# 2 part foam over fiberglass bats?



## beenthere (Oct 11, 2008)

Any pipes above the fiberglass?

Open or closed cell foam?


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## Windows on Wash (Aug 30, 2011)

Don't bother. It will be a mess.

You are far better served to cover the joists with rigid foam. 

Be sure to check with code enforcement in your are for what is permissible in terms of leaving the foam uncovered.


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## pbourquin (Mar 27, 2016)

beenthere said:


> Any pipes above the fiberglass?
> Minimal pipes above the fiberglass.
> 
> Open or closed cell foam?


Closed cell foam. Chosen for air sealing properties.


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## Bud9051 (Nov 11, 2015)

Hi pbour,
If you are doing what I gather from your description, I have to agree with WOW, yuck.
First, foam doesn't like to be installed thick. It has a limit where you must stop and allow it to cure before the next layer.
Second, to get good air sealing you would want the fiberglass out of the way.

Now, I'm not sure of your location, but in cold climates a crawl is often better off becoming part of the conditioned space, insulating and air sealing the perimeter instead of the floor.

Where are you?
Dirt floor or concrete?
Vented crawl?

Bud


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## Windows on Wash (Aug 30, 2011)

Bud9051 said:


> Hi pbour,
> If you are doing what I gather from your description, *I have to agree with WOW, yuck*.


Embrace it. The more you do, the easier it gets. 

:biggrin2::biggrin2:


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## beenthere (Oct 11, 2008)

pbourquin said:


> Closed cell foam. Chosen for air sealing properties.


Spraying over the fiberglass would mean the rim is not sealed. So it wouldn't air seal the house as much as you think.

Best to remove fiberglass and then spray.


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## Gary in WA (Mar 11, 2009)

Welcome to the forums!

I agree, we need the particulars... describe the joists as well- could be expensive foaming deep joists to decouple them from the ground; http://buildingscience.com/documents/insights/bsi-009-new-light-in-crawlspaces

Also, termites like foam, from what I've heard; http://www.termites101.org/termite-basics/termites-by-region

Gary


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