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creeky · 11-18-14, 05:26 PM

I would just point out. The pink stuff is xps insulation. According to recent testing it actually improves in R value as it gets cold. Polyiso. Which has the highest R value (6.5/"). Does not perform as well (r value decreases) in very cold temperatures. Something to watch for.

I like xps on the outside layer and polyiso as you move towards the warm part of the home. This gives you the best of both worlds. So for your 4" go 2 (r10) xps and 2 polyiso (r13). Now you have r23.

To save money you could try calling roofing/construction contractors. They often sell off end of job overs, demolition remains and culled insulation. Prices can be good.

I think it's only xps in contact with the ground. tho, little late for installing ground contact insulation this year.

11-18-14, 05:26 PM	#19
creeky Journeyman EcoRenovator Join Date: Jun 2011 Location: a field somewhere Posts: 304 Thanks: 64 Thanked 44 Times in 31 Posts	I would just point out. The pink stuff is xps insulation. According to recent testing it actually improves in R value as it gets cold. Polyiso. Which has the highest R value (6.5/"). Does not perform as well (r value decreases) in very cold temperatures. Something to watch for. I like xps on the outside layer and polyiso as you move towards the warm part of the home. This gives you the best of both worlds. So for your 4" go 2 (r10) xps and 2 polyiso (r13). Now you have r23. To save money you could try calling roofing/construction contractors. They often sell off end of job overs, demolition remains and culled insulation. Prices can be good. I think it's only xps in contact with the ground. tho, little late for installing ground contact insulation this year.