How do you dissolve cured expanding foam?

I am sorry to say it (maybe I am wrong), but if you want to get rid of
the bulge your best bet would be to remove the floor, remove the excess
foam with a hand grinder or similar tool and replace the floor.

There are some very strong "solvents" that will soften the foam, but it
sounds to me as though you have quite a bit of it between the wood
flooring and the concrete sub-floor and these solvents probably wouldn't
do you much good. E.g. even if you had something that worked, you'd
have to get rid of the solvent afterwards ;-)

Índice Show

Scrape, Saw, Pry
Acetone, Not H2O
Lacquer Thinner
How do you remove hardened spray foam?
Does WD 40 remove cured expanding foam?
How do I get rid of cured great stuff?

In plants and facilities where urethane foam is processed or
manufactured they soak machinery components in some pretty nasty
compounds such as DMF (dimethyl formamide?) or NMP (n-methyl
pyrrolidone) (90% sure I got the chemical names right). NMP is sold
industrially by BASF and maybe other chemical companies. Processors
(i.e. companies who use PU chemistry say for insulating, seating, etc.)
might soak machinery components that are gummed up with foam to clean
them. But as I said, these chemicals are pretty nasty, all they do is
soften the foam leaving a mass of gummy residual "gunk" and would not be
used to dissolve away a large quantity of foam. Also I would think it
extremely unlikely that these chemicals are available as a consumer
item.

If all you want to do is remove small specks or blobs that may be
sticking to the floor, you might try Polystrip or some commercial paint
removers, but I am not promising anything. You might want to call the
people at Mono - who knows do they have an 800 number or a web site :-)
- and ask their advice.

One other thing, shooting urethane chemicals "blindly" into a cavity may
be asking for trouble in another way: for instance if there was any
water in the gap, e.g. if the concrete was excessively damp, the foam
would likely be of very poor quality, would expand too much, and would
not adhere to the substrate (concrete).

In my opinion, any chemical solvent, even if you could get your hands on
a sample, is asking for more trouble, and you'd be better off removing
the bulging foam physically.

Regards,

Chris Kierans

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Polyurethane foam is more common than you may realize. It's used for support in your mattresses, chairs, car seats and for insulation in your walls. It's also found in sponges, medical dressings, large filters and soundproofing systems. Polyurethane plastic comes in a flexible foam form that can be applied with a spray can, which makes it easy to use for DIY projects. It is, however, irritatingly difficult to remove. Not only is the material stubborn and resistant, if removed the wrong way it can cause permanent wall damage. To remove unwanted foam, you'll need various tools and some elbow grease as you try scraping, sawing, prying and dissolving.

How to Dissolve Polyurethane Foam

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Scrape, Saw, Pry

First, check whether the foam has cured (dried). A noncured material may dissolve on its own over time – no chemicals or blades necessary. But, if the foam has cured, it's time to get out the tools. You can use a stiff-bristled or power wire brush to scrape off the foam and then rinse with water to remove any residue. For stubborn spots, you can use a reciprocating saw. Avoid cutting at a 90-degree angle so as not to ruin your wall, and steer clear of pipes and electrical lines. You can also go the prying route, using old claw hammers and pry bars. Older versions of these tools are preferable because the blunt edges will help avoid damaging the wall. Other tools that can be used for removing Polyurethane foam include a long-handled serrated trowel, a drywall saw and a wide-blade putty knife.

Acetone, Not H2O

Use acetone, which is found in nail polish remover, to clean off uncured wall foam. But, first, test it on a more discreet section of the wall to make sure it won't do any damage. Moreover, avoid cleaning with soap and water, as the moisture will make the foam cure and worsen the situation.

Lacquer Thinner

Lacquer thinner, which can be purchased at home improvement stores and online, should do the trick when it comes to removing cured wall foam insulation. Carefully follow the instructions provided on the label.

Take Heed

Don't, under any circumstances, apply heat to remove foam insulation. The foam contains many toxins that can be released into the air if heat is applied. When in doubt, call for professional help. It's better to err on the side of caution then cause damage to your wall or, worse, to your health.

How do you remove hardened spray foam?

Once the insulation has hardened, use a knife, saw, or another suitable tool to cut it out or pry it from the construction material. If you need to remove spray foam from a cavity (perhaps around a door), use a hammer or chisel to rip it out. Be careful not to damage any electrical wires that might be hiding behind.

Does WD 40 remove cured expanding foam?

Just pull out the straw from the foam can and spray in a little WD-40. It will breakdown the residual foam inside the straw. Wipe the applicator with a rag and repeat with the WD-40 until the foam is gone. Acetone can be used in lieu of WD-40, if you don't have any available.

How do I get rid of cured great stuff?

Let the great stuff completely cure for 24 hours and then take a hammer and beat it and try to break it down as much as you can and vacuum away all you can break off. The more you can remove with the hammer and vacuum the better. After that I would try some odorless mineral spirits(OMS).

dissolve cured expanding foam