# Closed Cell Spray Foam Insulation Cost

March 1st, 2024 | 5 min read

You want spray foam insulation, but you’re worried about the cost. You’ve heard that spray foam is an expensive insulation product. How much does closed cell spray foam cost specifically?

South Central Services has insulated hundreds of homes with spray foam insulation. Our crew works with both closed cell and open cell spray foam. We regularly meet with customers to evaluate their projects and create personalized quotes. We believe anyone should be able to roughly estimate their project costs, even without speaking directly with a professional contractor.

By the end of this article, you will know:

- The cost per square foot of closed cell spray foam
- The cost per board foot of closed cell spray foam
- Sample estimates for closed cell spray foam insulation

## How Much Does Closed Cell Spray Foam Cost Per Square Foot?

The cost per square foot of spray foam insulation depends on the depth of insulation being installed. In Pennsylvania, a wall application only needs 2 to 4 inches of closed cell spray foam. In contrast, a roof application could have up to 6 inches of closed cell installed. The cost per square foot won’t be the same for a wall compared to a roof.

To combat this inconsistency, contractors use a measurement called board feet. Board foot rates can be applied across applications. Rather than having a different rate for every type of project, professional spray foam installers can easily calculate a cost regardless of the application type. The diagram below shows the difference between a board foot and a square foot.

To calculate board feet from square footage, multiply your square footage by the insulation depth you need installed.

Let’s return to our exterior wall as an example. If you want to insulate a 10 foot by 10 foot wall, you have 100 square feet that need to be insulated. Exterior walls in our climate zone need between 2 and 4 inches of closed cell spray foam to comply with building codes. The board feet of that wall would be a minimum of 200 board feet.

Because cost per square foot is unique to every application, we will give cost per board foot.

Closed cell spray foam insulation costs between $1.15 and $1.75 per board foot. The average cost is approximately $1.45 per board foot.

### Do I Need To Calculate Cost Per Board Foot?

As a homeowner, you do not need to use the cost per board foot in your calculations. However, it will serve you well to understand the concept of board feet as you do additional research into spray foam insulation.

For example, DIY spray foam kits are measured in board feet, not square feet. It will also simplify calculations if you only need to remember one range of rates.

## Sample Closed Cell Spray Foam Estimates

Closed cell spray foam insulation is one of the most versatile insulation products. Compared to its counterpart, open cell spray foam, closed cell can be used in nearly twice as many applications.

In the following sections, we will give examples of how to calculate estimates for closed cell spray foam. Specifically, we will cover:

- Exterior walls
- Basement walls
- Basement ceilings
- Crawl spaces
- Attic floors
- Attic ceilings

Each example will include subjective rates for the cost per square foot. The most accurate way to calculate an estimate is with board feet.

Let’s examine these in more detail.

### Estimate For Closed Cell In An Exterior Wall

In an exterior wall, the cost per square foot would be between $2.90 and $5.80, with a maximum cost per square foot of $7.00. We can calculate this rate based on the board foot rate and the depth of insulation needed in exterior walls.

- Depth of closed cell spray foam for exterior walls: 2 to 4 inches
- Rate of closed cell spray foam per board foot: $1.15 to $1.75

For the following example, we calculated two costs per square foot. Using the average amount of closed cell insulation needed in exterior walls, we calculated at the lowest and highest end of our cost per board foot range.

The cost to insulate this exterior wall with closed cell spray foam can range anywhere from $518 to $788. The price could also be lower or higher with more or less closed cell spray foam.

### Estimate For Closed Cell In A Basement Wall

In a basement wall, the cost per square foot would be between $2.90 and $4.35, with a maximum cost per square foot of $5.25. We can calculate this rate based on the board foot rate and the insulation depth needed in basement walls.

- Depth of closed cell spray foam for basement walls: 2 to 3 inches
- Rate of closed cell spray foam per board foot: $1.15 to $1.75

For the following example, we calculated two costs per square foot. Using the greatest amount of insulation needed in basement walls, we calculated at the lowest and highest end of our cost per board foot range.

The cost to insulate these basement walls with closed cell spray foam can range anywhere from $1,656 to $2,520.

### Estimate For Closed Cell In A Basement Ceiling

In a basement ceiling, the cost per square foot would be between $2.90 and $5.80, with a maximum cost per square foot of $7.00. We can calculate this rate based on the board foot rate and the depth of insulation needed in basement walls.

- Depth of closed cell spray foam for basement ceilings: 2 to 4 inches
- Rate of closed cell spray foam per board foot: $1.15 to $1.75

For the following example, we calculated two costs per square foot. Using the greatest amount of insulation needed in basement walls, we calculated at the lowest and highest end of our cost per board foot range.

The cost to insulate this basement ceiling with closed cell spray foam can range anywhere from $743 to $1,134.

For a basement ceiling, you can also use open cell spray foam insulation. Open cell is a cheaper option for this application. Open cell offers better sound control if you’re interested in sound control between your basement and living space.

### Estimate For Closed Cell In A Crawl Space

Closed cell spray foam is one of several components in crawl space encapsulation. When we insulate a crawl space, we also install a vapor barrier using plastic sheathing. The encapsulation method has countless benefits but is also challenging to estimate online.

Every crawl space is different and there are numerous factors that influence the cost of encapsulation. The lowest cost to encapsulate is $4 per square foot, while the highest cost is $8 per square foot.

In the following example, the cost of closed cell spray foam in a crawl space is calculated at the lowest, average, and highest costs.

Depending on the complexity of this crawl space, the price can range from $3,500 to $7,000.

### Estimate For Closed Cell In An Attic Floor

In an attic floor, the closed cell cost per square foot would be between $4.35 and $8.70, with a maximum cost per square foot of $10.50. We can calculate this rate based on the board foot rate and the insulation depth needed in basement walls.

- Depth of closed cell spray foam for attic floors: 3 to 6 inches
- Rate of closed cell spray foam per board foot: $1.15 to $1.75

For the following example, we calculated two costs per square foot. Using the average amount of closed cell insulation needed in an attic floor, we calculated at the lowest and highest end of our cost per board foot range.

The cost to insulate this attic floor with closed cell spray foam can range anywhere from $3,450 to $5,250.

### Estimate For Closed Cell In An Attic Ceiling

In an attic ceiling, the closed cell cost per square foot would be between $4.35 and $8.70, with a maximum cost per square foot of $10.50. We can calculate this rate based on the board foot rate and the insulation depth needed in basement walls.

- Depth of closed cell spray foam for attic ceilings: 3 to 6 inches
- Rate of closed cell spray foam per board foot: $1.15 to $1.75

For the following example, the calculated costs per square foot are the same as for attic floors. Using the average amount of insulation needed in an attic ceiling, we calculated at the lowest and highest end of our cost per board foot range.

The cost to insulate this attic ceiling with closed cell spray foam can range anywhere from $5,865 to $8,925.

Notice that the cost to insulate the attic ceiling is higher than the attic floor, due to the higher amount of square footage in an identical attic.

## The Bottom Line About Closed Cell Spray Foam Costs

Of the two types of spray foam insulation, closed cell spray foam is more expensive. Closed cell spray foam is also quite versatile and can be used in any area of the home. The cost per board foot for closed cell ranges from $1.15 to $1.75. The cost per square foot varies depending on the area of the home, because different applications need different amounts of insulation.

The greater the square footage of your project, the more expensive it can be. Additionally, attic applications generally require the most closed cell spray foam and are more expensive.

Now that you understand how much closed cell spray foam costs, your next step is to:

Alexis has been fascinated by spray foam insulation since 2018. When she isn’t thinking about insulation, Alexis is geeking out over storytelling and spreadsheets.

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