How to Remove Expanding Foam

Expanding foam is an incredibly useful piece of kit for bonding, insulating, soundproofing and more. The downside is that it’s an almighty pain to get rid of, as anybody unfortunate enough to spill it knows!

Whether you’ve got foam expanding somewhere it shouldn’t or you’re removing fixtures as part of other work, there are ways to get rid of this stubborn substance, most of which involve a combination of cutting and chemicals.

What You Need to Remove Expanding Foam

How you should remove expanding foam depends on various factors, such as how hardened the foam is and what surface it’s on. However, it’s a good idea to have these things close to hand:

• An oily cloth (such as baby wipes or a normal cloth with vegetable oil)
• A precise blade (such as a razor or carpet knife)
• Sanding tools (sandpaper, wire brush etc.)
• A blunt blade (such as a plastic spatula)
• Expanding foam remover
• Personal Protective Equipment (PPE)

Step 1: Cut it Back

Assuming you’re dealing with expanding foam that has already started to harden, the first step is to cut off as much as you can. Expanding foam is usually quite easy to cut with a sharp blade. However, you need to be careful to not damage surrounding surfaces.

1. Use a small, sharp blade to cut away at the largest sections of expanding foam.
2. Once most of the easy foam is removed, swap to sanding paper to remove more, getting as close to the surface as possible. If you’re working with a hard surface, such as stone or metal, you could even use a wire brush.

Step 2: Use Chemicals

Once you’ve removed as much as you can through cutting and sanding, you can then turn towards more chemical options.

It is possible to purchase tailor-made expanding foam remover. However, you can also use other solvent cleaners such as acetone (found in nail polish remover and paint thinner) and WD-40. The strength of the chemical you choose to use will depend on how hard the foam is to remove, as well as the surface it is stuck to.

1. If possible, score the remaining foam to help the chemical penetrate.
2. Apply the chemical foam remover and leave to work for as long as recommended (expanding foam removers usually suggest around 30 minutes, but check your product’s instructions).
3. Remove the loosened expanding foam with a blunt plastic object, such as a spatula, to avoid damaging the surface.
4. Wipe the area clean with a cloth.
5. If some expanding foam remains, repeat this process until it has all been removed.

Tips for Removing Expanding Foam

• Act Fast: If possible, remove expanding foam before it has a chance to set. If it spills, wipe it up with an oily cloth immediately.
• Protect Skin and Textiles: If expanding foam falls on you, there’s not much that can be done to remove it entirely. Your skin will need to heal naturally over time (moisturising can help), while it’s almost impossible to remove the foam from textiles, which is why you should always wear PPE.
• Take Care When Working on Wood: Because wood is porous, expanding foam is particularly difficult to remove here. You may need to sand down the wood and then repaint or revarnish.
• Test on Concealed Area First: Removing expanding foam through cutting and chemicals can sometimes damage the surfaces or leave discolouration, so it’s always best to start on a concealed area first.

As you’re probably aware, removing expanding foam can be a pain. However, taking the time to follow this method should help you get rid of the stuff with minimal damage.