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My crawl space has no insulation. The dirt is wet near one of the walls. There have been termites in the past.

I'm thinking of insulating the ceiling (between the joists) and the walls with foam spray. Am I on the right track with this idea? I hear that fiberglass is not a good idea because it can get affected by the moisture.

There are these products, such as Sealection500, Icynene, etc. Have people here used them? What's a good DIY product? There's foamitgreen.com and they offer the product and kit directly. I like that they are straight forward about it. Is that a good product though? Is the price good?


According to http://basementsolutions.blogspot.com/2009/11/do-not-spray-foam-your-crawlspace.html the walls should not be sprayed. Guess I can use rigid foam for the walls. Comments on that? How far down do you put the insulation on the walls? Down to the footing?

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Whatever material you consider beware that many (maybe even all - I don't know) types of polymer foam insulation are highly flamable and produce highly toxic material while burning. That's one of the factors to consider. – sharptooth Dec 24 '10 at 8:15
Ouch, didn't think of that. There's nothing else in the crawl space so I don't see how that thing would light up but that's a concern indeed. Now you scared me; should I not do it? – Peter Q Dec 24 '10 at 13:53
I found that some spray foams are fire rated, for example: tigerfoam.com/products.php They are specifically targeted towards commercial buildings that leave the foam exposed. – Peter Q Dec 24 '10 at 20:43
A fire retardant/proofer can be sprayed over any spray foam to give it a fire rating. Not sure if that is available DIY. – auujay Dec 27 '10 at 20:20
up vote 3 down vote accepted

There are some very good spray foams on the market. Most are a two part system and a starter kit runs around $800.00. This would include the hoses, tanks and spray wands and enough material to do several hundred square feet, depending on thickness. There are foams that are completely water and moisture resistant as well as mold and vermin proof. I sub out most of that type of work, so I don't have the brand names on the tip of my tongue, but you should be able to investigate various types of foam and equipment appropriate for your application at your local specialty distributor of insulation products.

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Also, check local codes - some places require that foam not be exposed, which means covering it up somehow - either framing/drywall or another, non-flamable coating sprayed over top the foam. – chris Dec 24 '10 at 12:35
Thanks! Any examples of non-flamable coating? – Peter Q Dec 24 '10 at 13:54
Chris is right on about some codes require covering foam. Here we have different requirements for single family residential vs multi-unit rental properties. Here we are allowed to use foam or rigid foam board in crawl spaces uncovered, but have to cover foam in basement floor joist boxes with sheetrock. – shirlock homes Dec 25 '10 at 12:58
Shrilock, thanks for the comment. I'm thinking to do it like that, I'll have to check the codes I guess (not really sure where to look though) – Peter Q Dec 25 '10 at 19:34
Peter, don't be afraid to call your local code enforcement office and ask specific questions. They can be of great assistance in answering questions or clarifying gray areas before it becomes an issue later. – shirlock homes Dec 26 '10 at 1:44

Use rigid foam insulation for the walls. You may not even need insulation for the ceiling especially if you put vapor barrier on top of the ground.

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I'd be more concerned with the moisture getting in and the possibility of termites. Where is water coming in and can it be stopped? I'd be more afraid of the insulation getting wet and then moldy causing a much bigger problem in the future.

As for the possibility of termites, I'd also get that checked into right quick. You don't want termites eating away at your joists. Get an exterminator in there to check and kill whatever might be in there.

I'm not sure of a good sprayform insulation but it sounds like you might have bigger issues with moisture and bugs before needing to spray first.

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I did inspect for termites and I don't have any at the moment. The expert advised me to put some sort of vapor barrier but my understanding it is not that great. – Peter Q Dec 24 '10 at 13:47
I can take care of the water by digging a trench around the crawl space perimeter with gravel and a pipe that leads to a sump pump. – Peter Q Dec 24 '10 at 13:48

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