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E Chernicky Posted: Dec 20, 2006 11:52 AM	Foam insulation eating concrete? On our last two houses we have had the exterior of the basement walls sprayed with Demilec closed cell foam. On both of the houses the basement slab has spots where the concrete has been eaten away like acid was poured on it. It's not just that the concrete is pitted, in some places it's actually "bubbled" up. The only thing we can think of is that it is caused by one of the foam chemicals. The installer says no way. It's not from them. On both jobs there are brownish spots on the inside of the concrete block wall like something was spilled down the wall. Then when it gets to the concrete it looks like it puddled and started to eat away. Has anyone seen this? I can't understand how it would not affect the block but then be so destructive to the concrete. I would assume it's one of the chemicals just not mixing completely with the other at the beggining of spraying. I'm not the installer, but the builder.
Posted: Dec 20, 2006 06:55 PM	got any pictures?
Gerry Wagoner Posted: Dec 20, 2006 08:45 PM	Dear Cinc: What you describe is nearly impossible with urethane foam. To etch the concrete, a material would have to be completely on the acid side of the PH scale. Spray foam is not. We have (on occasion) spilled both chemicals on concrete floors in our shop. No problem, except for the staining that iso makes. I wonder if the brick was acid washed? A heavy concentration of acid could etch the alkaline based concrete. Freezing water on top of the concrete will do the same thing (cause serious spalling) within 30-days of the pour. Let us know if you discover the cause, olger
Posted: Dec 21, 2006 02:04 AM	foam on exterior spots on interior... what olger said..... will check with the concrete buds on possible causes of "spalling" i spray foundation exteriors, interiors, underslabs for radiant floor heat/insulation.. and have not seen this,,,ever... (it is interesting that other trades will blame the "new product" for their failures,,,have had cement contractors try this in the begining..the foam cant help that the slab "got away from them"..had one blame the foam for cracking of the cement...go figure,,by the way,,he lost the battle) :)
Dave Strnad Posted: Dec 21, 2006 06:29 AM	Is there residue on the the block wall and floor or is it just discolored? If it was unmixed foam that ran down the wall the foamer would be able to tell within a second of looking at it. Also how big of a spot are you talking about?
E Chernicky Posted: Dec 21, 2006 01:44 PM	There was no acid washing that took place. This was jsut a basement with concrete block, no brick. On the block there are brownish streaks running down the inside to the floor. On the floor there are several small areas maybe an inch around. But on the one house there are two very large areas that are about 1sq.ft. each and if you put a straightedge over these spots they have "bubbled" up enough to be higher than the surrounding smooth concrete. I'll try with the pics.
SprayFoamSupply.com Posted: Dec 21, 2006 11:31 PM	Are the bubbled up spots brownish in color? Sounds like ISO that has hardened up. It is hard like concrete, but couldn't affect the concrete, other than maybe, maybe a stain. Get a belt sander with a 60 grit belt and try to sand it off. Make sure you wear a respirator. Are the brownish streaks running down hard as well? George
E Chernicky Posted: Dec 22, 2006 01:48 PM	The spots on the floor aren't brown. They're just concrete color. The streaks on the wall are stains only. Like someone dumped a dark brown wood stain down the wall and it soaked into the block pores a little. We did use a scraper on some of the smaller spots and they will scrape off, but you can tell something was there. The large spots are untouchable, a scraper does nothing and a belt sander would be shredded very quickly.
Posted: Dec 22, 2006 04:47 PM	the stains sound like iso,,, ???guy's would a soaking with dynasolve bring it loose???
Posted: Dec 22, 2006 04:49 PM	oh yeah,,, ive had resin and iso on the shop floor too... and its a mess,, but it never has messed with the floor at all..
Dave Strnad Posted: Dec 22, 2006 09:45 PM	It could be possible that the raw materials could affect green concrete. They react with water and concrete cures by forcing the water out. Unlikly though, also unless some major equipment or operator failure I can't imagine that enough iso or resin would be all over to cause such a problem.
Aaron Scurlock Posted: Jan 02, 2007 02:34 PM	Most likely has nothing to do with the foam at all?

Author

Comments

E Chernicky

Posted: Dec 20, 2006 11:52 AM

Foam insulation eating concrete?

On our last two houses we have had the exterior of the basement walls sprayed with Demilec closed cell foam. On both of the houses the basement slab has spots where the concrete has been eaten away like acid was poured on it. It's not just that the concrete is pitted, in some places it's actually "bubbled" up.

The only thing we can think of is that it is caused by one of the foam chemicals. The installer says no way. It's not from them.

On both jobs there are brownish spots on the inside of the concrete block wall like something was spilled down the wall. Then when it gets to the concrete it looks like it puddled and started to eat away.

Has anyone seen this? I can't understand how it would not affect the block but then be so destructive to the concrete. I would assume it's one of the chemicals just not mixing completely with the other at the beggining of spraying.

I'm not the installer, but the builder.

Posted: Dec 20, 2006 06:55 PM

got any pictures?

Gerry Wagoner

Posted: Dec 20, 2006 08:45 PM

Dear Cinc: What you describe is nearly impossible with urethane foam. To etch the concrete, a material would have to be completely on the acid side of the PH scale. Spray foam is not. We have (on occasion) spilled both chemicals on concrete floors in our shop. No problem, except for the staining that iso makes.

I wonder if the brick was acid washed? A heavy concentration of acid could etch the alkaline based concrete. Freezing water on top of the concrete will do the same thing (cause serious spalling) within 30-days of the pour.

Let us know if you discover the cause,

olger

Posted: Dec 21, 2006 02:04 AM

foam on exterior
spots on interior...
what olger said.....

will check with the concrete buds on
possible causes of "spalling"

i spray foundation exteriors, interiors, underslabs for radiant floor heat/insulation..
and have not seen this,,,ever...

(it is interesting that other trades will blame the "new product" for their failures,,,have had cement contractors try this in the begining..the foam cant help that the slab "got away from them"..had one blame the foam for cracking of the cement...go figure,,by the way,,he lost the battle) :)

Dave Strnad

Posted: Dec 21, 2006 06:29 AM

Is there residue on the the block wall and floor or is it just discolored? If it was unmixed foam that ran down the wall the foamer would be able to tell within a second of looking at it. Also how big of a spot are you talking about?

E Chernicky

Posted: Dec 21, 2006 01:44 PM

There was no acid washing that took place. This was jsut a basement with concrete block, no brick.

On the block there are brownish streaks running down the inside to the floor. On the floor there are several small areas maybe an inch around. But on the one house there are two very large areas that are about 1sq.ft. each and if you put a straightedge over these spots they have "bubbled" up enough to be higher than the surrounding smooth concrete.

I'll try with the pics.

SprayFoamSupply.com

Posted: Dec 21, 2006 11:31 PM

Are the bubbled up spots brownish in color? Sounds like ISO that has hardened up. It is hard like concrete, but couldn't affect the concrete, other than maybe, maybe a stain. Get a belt sander with a 60 grit belt and try to sand it off. Make sure you wear a respirator. Are the brownish streaks running down hard as well?

George

E Chernicky

Posted: Dec 22, 2006 01:48 PM

The spots on the floor aren't brown. They're just concrete color.

The streaks on the wall are stains only. Like someone dumped a dark brown wood stain down the wall and it soaked into the block pores a little.

We did use a scraper on some of the smaller spots and they will scrape off, but you can tell something was there. The large spots are untouchable, a scraper does nothing and a belt sander would be shredded very quickly.

Posted: Dec 22, 2006 04:47 PM

the stains sound like iso,,,
???guy's would a soaking with dynasolve bring it loose???

Posted: Dec 22, 2006 04:49 PM

oh yeah,,,
ive had resin and iso on the shop floor too...
and its a mess,,
but it never has messed with the floor at all..

Dave Strnad

Posted: Dec 22, 2006 09:45 PM

It could be possible that the raw materials could affect green concrete. They react with water and concrete cures by forcing the water out. Unlikly though, also unless some major equipment or operator failure I can't imagine that enough iso or resin would be all over to cause such a problem.

Aaron Scurlock

Posted: Jan 02, 2007 02:34 PM

Most likely has nothing to do with the foam at all?

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