How Much Does Rigid Foam Insulation Installation Cost?

Typical Range:

$2,500 - $7,500

Find out how much your project will cost.

Cost data is based on research by HomeAdvisor.

Updated January 24, 2022

Written by HomeAdvisor.

It costs between $2,500 and $7,500 to install rigid foam insulation in your home. Most homeowners pay around $5,000 to install foam board insulation in their attic. You may also consider installing rigid foam insulation, or foam board, in your garage to help increase your home’s efficiency.

Average Cost to Install Rigid Foam Insulation

Average Cost $5,000
High Cost $7,500
Low Cost $2,500

Rigid Foam Insulation Prices

It costs $0.25 to $1.40 per square foot for the foam board itself, excluding the cost of labor. Rigid foam insulation is usually sold in 8-by-4 foot boards. Your actual cost will vary based on the thickness of the board, whether it's faced or unfaced, and its R-value.

Rigid Foam Insulation Costs

A local insulation contractor will charge $0.25 to $0.50 per square foot. Therefore, you'll pay $25 to $50 per 100 square feet for installation costs alone. The more complicated the job, the higher the price. For example, removing old insulation or repairing insect or wildlife damage will be more costly. 

Rigid Foam Insulation Cost By Room Size

Given that insulation costs are determined by the square foot, here are a few calculations based on common space sizes.

Square Footage Cost Range (All-In) Average Cost (All-In)
500 sq. ft. $500 – $3,500 $2,000
750 sq. ft. $750 – $5,250 $3,000
1,000 sq. ft. $1,000 – $7,000 $4,000
1200 sq. ft. $1,200 – $8,400 $4,800
1,500 sq. ft. $1,500 – $10,500 $6,000

Rigid Foam Insulation Cost by Area in Home

How much you'll pay for rigid foam insulation installation depends on what part of your home you want to insulate. Adding foam board to the garage door, for example, costs less than insulating the attic.

Home Space Cost Range (All-In) Average Cost (All-In)
Garage $0.50 – $1.25 per sq. ft. $0.90 per sq. ft.
Crawl Space or Floor $1 – $5 per sq. ft. $3 per sq. ft.
Basement $1.50 – $2.50 per sq. ft $2.50 per sq. ft.
Attic $2.50 – $7.50 per sq. ft. $5 per sq. ft.
Wall $1 – 4 per sq. ft. $2.50 per sq. ft.
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Rigid Foam Insulation Cost By Type of Foam

There are several different types of foam used in rigid board insulation, which will directly impact cost. The table below lists foam insulation prices per board foot. A board foot is one square foot that's one inch thick.

Type Range Per Board Foot Average Cost Per Board Foot
Polyiso $0.40 – $0.60 $0.50
EPS $0.25 – $0.35 $0.30
XPS $0.40 – $0.50 $0.45
SIPs $7 – $12 $9.50

Polyiso

Polyisocyanurate, or polyiso insulation, costs an average of $0.50 per board foot. It's a common choice for flat roof projects and is available in boards between 1 and 4 inches thick. Polyiso foam boards have an R-value of around 8 per inch. Therefore, a 4-inch thick board will have a maximum R-value of 32 and cost $1.60 to $2.40 per square foot

Polyiso insulation boards, unlike most other types, do not perform well in very cold conditions. If the temperature dips below 59 degrees Fahrenheit, the foam begins to deteriorate and has a noticeable drop in performance.

Expanded Polystyrene (EPS)

Expanded polystyrene insulation, or EPS, costs an average of $0.30 per board foot. It has an R-value of 4 per inch, and a maximum thickness of 12 inches. This means that the maximum R-value is 48, which would cost $3 to $4.20 per square foot. EPS has a closed-cell structure and is breathable, so it is less likely to absorb and retain water than Polyiso. This relatively cheap insulation board has a high R-value-to-cost ratio, making it a popular choice.

Extruded Polystyrene (XPS)

Extruded polystyrene, or XPS, costs $0.45 per board foot. It's also known as Styrofoam and is a common rigid board insulation choice, particularly for those looking to save space. It has an R-value of 5 per inch and a maximum thickness of 4 inches. You’d pay $1.60 to $2 per square foot for a maximum R-value of 20

It’s not advisable to use below-grade XPS foam because it “off-gasses,” which occurs when a material releases volatile organic compounds (VOCs) into the air. When inhaled in spaces with little ventilation like a basement, these chemicals pose a health risk. The health risks, plus the fact that manufacturers use hydrofluorocarbons to produce XPS, make this rigid foam less Earth-friendly than other rigid foam board types. The hydrofluorocarbon molecules (HFCs) have a global warming potential (GWP) 1,430 times greater than carbon molecules.

Structural Insulated Panel (SIPs)

Structural insulated panels (SIPs) cost around $9.50 per square foot (not board foot). SIP boards come in a complete unit that consists of a 4-inch thick piece of rigid foam board sandwiched between two plywood or oriented standard board (OSB) sheets. These rigid foam insulation boards are weight-bearing and can replace traditional stick framing for walls and roofs, making them popular for new builds.

DIY vs. Hiring an Insulation Pro

While installing rigid foam insulation yourself is possible, you'll most likely get better results by hiring a pro. Rigid foam insulation requires careful installation for maximum efficiency. A pro can address the more challenging aspects, like insulating around pipes, wiring, and electrical outlets. If you DIY the installation, you risk leaving gaps around pipes and outlets, resulting in thermal bridges. This will significantly reduce your home’s R-value and efficiency.

FAQs About Rigid Foam Insulation

Is rigid foam insulation good for walls?

With the proper installation, rigid foam is a good choice for walls, particularly in new builds. You can also use it in floors and ceilings.

Is rigid foam a good insulator?

Yes, rigid foam is a good insulator. R-values vary from 4 to 8 per inch of thickness. The cost also increases as you scale the R-value and thickness of the insulation.

Is rigid foam insulation expensive?

Rigid foam insulation is comparatively expensive when it comes to upfront costs. However, those costs balance out long-term considering how effective it is at reducing your home’s energy waste. Plus, rigid has a longer lifespan, with some types lasting 100 years or more. You’ll rarely need to replace it.

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