How can I remove cured spray foam residue from bricks after unsuccessfully sealing off a wasp nest inside wooden pillars?
Asked by Hazel Schaaij 
1 month ago
Last Updated: October 21, 2024
Hey everyone! So, I made a little mistake and could use some advice. Does anyone know how to remove cured spray foam from bricks? I tried using a wire brush drill attachment, but it didn’t quite do the trick. Here’s what happened: we had these wooden pillars with a ton of wasps inside, so I tried sealing it off with spray foam. Long story short, I ended up having to remove the posts to get rid of the nest. Now I’m left with some residue on the bricks that I want to clean up before putting the posts back. Any suggestions would be greatly appreciated!
I would think that a pressure washer might be a good option…
Sorry, doesn’t have the answer
Kevin s can help you out with that
Try using Muriatic Acid to scrub, it’s great for masons
Hey , thanks a lot! Should I plan on resealing the affected bricks afterwards, do you think?
Hey , I’d be quite hesitant to give that a try. It might end up discoloring the bricks, especially since they appear to have a light white wash finish.
https://m.supplyworks.com/#/sku/441223/great-stuff-12-oz-insulating-spray-foam-sealant-dispensing-gun-cleaner-074985005145-259205
Hey Kevin s, have you given this a shot on cured foam before? It claims to eliminate uncured foam but doesn’t mention anything about cured foam.
Shared how he used it on his gun that had foam on it for months
Acetone is definitely the way to go.
Your best option is to use acetone. Using muriatic acid incorrectly can damage the brick.
Gasoline
You can’t completely remove cured foam, especially from a porous surface. The instructions on the cans mention that. You’ll have to physically remove it, maybe with a wire brush and some elbow grease.
Get some muriatic acid from Lowe’s – then rinse it off using a garden hose.
Let’s increase the size of the posts from what they originally were.
I would be quite shocked if muriatic acid could penetrate this. It’s essentially HCL so it interacts effectively with concrete and mortar, but not with many other materials. Reminds me of high school chemistry class, learning about acids and bases.
Consider putting in a bigger post for better results.
Removing cured foam from a porous surface is extremely challenging, as you would need to grind it down so much that the grind marks become as noticeable as the foam itself. Using acid or gasoline will only worsen the situation by staining the bricks further. It might be easier to simply replace the post with a larger one and move on, rather than dealing with the headache.
A larger post is definitely your best option.
How about using acetone and scrubbing it with a stiff brush, then rinsing off the residue with muriatic acid and water
Should invest in a high-quality VOC respirator (a face mask with special filters). Remember to wear it consistently when using acetone. ‘t forget to protect your eyes. Some respirators even have full face shields. Make sure to wear gloves that are resistant to acetone. You can find all these supplies on Amazon.
Have you considered soda blasting?
You could give wd 40 a shot
Have you ever considered using muriatic acid or brick cleaner?