Foam insulation eating concrete!
On our last two houses we have had the exterior of the basement walls sprayed with 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. Of course they say there is no way.
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.
Replies
Strange. We've put closed cell foam both under and over concrete (before and after might be more accurate) all the time. Never seen or heard of this reaction. Installers should spray against a piece of plastic or cardboard on the floor to make sure the mix is good before spraying on the real substrate. If they do, there's almost no way to have unmixed liquid come out the nozzle.
In another life I worked as a materials engineer, and started out with a degree in chemistry.
There is nothing in sprayed foam, or the unreacted materials, that could react with concrete. That said, if you give me the actual type of foam, I will try to look up the ingredients and make a more specific comment. I would need at the least the trade name and the manufacturer.
Concrete is sensitive to being dissolved by acid. Perhaps someone did some acid washing and the residual acid was not removed.
The brand name was Demilec and I'd appreciate anything you could find out.
The one house was my own house and the spots on the concrete are small and don't bother me. The other house there are small spots and then two areas that are about 1 sq.ft. each. The homeowner luckily is understanding and is not making us cut out the affected sections. We are going to try and grind them down some how.
There would have been no acid washing going on that I know of. Unless the insulators do something with acid that I don't know about. Do they use it to clean their equipment?
>>Unless the insulators do something with acid that I don't know about. Do they use it to clean their equipment?
I was wondering the same thing. I might call the manufacturer directly with that question before asking your sub.
Acids are not used to clean equipment (that I've ever seen). The guns are cleaned with air purging, mechanically (poking and scraping), or with solvents. But solvents aren't used much. http://www.sprayfoam.com/spps/ahpg.cfm?spgid=11
Thanks for the link. I posted my question over there to see if they have ever run into this problem.
Closed cell polyurethene foam is totally inert once it cures - which is within three days, usually one. The only way it can be conected to this problem is to be trapping something under it that is harmfull to the crete
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Not trying to hijack or get off subject,but I poured a large sidewalk 10 years or so ago. A week or two later I get a call about brown bubbly spots on the walk. I go out to take a look and first thing I thought was someone had driven a piece of equipment over the walk that was leaking oil or hydraulic fluid or something. I started digging around one of the spots with a pocket knife and screw driver. Turns out the concrete truck had gone under a crab apple tree on the way in and the apples had dropped into the hopper.
Those things some how did not show up when the concrete was floated. I thing they were very close in size to the aggregate
Coca Cola or similar.
SamT
Now if I could just remember that I am a businessman with a hammer and not a craftsman with a business....."anonymous". . .segundo
Urethanes have an affinity for water when they are curing, that is why you wet the wood when you use urethane glue. If I remember correctly, the urethane insulation guns inject hot water at the nozzle, which is part of why it foams. The insulation might, and it is a big might, be pulling the water out of the concrete, but I would be surprised.
A more probable guess would be that it is pulling down into the concrete in pursuit of the water in the pores, (particularly if the concrete was recently placed). Then it is reacting with the water and expanding in the pores with enough strength to pop the concrete. Something similar to a sulfite/sulfate attack where the crystals forming in the pores of the concrete causes it to flake, and get soft.
If you can get them to give you some of the liquid before they spray it, you could test if by putting it on the concrete, and see what happens.
>the urethane insulation guns inject hot water at the nozzle, which is part of why it foams.No they don't.
Edited 12/21/2006 6:15 am ET by CloudHidden
It is one of the possible blowing agents used in the expansion.
It has been 20+ years since I was around one, but the last one I saw had a hot water feed.
"SPF is produced by a chemical reaction when two liquid components are combined, an isocyanate, known as the "A" component, and a polyol resin, known as the "B" component. When the two liquids are mixed together (typically at a one-to-one ratio), a chemical reaction occurs creating rigid, or semi-rigid foam."from sprayfoam.comDunno about 20 years ago, but today's spf's are a mix of isocyanate and a polyol resin. The hoses might be heated for smoother flow of the materials, but hot water is not a component.
The next paragraph from the spray foam site that you quoted:
When the liquids are mixed, they result in a thick amber colored mixture that reacts in seconds to form a light amber colored hard mass. As this reaction proceeds, a fluorocarbon or alternative (CFC, HCFC, H2O, hydro-carbon) propellant blowing agent is activated. The blowing agent causes the void volume to increase within the polymer. This blowing agent produces gas bubbles that become suspended in the silicone surfactant. The surfactant aids in mixing and controlling cell size. The bubbles trapped in the polymer cause the polymer to expand to about thirty times its original volume. This process produces a very light and durable solid polymer. Rigid foams are most commonly used for thermal insulation due to the gas trapped inside the closed cell bubbles.
Note the H2O, that is water.
Lets not get off on a side track. The question is what caused the concrete to deteriorate.
I stand with my suggestion, that one of the components leaked onto the concrete, which in a new house is still green. It then reacted with the pore water, and foamed with enough strength to break up the concrete.
It wouldn't attack the concrete blocks because: They were fully cured; and the pores are considerably larger.
Guys:
A year or so ago, I did a lot of work with a major foam supplier. Bottom line, water IS used as a blowing agent in some applications. Here's the deal: to make the foam, you need three things -- the part A and part B that combine to make the substance of the foam, and then a "blowing agent" to make it expand -- literally to inflate or "blow" the foam.
Blowing agents are closely regulated and usage is reported to an international body. Right now, blowing agents are in transiton due to to global environmental laws that are phasing out or have completely outlawed many of the old standards. Water, of course, does not pose an environmental risk, and is does perform reasonably well as a blowing agent under some circumstances although it is far from ideal for many reasons.
So, the answer is that Jigs-n-Fixtures is right, to a point, when he says that water is used. However, there are other blowing agents in use as well.
>Bottom line, water IS used as a blowing agent in some applications. Here's the deal: to make the foam, you need three things -- the part A and part B that combine to make the substance of the foam, and then a "blowing agent" to make it expand -- literally to inflate or "blow" the foam.Of course water is one of the blowing agents. But it's not used as was described earlier ("the urethane insulation guns inject hot water at the nozzle") or here. There's no hot water running through the hose to the gun. And water isn't added after A and B are mixed, or at least not in any use of spray polyurethane foam I've seen in the construction of houses.The blowing agent is part of the B side chemistry, as described here:http://www.sprayfoam.com/spps/ahpg.cfm?spgid=13"A typical polyurethane foam system consists of a multi-ingredient chemical formulation shipped in 55-gallon drum sets. Part A is a dark colored viscous liquid called isocyanate. Part B is commonly called the polyol resin. It is an amber colored viscous liquid that contains a polyether or polyester polyol, a blowing agent, silicone surfactant, and a catalyst.""When the liquids are mixed, they result in a thick amber colored mixture that reacts in seconds to form a light amber colored hard mass. As this reaction proceeds, a fluorocarbon or alternative (CFC, HCFC, H2O, hydro-carbon) propellant blowing agent is activated. The blowing agent causes the void volume to increase within the polymer. This blowing agent produces gas bubbles that become suspended in the silicone surfactant."The blowing agent causes cells to form via a chemical reaction and is part of the B side, not introduced separately. Have you ever seen hot water injected at the nozzle? Have you ever seen it used separate from the B drum?
Edited 12/22/2006 2:16 pm ET by CloudHidden
Look, I don't want to argue this, but to the guys who sell the stuff, like my client, part B refers to the chemistry of the foam. The blowing agent is NOT part B although it coes in the same tank as a rule. I am not aware of a system that adds blowing agent at the nozzle, although I am not an expert on that. I will tell you that nozzle technology is pretty specialized, and that the nozzles DO mix part A and part B.
It really is not that far from the mark to say the water is added at the nozzle, because regardless of where the water is stored, the mix of water and complete foam chemistry occurs at the nozzle.
You can read all you want on that web site, or you can take my word for it.
Jimminy Christmas. THis is a goofy argument.
>although it comes in the same tank as a rule.That's what I said. It's one of many ingredients in the goopy liquid that fills the B barrel. It's not a separately injected component.>You can read all you want on that web site, or you can take my word for it.Or I can take my own experience from having bought the stuff, talked to the owners and scientists, been in the plants, moved the barrels, sprayed the stuff, hauled the hoses, and cleaned the guns. Which matches what is said by the Spray Polyurethane Foam Alliance.And to think, this all started because someone said, "hot water is injected at the nozzle," and all I said was, "No, it's not.">I am not aware of a system that adds blowing agent at the nozzleGood. We agree.
I thought you were saying that water is not a blowing agent. And then I thought you were saying that blowing agent is component of part B.
I guess we agree that it IS a blowing agent sometimes, and that it is separate from part B even if it is in the same tank when delivered to the end user.
MERRY CHRISTMAS.
Over and out.
I think we can all agree that regardless of which elements were used for the foam, there is no way on earth for them to have done damage to a slab several feet away from the point of application on the opposite side of a block wall two weeks after the slab had been poured.
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ditto ditto dat.SamT
Now if I could just remember that I am a businessman with a hammer and not a craftsman with a business....."anonymous". . .segundo <!----><!---->
Back to the OP, maybe the fecal matter hit the rotary impellor and splashed on the new 'crete.
Soluble organics, sugared liquids, acidic sugared liquids, and strongly ph'ed liquids can all mess with concrete.
AFAIK, which ain't all that far, there are no restrictions between any spray foam and week old concrete.SamT
Now if I could just remember that I am a businessman with a hammer and not a craftsman with a business....."anonymous". . .segundo <!----><!---->
I fully understand that the foam, as shot from the gun, and neither of the components is reactive with the concrete. I have never said that the foam or either of the components reacted with the concrete.
One or both of the components is reactive with water. When it reacts with water, it foams and expands. (If you don't belive this and have access to the two components, Do the following experiment and let us know what happens: Get four mayonnaise jars, put a little warm water in the bottom of two mayonnaise jars, and drizzle one component in one, and the other component in the other, drizzle a little of each component into a jar by itself, set all four jars somewhere warm and look at them the next day to see what happened. )
This concrete was recently placed, less than 28-days, and green concrete contains a lot of pore water. This isn't big drops of water, it is distributed throughout the concrete in microscopic pores.
I feel that the deterioration of the concrete occured when, one of the components, penetrated into the concrete and reacted with the pore water. As it did, it expanded enough to break the concrete, causing the flaking, and softness.
If the OP wants to know for certain, he needs to get a little of each component from the applicator who did his work. Then call the concrete supplier, and find out where they are delivering the same mix design in the near future, and get that customer to let him have enough to make up a couple of 6-inch by 6-inch by test blocks. After they cure for a week, he needs to pour some of each component on the test blocks and see what happens.
One of the components is going to cause the flaking he has seen in his slab.
Hey All'y'all!
Except for the tempers, which I confess, I don't understand, This is a very informative thread.
I've enjoyed learning about sprayfoam.
So "Siddown, shutup, and keep talking!"SamT
Now if I could just remember that I am a businessman with a hammer and not a craftsman with a business....."anonymous". . .segundo <!----><!---->
Urethane foams aren't blown with water, nor were they twenty years ago. But even if they are or were, what would that have to do with "eating concrete?"
Blowing agents in the bad old days were CFCs, but now they are HCFCs or variations.
This thread ought to be closed down, or relegated to the "wierd science" or "alchemy" folders, which don't exist. Too many phonies with no knowledge of the materials are speaking off the cuff.
I think I'll start one titled, "Foam insulation eating my lunch!", see who chimes in with words of wisdom.
When I was a kid I tried to glue a broken Styrofoam lunch cooler back together with superglue and it dissolved the cooler. Does that count?
Are you related to frenchie?
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Frenchie, what's a frenchie?
Before this erupts into an arguement, it might be helpful to know the sequencing of th ejob.
Which came first of;
block wall
slab pour
spraying of insulation
and how long between each step.
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On the house that is the worst. Our mason had an opening in his shedule about two weeks before we were ready. So they laid the block and poured the floor. Then it sat for about two weeks before we had it insulated, began framing, and backfilled.
On the other house I would say the concrete had been done for about a week before it was insulated.
It is a really BIG stretch fro the scenario proposed by jigs... to happen to begin with, but bordering on the impossible for it to comeabout two weeks after the wall was laid and the slab poured.
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>to happen to begin with, but bordering on the impossible for it to comeabout two weeks after the wall was laid and the slab poured.My suggestion: the OP should commit a crime there. Call CSI, have them sample the material and run a gas chromatograph or whatever on the sample and then tell you what the heck it is.
I to, like JohnD1 , was a chemist in a prior life. Taught chemistry to engineering students and I agree with JohnD1 about the foam. I think that, between all the comments here, we have the answer. It's not the foam, it could be the concrete itself.
Question...what are the chances that the concrete in both locations is from bad batches or was mixed from the same plant originally? I've seen concrete that was contaminated at the time of mixing and it later crumbled with very little effort. I once worked on a job in San Francisco where the whole building was brick. The mortar used to set the brick was taken from the beach near by and, after 50 years, you could remove the mortar between the bricks with a plastic ball point pen. When they mixed the mortar they apparently didn't wash the salt out of the sand and it caused the mortar to weaken.
The concrete for both houses did come from the same plant. But they were at least a month apart.
That also doesn't explain the brownish spill streaks running down the block to the affected areas of concrete.