Is spray foam insulation in an attic worth it?

Author: Miss Erica Schimmel I  |  Last update: Friday, May 22, 2026

Spray foam is an ideal choice for insulating the floor of the attic because it is air impermeable and a powerful insulator. This will keep conditioned air in the living area of the home, and the warm or cool air in the attic from entering the home where it can cause condensation, mold and other problems.

Is it worth it to spray foam your attic?

Pros of spray foam insulation

It can last for up to 80 years. It can help keep rodents and other pests out of your home. It can discourage bats too, but if you have an existing colony in your home you will need to get a specialist to remove it before using spray foam insulation.

What is the downside of spray foam insulation?

Spray foam insulation is a good insulator in terms of keeping a room warm or cool. But its many downsides outweigh the benefits. These include, making it more difficult getting a mortgage, potential health issues, environmental damage, ventilation issues and a lower home valuation.

Why is spray foam a red flag for lenders?

Spray foam insulation is one of those many factors that can throw up a red flag to a mortgage lender. For a lender, your insulation matters because it affects crucial metrics such as the home's saleable value and energy efficiency rating.

How much does it cost to spray foam an existing attic?

Project Size and Insulation Location

For example, using open-cell spray foam, the attic spray foam insulation cost is between $3,500 - $5,000, while closed-cell spray foam costs range from $4,500 to $7,000 for the same project size.

What is the Best Attic Insulation? (Spray Foam vs. Fiberglass vs. Cellulose) | Foam University

When not to use spray foam insulation?

Directly against electrical wiring or fixtures: Spray foam insulation should not be applied directly against electrical wiring, fixtures, or recessed lighting unless they are rated for contact with insulation. Contact with insulation can cause overheating and pose a fire hazard.

Why is it hard to sell a house with spray foam insulation?

Some Buyers May Be Uncertain Of Spray Foam Insulation.

If they don't know the contractor who installed it, they may worry that the foam was installed by people who didn't know what they were doing. Other buyers have heard negative stories about spray foam insulation.

Why do insurance companies not like spray foam insulation?

The chemical aspect of spray foam makes it very hard for standard insurance companies to provide coverage. Most standard lines insurance carriers want to write the risks with no liability not spray foam contractors that manufacture plastic every day in the field.

What not to tell a lender?

5 Things You Should Never Say When Getting a Mortgage
  • 'I need to get an extra insurance quote due to … ...
  • 'I can't believe how much work the house needs before we move in' ...
  • 'Please don't tell my spouse what's on my credit report' ...
  • 'I'm still working out the details on my down payment'

Can mold grow behind spray foam insulation?

Mold and mildew can begin growing behind the insulation which can go unnoticed until it's already become a huge problem. This often happens when the spray foam isn't installed correctly and space is left between the insulation and the wall, which allows moisture in and gives mold the perfect place to grow, unfettered.

What is better than spray foam insulation?

While both types of insulation are great choices for home insulation, fiberglass insulation is generally considered to be safer than spray foam insulation. This is because spray foam contains a special type of chemical called isocyanate, which is toxic when inhaled.

Where not to use expanding foam?

While it is hugely useful, it should not be used to solve all problems. One such example is electrical boxes. Expanding foam shouldn't be used in these locations as it could cause jams that would be expensive to repair. So avoid using it around sockets or light fixtures, or any electrical components in the property.

What are the negatives of spray foam?

Addressing the question of "what are the disadvantages of spray foam insulation" requires a balance between acknowledging its drawbacks and providing solutions to mitigate them.
  • Health Concerns. ...
  • Cost Factors. ...
  • Installation Complexities. ...
  • Potential for Mold Growth. ...
  • Respiratory Difficulties and Off-gassing. ...
  • Long-term Effects.

Do you need an attic fan with spray foam insulation?

Proper Attic Ventilation

Without ventilation, moisture can accumulate and cause mold, mildew, or damage to the roof. If spray foam is instead applied to the attic ceiling, ventilation may not be needed. An exception is with wood, tile, slate, or some asphalt shingle roofs that require an air gap for their warranties.

What is the best insulation for an attic?

Why Fiberglass Batt Is the Best Attic Insulation Material. Fiberglass batt is considered to be the best insulation for attics.

How much does it cost to foam insulate an attic?

To give you an idea, the average cost to spray foam an attic in an existing home typically ranges from $5,100 to $10,300.

Does spray foam decrease home value?

Spray foam insulation provides an excellent air seal, reducing the workload on the HVAC system by minimizing air leaks. This not only extends the lifespan of the HVAC system but also improves comfort and energy efficiency, qualities that can boost a home's marketability and resale value.

Why are lenders rejecting homes with spray foam?

Some mortgage firms are reluctant to deal with homes with spray foam insulation due to concerns over poor fitting leaving moisture trapped and roof timbers at risk of decay.

Does homeowners insurance cover attic insulation?

If the attic damage was caused by a covered risk, such as fire or wind, your home's insurance policy may pay the cost of rehabilitation. Repairing or replacing damaged insulation, drywall, and other materials could be included.

What is the R-value of spray foam in the attic?

Closed cell spray foam has an R-value of R-7 per inch. In comparison, open cell spray foam has an R-value of R-3.8 per inch.

Is it worth spray foaming an attic?

Spray foam insulation is a better insulator than traditional insulation. One of the most significant advantages of spray foam insulation is that it is a better insulator than other types, meaning homeowners can save money on their heating and cooling bills.

What is the best alternative to spray foam insulation?

Instead of spray foam, Curtis recommends cotton denim insulation, which is typically made from industrial scraps.

Should I spray foam the underside of my roof?

Spray foam can provide the thermal, air, and vapor control layers in both new and retrofit construction. Unvented roof strategies with open cell and closed cell SPF insulation sprayed to the underside of roof sheathing have been used since the mid-1990s to provide durable and efficient building enclosures.

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