Like all forms of insulation, spray foam is designed to prevent heat from traveling between the interior of your home and the exterior. Most often, this is between a warm home and a cold exterior, although in hot climates it can be a cool interior and warm air outside. Insulation allows you to reduce your home HVAC costs, meaning that the outlay for insulation is returned by reduced utility bills.
Spray foam insulation is insulation that is sprayed as a liquid into cavity spaces within your home. As the spray foam dries, it expands and hardens, providing a rigid layer of insulation that fills all available space. There is a wide variety of spray foams available on the market with slightly different chemical compositions, causing them to act in slightly different ways.
For example, some spray foams dry more slowly and are more dense – this allows them to flow over potential obstacles before expanding. For more information on various types of spray foam insulation, go to our spray foam insulation guide.
Spray foam is an excellent insulating material owing to the fact that it creates a solid block of insulation. In addition to heat, it insulates well against noise and some types are designed to also insulate against water and water vapor.
Spray foam has some of the highest R-values that you can buy commercially, meaning it is an extremely effective solution for some parts of your home. For pricing information on other popular types of home insulation go to our pages on the average cost of fiberglass rolled and batt insulation and the average cost of blown-in insulation.
This guide will walk you through the costs involved in installing spray foam so you can see if it’s the right option for you.
AVERAGE SPRAY FOAM HOME INSULATION
Below is a breakdown of the prices involved in spray foam insulation. As a point to note, because it is unlikely you will be able to install spray foam insulation yourself, we have factored labor costs into this guide. All prices, therefore, include the cost of installation. Although you can install spray foam yourself, you would need to be experienced in doing so.
In addition, the rough labor cost of $50 to $150 per hour would most likely be offset by the cost of hiring the equipment commercially.
THE OVERALL COST
The average cost of installing spray foam in your home is $2,376. This varies based on the following factors:
- Where you are located in the country
- The size of the space being filled
- Any complicating factors on the space’s size, shape, or location
For a 200 square foot wall cavity to be filled with spray foam insulation will cost between $300 and $600 (again, the precise location within the range is determined by the factors above).
A board foot is a useful metric to know when it comes to spray foam installation. One board foot is one square foot of area, with a depth of one inch. This allows for easy comparison between different installation costs.
For example, if you have a square foot of insulation that is two inches thick, that is two board feet. Similarly, two square feet of area with one inch thick is also two board feet. Generally, spray foam insulation costs between $0.44 and $1.50 per board foot.
The primary difference between open-cell and closed-cell insulation is that open-cell insulation tends to be more flexible and more ‘spongy,’ whereas closed-cell is more rigid. It doesn’t block water vapor and has a lower R-value.
Open-cell spray foam will cost between $0.35 and $0.55 per board foot to install.
Closed-cell insulation has a higher R-value, blocks water vapor and will cost between $1.00 and $2.00 per board foot to install. There is an economy of scale involved, so the larger the square footage, the smaller the per square footage cost. For example, to cover a 1,500 square foot space with a one-inch thick layer of closed-cell spray foam insulation, you will pay between $1,500 and $2,250.
The costs are slightly different when it comes to metal buildings because of the way the spray foam ‘takes’ (i.e. how it combines with the surfaces). For a 1,500 square foot metal space, you will pay between $1,600 and $2,400.
As mentioned above, one of the key variables in price is the actual location of the space to be insulated. Different parts of your home require different chemical compositions of foam and have different levels of difficulty to reach.
Below are some examples of different parts of your home and the costs to insulate them with spray foam.
Attics are usually insulated with foam rolls or batts. However, you can supplement this with spray foam insulation. To insulate a typical-sized attic, you can expect to pay around $2,200.
Basement walls usually require expanding foam that has some level of water resistance (because basements are below ground, they are susceptible to moisture and flooding).
The cost of insulating a basement with spray foam is around $2,140.
Like a basement, crawl spaces require special spray foam. Most crawl space insulation projects use polyurethane foam. This is a cheaper material and costs around $80 for a 20 square foot crawl space.
Because hot air rises, a lot of insulation (rightly) focuses on insulating the roof of a house. In addition to insulating the attic, you can insulate the roof to provide a second layer of protection against heat loss.
Roof insulation is usually sprayed between the joists on the roof itself. This usually costs between $1,650 and $2,200.
If you have a garage that you use for storage, or if your garage is connected to your home, you may need to add insulation to ensure that not too much heat is lost. If you want to install the walls of an average-sized 750 square foot garage, it will cost between $200 and $600.
If you are insulating a barn, spray foam is usually the best material to do so because of the way it can endure being exposed to the elements.
For a standard 1,200 square foot pole barn with 12-foot ceilings, you will spend between $740 and $2,540 to insulate.
SIZE IN SQUARE FEET
The cost of materials makes up a significant part of the overall cost of installing spray foam. The below table will give you a general point of reference when it comes to the cost of materials in square feet (of one-inch thickness, or one board foot).
|100||$44 – $150|
|200||$88 – $300|
|300||$132 – $450|
|400||$176 – $600|
|500||$220 – $750|
|1,000||$440 – $1,500|
|1,500||$660 – $2,250|
|2,000||$880 – $3,000|
|2,500||$1,100 – $3,750|
|3,000||$1,320 – $4,500|
*All costs assume a one-inch foam thickness. Multiply price by additional inches as needed for the best estimate.
INJECTION FOAM INSULATION
COSTS BY THICKNESS
In addition to spray foam, there is also the option for injection foam. Injection foam can be inserted into any closed cavity (such as a wall cavity) and requires little or no damage to objects like drywall (since you only need a small insertion point). This reduces the cost of repair and replacement. In addition, injection foam is pre-mixed by the contractor and then injected on-site, further reducing labor costs.
The determinant of the cost when it comes to injection is the thickness of the foam (or the thickness of the cavity it is being inserted into). The table below gives an outline of these figures.
|1″||$0.44 – $1.50|
|2″||$0.88 – $3.00|
|3″||$1.32 – $4.50|
|5,000||$1.76 – $6.00|
As with spray foam, it is extremely unlikely you will be able to insert injection foam yourself without any professional training. Therefore, you must add labor costs onto these prices.
The real advantage of this form of insulation is the fact that it is non-invasive in your day-to-day life, as contractors drill a series of small holes and then insert the insulation that way.
Spray foam may involve you having to clear a section of the house, place down sheeting, and avoid it while it dries. Therefore, you can factor in the potential lost income if you have to be at home during the process of installing spray foam.
Spray foam can be the most expensive form of insulation, particularly in large quantities.
However, it also has some of the highest R-values that you can buy for your home. The money you spend, therefore, is extremely efficient when it comes to actually insulating your property.
Because of the ease of installation (for a professional) of spray foam, the labor costs are lower than a professional batt installation.
In addition, you get ancillary benefits such as noise reduction and – in some cases – reduction in dampness.
If you are going to insulate your wall cavities or basement, spray foam is almost certainly the best long-term solution. You need to factor longevity into any calculations you make, as having to replace insulation after 10-20 years will require a whole new series of spending. Given this, spray foam insulation becomes an increasingly better investment the more you play with the numbers.