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We are in Los Angeles and have built a 22'x28' two-story building in the yard. Should we use open- or closed-cell insulation?

This will be used as a laundry room, office and in the loft sleeping for two teen-aged boys. The weather is generally good in Los Angeles although I am only 3 miles from the ocean. I have read so much but am not sure whether to put open or closed cell insulation. Help!

Asked by Sheila McCoy
Posted Feb 21, 2011 7:57 PM ET
Edited Feb 22, 2011 4:43 AM ET

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5 Answers

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1.

I don't see much appeal in open-cell foam. It does serve as a good air barrier, but I think you can achieve that in other ways. Assuming you have 2x6 walls, you could consider dense-pack cellulose there, and maybe closed-cell foam for the roof, if it's a cathedral design. If you have an attic, I would use cellulose there too, and skip the foam.

As with all projects, air-sealing is really critical. I see tons of mistakes being made in new construction in this regard. Before you continue with the project I suggest you read everything you can on the topic. Most or all of what you need is right here on this site. It sounds like you already have the building standing, so you're about due for your first blower door test.

Answered by David Meiland
Posted Feb 22, 2011 1:24 AM ET

2.

Sheila,
Either foam will work fine, if spray foam is what you want. The skill of the installer matters much more than the type of foam you choose.

As David pointed out, there are other choices besides spray foam you might want to consider.

Answered by Martin Holladay, GBA Advisor
Posted Feb 22, 2011 4:45 AM ET

3.

i'm not familiar with your zone but my first guess would be open cell foam. I'm in zone 5A and use open cell in buildings like that every day more so than closed cell.
Do not take advice directly from me or anyone else answering here. We could all be maniacs! Do your own research and find a local foam guy you trust out there in LA.

Answered by Stuart Fearn
Posted Feb 22, 2011 7:28 AM ET

4.

Thank you so much for responding. So far, you are the nicest maniacs I have met lately. I think we are going with open-cell. My daughter lives about 3 miles from the ocean but it is not really damp. I realize that the skill of the installer is most important. Thank you, thank you. Sheila

Answered by Sheila McCoy
Posted Feb 22, 2011 12:01 PM ET

5.

Stuart,

The advise given by Martin and David should most definitely be taken.

Answered by Brett Moyer
Posted Feb 22, 2011 7:03 PM ET

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