At what scenario, in walls, is R21 high density fiberglass insulation used over R19?
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R21 Insulation
Builders Inc.
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At what scenario, in walls, is R21 high density fiberglass insulation used over R19?
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I would use the R-21 regardless.
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Well here’s the scenario. We work off of a consultant xactimate scope, bid it sight unseen and what was there was R19 and the consultant wrote R21. I bought R19. R19 is 6.25”. The walls are metal stud 2x8 on first floor and 2x6 from there up. The R21 insulation is spec’d for light gauge metal studs 5.5” the consultant wrote it wrong from being like kind material. We now have to do a deductive change order since the consultant spec’d the wrong pre existing material. From a municipal stand point for cost effectiveness and why would an architect would spec using R21 when there wouldn’t be a need for the “high density” feature of R21. From a comfort aspect I seriously doubt you could feel a difference in R21 vs R19 in a finished space other than your wallet or budget. I screwed up ordering R19 and just glanced at the 6” line item in the scope but the estimator screwed up in adding R21 to the scope instead of looking and seeing it actually had R19.... either way the customer is ok with us using R19=what is there previously.
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With metal studs bridging the space between your sheathing and Dry wall your wall averages about R8.6 with 24 C to C studs and R19 glass,,, R9.0 with R21 glass
Install a layer of 0.5" ANYTHING on the outside and you are a Genius.... And no silly tear outs.
Install a layer of 0.5" ANYTHING on the outside and you are a Genius.... And no silly tear outs.
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If you using high-density insulation... R-21 id for a 2x6 wall.
If you want to achieve R-21 in a 2x4 wall you have to use Polyurethane Rigid foam insulation which comes anywhere from R-18 to R-28 and it's 3 1/2" thick or use spray foam insulation.
If you want to achieve R-21 in a 2x4 wall you have to use Polyurethane Rigid foam insulation which comes anywhere from R-18 to R-28 and it's 3 1/2" thick or use spray foam insulation.
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Greg24K: You can't achieve R-24 with a 2 x 4 steel stud framed wall with the "steel" short circuiting the heat flow between the dry wall / exterior product.
Two inches of foam mounted across the studs on the exterior, and some fiber glass for sound control?
R-15 fiber glassed metal studs = ~7.8 R value for the whole panel....24" spacing, 6.4 R value for 16" C to C studing.
Two inches of foam mounted across the studs on the exterior, and some fiber glass for sound control?
R-15 fiber glassed metal studs = ~7.8 R value for the whole panel....24" spacing, 6.4 R value for 16" C to C studing.
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I was referring to wood studs before he made a follow-up post (I just saw it) where he mentioned metal studs.
I never use metal studs and the only time I used them is when I was doing a commercial job (25 years ago) and we didn't use insulation (it was between 2 stores) so I'm not really familiar with insulation methods when it comes to metal framing.
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