DIY Spray Foam Insulation: Types, Installation Tips, and Safety Precautions

From sealing air leaks to lowering energy bills, insulation is a homeowner’s best friend. While DIY spray foam insulation is excellent for use almost anywhere around a home, there are some limitations to consider.  

Learn the ins and outs of do-it-yourself spray foam installation, what kinds and kits are available to consumers, and whether or not tackling this task is right for you.  

Types of Spray Foam Insulation

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Before you get started on your home insulation installation project, consider that not all types are available to DIYers. 

While there are several types on the market, only a limited few are available for use as a DIY spray foam insulation product. 

Polyurethane Spray Foam Insulation

Polyurethane is the most common type of spray foam insulation available. The familiar and useful spray-paint-size cans of low-expansion gap filler and sealer are most often polyurethane spray foams. 

In the world of home insulation, polyurethane spray foam is available in two-part, closed-cell, or open-cell varieties that only professional installers can get a hold of in bulk. For the rest of us, closed-cell spray foam insulation is available in kits at your hardware store, home center, or other retailers.

Plant-Based Spray Foam Insulation

Some professional spray foam insulation companies near you will use foam made from either soybeans or vegetable oil. It’s not yet available in a DIY form, but in some locations, companies who advertise as green building operations can install it for you. 

Water-Based Spray Foam Insulation

Although not common, you can find water-based spray foam sealers to fill gaps around windows, doors, and plumbing in small, disposable cans. Green building companies also may offer a water-based spray foam solution that they can install on a larger scale.

Spray Foam Insulation Cost

In order to talk about spray foam insulation costs, it’s important to understand how to measure the quantities in board feet instead of the square feet associated with other building materials. 

A board foot is a unit that’s 12 inches tall by 12 inches wide and 1-inch thick. To determine how much spray foam insulation you need, find the square feet and multiply it by the necessary depth in inches. 

Here’s a look at costs:

• Open-cell polyurethane: $0.45–$0.65 per board foot 

• Closed-cell: $1–$1.55 per board foot

• Plant-based: $1.50–$3.00 per board foot

• Water-based: $0.50–$2.50 per board foot

DIY spray foam insulation kits cost more per board foot, but you’ll typically purchase only enough for one small project at a time. Kits cost around $350 for 200 board feet of insulation and about $800 for 600 board feet. 

Benefits of Spray Foam Insulation

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Thinking about taking on a do-it-yourself project for your home? Spray foam outperforms most other types of home insulation for several reasons.

• Closed-cell foam seals air, eliminating need for additional vapor barrier

• Excellent soundproofing in interior and exterior walls

• Eliminates drafts from outdoors

• Sticks to concrete and other materials, making it great for basement applications

• Doesn’t require fasteners to stay in place

• Won’t settle over time 

• Is mold resistant 

Where to Use Spray Foam Insulation

There are several common types of home insulation. Spray foam insulation can replace and, in almost all cases, exceed the performance of most of them. The exception is radiant barriers or reflective barriers, which work differently from traditional forms. 

In new construction, the builder installs spray foam insulation after framing and before the drywall goes on. Although you can install spray foam insulation into a complete wall, the task isn’t common due to the need to remove much of the drywall before installing the spray material. 

For remodeling or upgrading your insulation, spray foam insulation is an excellent product with a higher R-value, or insulating ability, than most other products. In existing homes, use spray foam in basements and crawl spaces, between floor joists on the rim boards, in attics, or inside walls that are open for remodeling purposes.

Spray foam insulation works well in nearly every project where you’d use more traditional types of insulation.

• Exterior walls: Closed-cell foam seals gaps to eliminate drafts around outlets and switches. 

• Interior walls: Works well as a sound barrier in your home.

• Attic: You can use spray foam insulation in attics as a replacement for blown cellulose insulation.

• Under roof deck: Works in “hot roof” applications where the insulation fills the rafter spaces directly under the roofline.  

• Between floor joists: Use directly against the rim board in the basement or crawl space to replace fiberglass batt or foam board insulation.

• Use in tight spaces: It’s easy to use around plumbing or wires where installing other types of insulation is difficult. 

• Air barrier: You can use it in conjunction with fiberglass batts. 

Where Not to Use Spray Foam Insulation

Because of its expansion rate and ability to impede air and water movement, there are some places where you should not install spray foam insulation. 

• Avoid installing spray foam insulation if the location is wet from water damage or is treated lumber. Allow the wood to dry out before installing.

• Refrain from spray foam insulation into an enclosed space. 

• Keep spray foam insulation away from recessed light cans. It will trap heat from the light, which can cause a fire.

• Don’t use expanding spray foam in crevices near windows or doors. Low-expansion foam from a can is appropriate in those locations.

How to Install DIY Spray Foam Insulation

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Installing DIY spray foam insulation is nearly identical to how the pros do the job, except for the size of the tools. 

Professionals will pull up in a truck containing everything they need, while DIYers will carry a box and a nozzle sprayer around. 

• Prepare the area by taping plastic over windows, doors, and anything else you want to protect. 

• Get everything out of your way for clear and easy access to every place you need to insulate.

• Spray in a picture frame pattern around each stud or joist space to fill any air gaps. 

• Come back and spray on a 1-inch thick layer of foam.

• Allow the first layer to cure and add the second and subsequent layers, called lifts, in the same manner. 

• Cut away excess foam with a foam carving tool and test the depth with a wire or similar object by poking through the material to the material below if necessary. 

DIY Spray Foam Insulation Safety Precautions 

Installing polyurethane spray foam insulation requires taking safety precautions to keep your skin and lungs safe.

You can remove the material from your skin with acetone or mineral spirits in its wet form. However, it's difficult to remove once it's dry, and you’ll likely need to scrape it off. The same is true for getting the stuff on your clothing. Wear full personal protective equipment when handling spray foam insulation. 

• Before starting, you should have a few DIY skills equivalent to spray-painting proficiency and some knowledge of insulation principles, so you know where to put the product. 

• Wear a full protective suit, such as a spray painting suit.

• Put on safety goggles with a strap, so they stay secure while moving around. 

• Use chemical-resistant gloves and tuck them into or tape them to the sleeves of your suit.

• Wear a vapor-blocking respirator.

• Wear work shoes or boots.

Spray Foam Insulation Installation Tips

Although DIY spray foam installation isn’t complicated, it has some peculiarities to keep in mind before and during your project. 

• Set everything you need within easy reach and have a clear path to every place you need to work. Once you start spraying, you can only stop for several seconds before you must replace the spray nozzle tip. 

• You don’t have to hurry but move efficiently at a steady pace. 

• If you don’t have a helper, it’s easier to use two easily movable spray-in foam insulation kits one at a time than carrying one large one. 

• Only apply spray foam insulation if the air, walls, and foam containers' temperatures are above 65 degrees Fahrenheit.

• Lubricate the trigger handle outlet with the petroleum jelly in the kit when replacing the nozzle tip. 

• Only work in a well-ventilated area, or employ a fan or several to move the air out of the space.  

Is DIY Spray Foam Worth It?

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From an energy-saving standpoint, there’s little doubt that using spray foam insulation over other types has advantages. 

Closed-cell versions are highly resistant to heat transfer, with R-values reaching R-7 per inch of thickness. This means it’s almost twice as effective at keeping cold or hot air out as fiberglass or blown-in types. Depending on your monthly energy bill, the investment will pay for itself in short order. 

DIY installation has one glaring drawback in that only limited types of spray foam insulation kits are available to the public. Most bulk spray foam suppliers only sell to professional installation companies.

The installation costs favor hiring a pro to do the work for large jobs. The DIY kits contain far less material for the price. However, the DIY option is cost-effective for small jobs, like insulating rim joists or a crawl space. Also, you won’t have to worry about scheduling an installer, and you’ll avoid possible trip charges for small jobs. 

When to Hire a Professional

If you’re building a new home, performing an extensive remodel, desire a specialty foam, or are replacing much of your home’s insulation, you’ll likely want to find a local spray foam insulation installation company for the work. 

For small projects, such as adding insulation to your basement or crawl space, soundproofing an interior wall, or only insulating an exterior wall or two, it’s time to get your DIY on.