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bryce kennedy Posted: Mar 19, 2014 08:19 PM	crawlspace and basement encapsalation I posted this over at polyurea forums as well just wanted some opinions on this. Was just reading in spray foam magazine where they are using textile then spraying polyurea over it in basements and crawlspaces to become a VB, but then they spray pipes and seams etc. I see that could be a lot of bother to prep for. Then they spray closed cell over the polyurea as the final step. To me it seems like it would be better to forget the textile cloth and spray the foam direct to the dirt or concrete and then spray the polyurea over the foam if needed at all? Any thoughts?
mason Posted: Mar 20, 2014 10:54 AM	Nope wouldn't work. The vapor retarder membranes goes on first so that moisture from the ground doesn't travel into the insulation. Even closed cell foam will allow water vapor to migrate up. If you have the polyurea coated membrane over the foam, the foam can become saturated.
bryce kennedy Posted: Mar 20, 2014 01:20 PM	Thanks Mason makes sense. I am usually outside on the foundation walls. But how about after the floor level going to foam to create a good surface for the polyurea to stick to around pipes etc instead of crazy preparation?
mark moyer Posted: Mar 20, 2014 06:53 PM	mason,,,the vb control of closed cell foam only works in sidewall and ceiling assemblys then,,,but not on grade???? but 8 mil polysheeting works fine???? ..how bout,,, level grade in crawlspace...shoot 2.5-3" down on grade,,continue up sides and into box sill & rim joist assembly???coat with ignition barrier or thermal barrier coating,,or not,,, if required by design specs of crawl....will this do the trick???
jimcoler I have over 10 years of experience specifying and installing open and closed cell spray foam. I've sold my business but I'm still selling for the new owners and consulting on large and custom specific jobs. I've expanded my knowledge into t Posted: Mar 20, 2014 09:09 PM	I use Low-E reflective insulation for all crawlspace floors. It provides a great moisture barrier, and reflects the heat back up into the crawlspace. It comes with a double sided tape on one edge and we just peel it up and stick it down and off we go. It's about 3/16" thick closed cell polyethylene foam (recycled milk jugs) coated with a layer of foil on both sides. The plumbers and electricians love it when they have to crawl in there to do plumbing or wiring because it's clean, smooth, even cushioned, and you can slide around on it! It acts as a vapor barrier, insulation and radon retarder if it's sealed in with foam around the perimeter. And the nice this for the customer is it's inexpensive! You're looking at a decent profit if you install it for about $1-$1.50/sqft and it goes down very easy in 4' wide paths. So, email me if you want more info! jimcoler@yahoo.com
mason Posted: Mar 21, 2014 09:47 AM	Cuda, Yes, that would work, the high moisture content is typically in the ground. So, you can spray foam to the foundation walls, most likely they have been waterproofed on the outside to begin with and have a drainage tile system to take away water at the bottom of the foundation wall. For more info on basements and crawl spaces check out Joe Lstiburek's articles at buildingscience.com.
Greg Mitchell Posted: Mar 20, 2021 03:18 PM	Just noticed this forum discussing polyurea liners for crawlspaces. The initial reader misunderstood the article, which explains the polyurea is used to make liners / vapor barriers. It is installed over the ground and then seamed using polyurea. Spray foam is used in the sill boxes as insulation, and will not trap moisture. It is far better system than plastic and tape on the ground.

Author

Comments

bryce kennedy

Posted: Mar 19, 2014 08:19 PM

crawlspace and basement encapsalation

I posted this over at polyurea forums as well just wanted some opinions on this.
Was just reading in spray foam magazine where they are using textile then spraying polyurea over it in basements and crawlspaces to become a VB, but then they spray pipes and seams etc. I see that could be a lot of bother to prep for. Then they spray closed cell over the polyurea as the final step. To me it seems like it would be better to forget the textile cloth and spray the foam direct to the dirt or concrete and then spray the polyurea over the foam if needed at all? Any thoughts?

mason

Posted: Mar 20, 2014 10:54 AM

Nope wouldn't work. The vapor retarder membranes goes on first so that moisture from the ground doesn't travel into the insulation. Even closed cell foam will allow water vapor to migrate up. If you have the polyurea coated membrane over the foam, the foam can become saturated.

bryce kennedy

Posted: Mar 20, 2014 01:20 PM

Thanks Mason makes sense. I am usually outside on the foundation walls. But how about after the floor level going to foam to create a good surface for the polyurea to stick to around pipes etc instead of crazy preparation?

mark moyer

Posted: Mar 20, 2014 06:53 PM

mason,,,the vb control of closed cell foam only works in sidewall and ceiling assemblys then,,,but not on grade????
but 8 mil polysheeting works fine????

..how bout,,,
level grade in crawlspace...shoot 2.5-3" down on grade,,continue up sides and into box sill & rim joist assembly???coat with ignition barrier or thermal barrier coating,,or not,,,
if required by design specs of crawl....will this do the trick???

jimcoler

I have over 10 years of experience specifying and installing open and closed cell spray foam. I've sold my business but I'm still selling for the new owners and consulting on large and custom specific jobs.

I've expanded my knowledge into t

Posted: Mar 20, 2014 09:09 PM

I use Low-E reflective insulation for all crawlspace floors. It provides a great moisture barrier, and reflects the heat back up into the crawlspace. It comes with a double sided tape on one edge and we just peel it up and stick it down and off we go. It's about 3/16" thick closed cell polyethylene foam (recycled milk jugs) coated with a layer of foil on both sides. The plumbers and electricians love it when they have to crawl in there to do plumbing or wiring because it's clean, smooth, even cushioned, and you can slide around on it! It acts as a vapor barrier, insulation and radon retarder if it's sealed in with foam around the perimeter. And the nice this for the customer is it's inexpensive! You're looking at a decent profit if you install it for about $1-$1.50/sqft and it goes down very easy in 4' wide paths. So, email me if you want more info! jimcoler@yahoo.com

mason

Posted: Mar 21, 2014 09:47 AM

Cuda, Yes, that would work, the high moisture content is typically in the ground. So, you can spray foam to the foundation walls, most likely they have been waterproofed on the outside to begin with and have a drainage tile system to take away water at the bottom of the foundation wall.

For more info on basements and crawl spaces check out Joe Lstiburek's articles at buildingscience.com.

Greg Mitchell

Posted: Mar 20, 2021 03:18 PM

Just noticed this forum discussing polyurea liners for crawlspaces. The initial reader misunderstood the article, which explains the polyurea is used to make liners / vapor barriers. It is installed over the ground and then seamed using polyurea. Spray foam is used in the sill boxes as insulation, and will not trap moisture. It is far better system than plastic and tape on the ground.

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