Timeline for Should I install vapor barrier over XPS insulation panels?
Current License: CC BY-SA 4.0
5 events
| when toggle format | what | by | license | comment | |
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| Aug 3, 2020 at 4:22 | comment | added | P2000 | Ah, I see. As you perhaps know, the required R value is defined in your national code and climate zone, and may differentiate between above/below grade. You have 2xR10 plus a bit (I think R3) for the drywall and sheathing. Is that enough for your area? In any case I would fill it with fibre glass. Compress a thicker batt, e.g. a 3.5in down to 1.5in to get even more R than you would with 1.5in uncompressed ("peeled") fiber glass. You can also drop down to the cheaper EPS. | |
| Aug 3, 2020 at 2:49 | comment | added | Jake Schmitz | I have 5 1/2 inches of space between my sheathing and the finished wall. If I double up two 2" foam boards, that leaves me with about 1 1/2" of space to deal with. | |
| Aug 3, 2020 at 0:45 | comment | added | P2000 | The sheething breathes outward. I am not sure what you mean with "air gap between my two foam boards". Are you layering? I have not left a gap. I had it against concrete, and then filled the remaining space with fiber glass insulation batting. The fibre glass then breathes into the house, and this works if the XPS is thick enough for your climate to prevent condensation on its inside surface. | |
| Aug 2, 2020 at 21:28 | comment | added | Jake Schmitz | Should I worry about having the XPS foam board all the way against the exterior sheathing? I plan on leaving a small air gap between my two foam boards since that will also "help" insulate/buffer. But wondering if I should also leave some breathing space for the sheathing | |
| Jul 26, 2020 at 4:52 | history | answered | P2000 | CC BY-SA 4.0 |