Comments on: Flat or Lumpy – How Would You Like Your Insulation?

By: Allison Bailes

Allison Bailes — Sat, 31 Mar 2012 18:09:42 +0000

Andy P:
Andy P: You got it.

By: Andy P

Andy P — Sat, 31 Mar 2012 06:25:32 +0000

So I suppose the same
So I suppose the same principle would apply to some insulated concrete forms, where a proportion of the insulation is full width (e.g. 8 inches) and a proportion is only an inch or two either side of a concrete column? And to whole wall R-value calculations for wood framed walls? But even more complicated when you introduce non-linear thermal bridging e.g. steel studs.

By: Allison Bailes

Allison Bailes — Fri, 07 Jan 2011 20:42:05 +0000

Chris, as a matter of fact, I
Chris, as a matter of fact, I wrote this article because of the very issue you raise. I wanted to write an article about problems with spray foam, one of them being uneven distribution of the foam, but then I realized I needed an article before that explaining why uneven distribution was so bad. So, I wrote this article on 6/28 and the spray foam article on 6/29. In fact, the video in that spray foam article has exactly the kind of installation you described. It's almost like you know where I filmed that video.

By: Chris

Chris — Fri, 07 Jan 2011 19:53:00 +0000

Our animal friends may not
Our animal friends may not move the foam insulation around, but if an animal of a spray foam contractor sprays your foam you could have the same issue. I know of an attic (not mine of course) that has up to 9" of foam in some areas and as little as 0.5" in others. This could have the same effect.....could it not?

By: Allison Bailes

Allison Bailes — Mon, 28 Jun 2010 22:03:48 +0000

Elaine, yes, spray foam might
Elaine, yes, spray foam might help, but keeping animals out of the crawl space would be the first step. Depending on their house, they might also want to consider crawl space encapsulation.

Thanks, Paul & Jamie. It's just basic physics, but it surprises a lot of people to find out stuff like this.

By: Jamie

Jamie — Mon, 28 Jun 2010 21:37:53 +0000

Great stuff Allison.
Great stuff Allison.

By: Paul McGovern

Paul McGovern — Mon, 28 Jun 2010 15:51:20 +0000

Excellent commentary, Allison
Excellent commentary, Allison ... had assumed your conclusion but nice to have the equations to back it up ... attic stair insulation/encapsulation should be an easy sell.

By: Elaine

Elaine — Mon, 28 Jun 2010 15:27:06 +0000

I know a couple who had an
I know a couple who had an opossum in their crawl space and walls. The insulation under their floor sure did get moved around: it was lumpy.
Your math sounds like a good reason to get foam insulation, which is not likely to get moved around by our animal friends.