Yes, you can remove spray foam insulation yourself, but it is a labor-intensive and incredibly messy process. Open-cell foam is softer and relatively easy to tear off, whereas closed-cell foam cures hard and strongly bonds to surfaces, making it very difficult to remove without damaging the underlying structure.
The easiest way to remove spray foam depends on its state: for uncured foam, immediately dissolve it using Great Stuff Pro Foam Cleaner or acetone. For fully cured foam, mechanical removal using a scraper, flathead screwdriver, or a wire brush/flap disc on a drill is required.
WD-40 does remove expanding foam, but only if the foam is uncured. It acts as a solvent to break down the sticky polyurethane before it hardens. Once the foam is fully dried and cured, WD-40 will not dissolve it, and you will need to rely on physical scraping or cutting methods.
However, for cured foam, natural alternatives are significantly less effective. Oils and vinegar can help soften hardened foam slightly, but mechanical or chemical methods, such as acetone or WD-40, are far more reliable for complete removal.
People remove spray foam insulation primarily because poor installation or improper use traps moisture. This hidden condensation causes severe wood rot, mold growth, and pest infestations. Additionally, the inflexible barrier can strain roof timbers and prevent surveyors from assessing the home's structural condition, which often leads mortgage lenders to reject loans.
Spray Foam Remover
Isopropyl Alcohol: It is not as strong as acetone but it will help, especially on wet foam. It will dissolve the foam before it hardens.
Removing spray foam insulation typically takes between 1 to 5 days, depending on the size of the area, the type of foam, and whether you do it yourself or hire a professional.
Yes, spray foam is considered a permanent insulation solution. Once applied, it expands and hardens into an airtight seal that does not settle or compress over time. Depending on the type, it can last anywhere from 30 to 100+ years, often outliving the building itself.
It is not recommended to be in the house while spray foam is being actively applied. Most manufacturers and the EPA recommend vacating the home and keeping pets out for a minimum of 24 hours to allow the foam to cure and any off-gassing to safely dissipate.
Buyers often walk away from homes with spray foam insulation because it can cause major mortgage and insurance denials. The foam tightly seals roof spaces, trapping moisture, and covers up structural timbers. This makes it impossible for surveyors to inspect for hidden rot or damage, which can lead to catastrophic repair costs.
Do not use WD-40 on sensitive electronics, door locks, certain plastics, wood, rubber seals, or food-contact surfaces. Because it is primarily a solvent and water-displacer, it can wash away factory lubricants, degrade materials, or leave a sticky residue that attracts dirt over time.
Yes, gasoline will dissolve uncured (wet) spray foam and polystyrene (Styrofoam). However, it does not dissolve cured polyurethane spray foam (like Great Stuff).
The government has also stated that, where spray foam insulation has been installed in line with the relevant standards, it should not require removal or prevent homeowners obtaining a mortgage.
Acetone is the most effective common chemical for dissolving polystyrene (Styrofoam) and uncured polyurethane spray foam. It works by breaking down the polymer chains, turning the foam into a dense, liquid gel almost instantly. Other effective solvents include lacquer thinner, toluene, and ethyl acetate.
Expert Verdict: While technically possible for a homeowner to scrape away foam, it is not recommended. Professional removal is the only way to ensure the roof is “mortgage-ready.” In most cases, professional spray foam removal is the safest and most effective solution.
Yes, mold can grow under or behind spray foam. While spray foam itself is an inorganic material that cannot be used as a food source by mold, it will grow if it traps moisture, has a nutrient source (like wood or drywall), and is left in the right temperature range.
Insulating a 2,000 sq. ft. house with spray foam typically costs between $𝟑,𝟎𝟎𝟎 and $𝟏𝟐,𝟎𝟎𝟎, depending on the areas you treat. Expect to pay an average of $𝟏.𝟓𝟎 to $𝟓.𝟓𝟎 per square foot of surface area.
Closed cell spray foam is rigid once set. It is a better thermal insulator and was previously sold to stabilise failing roofs. But if it has been used inappropriately or installed poorly, it might put stress on timbers, restrict air circulation and put them at risk of decaying.
Yes, mice can easily chew through foam insulation. Foam lacks structural integrity, and its soft texture makes it a prime target for rodents looking to create nesting tunnels or sharpen their teeth.
The healthiest insulations for a house are natural, bio-based materials that offer excellent thermal performance without off-gassing toxic chemicals. The safest and most non-toxic options available are sheep's wool, hemp, cotton (denim), and cork.
Spray foam insulation is designed to be a permanent, "set it and forget it" solution. When properly installed, it can last between 80 to 100 years. It does not sag or settle over time, maintaining its insulating power for a lifetime.
No, spray foam is generally not easy to remove. Because it is designed as a permanent, high-adhesion insulator, hardened foam requires significant physical labor and specialized tools to strip away without damaging the underlying structure.
Yes, mice absolutely love blown-in fiberglass insulation. It provides a soft, warm, and highly structured environment for nesting, tunneling, and breeding.
Adding more insulation does not always make a house warmer because insulation only slows heat transfer. Homes with major air leaks, moisture problems, unsealed rim joists, or empty wall cavities can still feel cold even with attic insulation rated at R-38 or R-49.