a full loft. This may be heated in future. Has a hobby room. 2x4 walls. I am getting quotes on insulation but it looks like it's going to be significantly cheaper to install batts myself. From what I understand I should silicone or elastomeric caulk the sill to concrete pad. There are also small gaps between the osb walls. I should caulk these as well? What about the joints where 2x4 inside walls rest against osb? Where should I caulk and where expanding foam? Any advice appreciated.
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Caulk, expanding foam insulation
- Thread starter ilaudio
- Start date
Elginz
Well-known member
Caulk each bay (where the bat of insulation fits) all the way around and any holes from wiring or what ever may be, So each bay is sealed off. If there are electrical boxes, caulk all the holes in them, probably foam behind them (not a lot of room to place the insulation). The walls are easy, ceiling, and ventilating a little more involved.
There should already be a sill seal between the sill and the concrete.
There should already be a sill seal between the sill and the concrete.
theoldwizard1
Well-known member
Is there a preference for silicone or elastomeric caulk?
"Pure" silicon caulk is for bathtubs/showers. You want a "siliconized" latec caulk lot of god one out there.
More expensive but better is have a 1" of foam sprayed on all seams and connections between studs and sheathing. Then install your batts or rollls.
If you plan to finish the interior walls you can use wet or dry blown cellulose which is a bit cheaper than fiberglass. This is still a DIY job but it is probably a 2 or 3 man job. The "wet" cellulose sticks to the back of sheathing as you blow it in. Second man, uses a special tool to scrape it flush. Third guy cleans up and recycles what come off. Wall board must be hung within a few days. Dry is blown in after the wall board is hung.