Any known gotchas when using 100mm PIR rigid foam between (deeper) attic floor joists? I plan to top up with 100mm Rockwool roll and not use the space for storage of any sort. Is it required to seal any gaps with tape?
R. Cott 14
Jun 11, 2017
3 Replies
Its very advisable
If going in from above use caulk or expanding foam.
Half the point of taping is moisture barrier. I guess that's not going to happen tho in this case...
I stapled up a moisture barrier before fitting the plasterboard. Gaps will be narrow as I will use the band saw and the joists appear to be parallel.
My experience of using a foam gun is that I am not very good at controlling the quantity of foam:-(
Biggest concern is *will BC want it done*.
I'd recommend getting an applicator gun - they dispense as much or as little as you need and the foam stays usable for months. Just be sure to close the valve after use and give it a good squirt through with cleaner when you change gun grade cannisters.
I could never get the hang of the disposable sort.
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