How to Remove Spray Foam Insulation

Spray foam insulation is a helpful product that lets you plug gaps in your insulation around door frames and windows, reducing your bills. Unfortunately, it has an annoying habit of getting places you don’t want it to. And when it does, it is difficult to remove. 

If you make a small mistake, you can usually remove it by hand. For more significant errors, you’ll need the help of an insulation removal machine. We discuss both methods below:

Manual Removal Of Spray Foam Insulation 

For this article, we’re going to assume that you need to remove spray foam from construction materials, not your clothing or body. 

Step 1: Fit A Mask

Spray foam is pretty nasty stuff, chemically speaking. It contains a combination of isocyanate and polyol resin. When these two chemicals react, they expand in a way that doesn’t allow air to infiltrate the interior foam, creating a thermal barrier. They then harden into a solid residue and provide long-term protection against heat loss. 

So long as you don’t disturb them, they are safe. However, when you remove foam manually, particles can get into the atmosphere and your lungs, so wearing a face mask is essential. 

Step 2: Let The Insulation Dry Out

If you’ve just applied the insulation and made a mistake, don’t remove it immediately. Instead, wait for it to dry out first. As it hardens, it will become easier to remove. 

Step 3: Cut Through The Excess Insulation

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.

Step 4: Remove Remaining Spray Foam With A Hard-Bristled Brush

If you need to get more spray foam out of the cavity but can’t with the tools mentioned above, try using a hard-bristled brush or paint scraper. Rubbing the offending site with these tools removes remaining layers of foam on brick, wood, or concrete fast. 

Sometimes, you may need to experiment with differently-sized brushes to get into all the nooks and crannies. Keep brushing meticulously. If you can’t remove everything in a single session, go back to it later. 

Step 5: Apply Lacquer Thinner

Once you’ve removed the lion’s share of the spray foam, you might want to apply lacquer thinner. 

Lacquer thinner is a unique solvent that can dissolve uncured polyurethane-based products. Professionals like to use it to finish up removing insulating foam once all the larger particles are gone. 

If you don’t have any lacquer thinner to hand, you can use nail polish remover. It contains acetone, which will also dissolve uncured polyurethane foams. 

However, please note that neither lacquer thinner nor nail polish remover will get rid of cured foams. 

Step 6: Clean Up The Mess

The final part of the process is to clean up the mess. If you only needed to remove a small amount of spray foam insulation, a dustpan and brush will suffice. Any more than that, and you’ll need a heavy-duty solution. 

Machine Removal Of Spray Foam Insulation

If all that sounds like a lot of work, then you’re right. Even removing a small quantity of errant spray foam by hand is a mammoth undertaking. Fortunately, there are now many machines that will do the job for you, saving you a tremendous amount of time. 

Step 1: Put On Your Mask

As before, you’ll need a mask to prevent errant particles from getting into your lungs. 

Step 2: Connect The Vacuum Hose To The Spray Foam Removal Machine 

The next step is to set up your spray foam removal machine to remove the offending insulation from the affected area conveniently. 

Spray foam vacuum units are substantial (because of the power that they need to generate). So it is impractical to move them into some areas, like attics. Fortunately, most come with expandable hoses. Like giant vacuum cleaners, you can run through a building and place precisely where you need them. 

Attach the hose to the central unit and then run it through to the area you need it. At the same time, attach the vacuum bag to catch all the material you eventually slurp up. 

Step 3: Chip Offending Foam From The Wall (If Required)

While these vacuum systems are powerful, they’re not sufficient to literally suck dried on foam from your building materials. Therefore, you will need to chip off the offending foam from the walls using the method described above. 

Step 4: Vacuum The Old Insulation

The next step is to vacuum all of the insulation material. 

Spray foam removal machines are, essentially, large and extremely powerful vacuums. Removing damaged or improperly applied insulation is usually a time-consuming task. But these pieces of equipment shorten the process dramatically. Ridding an attic of moldy or damaged insulation just takes a few minutes instead of several hours, allowing you to apply the new material in the space of a single visit, slashing your costs. 

Step 5: Apply Lacquer

As before, simply apply the lacquer thinner to any remaining spray-foamed surfaces, and you’re done. If you’re removing regular foam, you can skip this step. 

Wrapping Up

Removing spray foam from building materials can be a bit of an ordeal. If it’s a small job, you can usually do it by hand. Fixing a bit of misplaced foam is usually a minor job. Sorting out more substantial errors, however, requires the use of specialized vacuum machinery. Otherwise, you can find yourself wasting days of your life, simply collecting foam from attic floors or wall cavities. 

Please note that if you get spray foam insulation on your skin, remove it immediately while it is wet. Just rub down the spray foam with a dry rag and add acetone to the affected area to remove the residue. Some people like to add moisturizer to keep the skin supple. 

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