Spray foam insulation in Utah costs $0.45 to $0.75 per board foot for open cell and $1.00 to $1.70 per board foot for closed cell, installed. A typical Utah County attic project runs $1,500 to $7,000 depending on approach, and rim joists run $1,000 to $2,500. Utah Valley Foam is an independent insulation referral service covering Utah County, and this page shows how those numbers turn into a price for your specific house.
What a Board Foot Is, and Why Every Quote Uses It
A board foot is one square foot of area at one inch of depth. It is the unit spray foam is priced in, because foam is sold by volume rather than by area.
The conversion you need is simple:
Square feet x inches of depth = board feet. Board feet x rate = your price.
So 1,000 square feet at 3 inches of closed cell is 3,000 board feet, which at $1.00 to $1.70 comes to $3,000 to $5,100. Depth is the variable that moves the number most, and it is the one homeowners never think to ask about.
Spray Foam Prices in Utah
| Item | Price | Unit |
|---|---|---|
| Open cell spray foam | $0.45 to $0.75 | per board foot, installed |
| Closed cell spray foam | $1.00 to $1.70 | per board foot, installed |
| Attic project | $1,500 to $7,000 | per project, approach dependent |
| Rim joists | $1,000 to $2,500 | per project |
| Old insulation removal | $1.00 to $2.00 | per square foot |
Why the Attic Range Is So Wide
Run the board foot maths on an attic and something looks wrong. Utah’s code calls for R-49 in the ceiling, which is 13 to 14 inches of open cell. Across a 1,000 square foot attic floor that is 13,000 to 14,000 board feet, or $5,850 to $10,500. That is well above the $1,500 to $5,000 that real attic floor jobs actually cost.
The discrepancy is real, and it is the most useful thing on this page: filling an attic floor with full-depth foam is almost never the right specification. Foam’s advantage is the air seal, and you get essentially all of that from the first two or three inches. Paying foam prices for inches four through fourteen buys you R-value you could have bought far cheaper.
So there are three sensible approaches, and they cost very different amounts. The ceiling plane below is the flat surface between your top floor and the attic, in other words the back of your ceiling drywall:
| Approach | What gets installed | Typical cost | Best for |
|---|---|---|---|
| Air seal and top up | 2 to 3 inches of foam on the ceiling plane, then blown insulation to R-49 | $1,500 to $5,000 | Most Utah County retrofits |
| Unvented roof deck | About 7 inches of open cell against the roof deck, to R-26 | $3,000 to $7,000 | Homes with HVAC or ducts in the attic |
| Full-depth foam on the floor | 13 to 14 inches of open cell to R-49 | Higher than both, rarely justified | Almost nobody |
If you are comparing quotes and one is half the price of another, this is usually why. They are not quoting the same job. Ask each contractor what depth of what product, on which surface. The full code breakdown is on our Utah insulation code requirements page.
What Drives Your Price Up or Down
- Depth specified. The single biggest factor. Double the inches, double the material.
- Open cell or closed cell. Closed cell costs roughly twice as much per board foot, and reaches a given R-value in about half the depth. Where space is not tight, open cell gives more R per dollar.
- Removal of old material. Rodent damage, water staining, or mould means the old insulation comes out first, at $1.00 to $2.00 per square foot on its own line. See insulation removal.
- Access. A walk-in attic with a floored deck is quick. A 30 inch crawl space, or an attic reached through a bedroom cupboard hatch, is not.
- Prep and masking. Foam sticks to everything. Finished spaces need far more protection than bare framing.
- Complexity. Knee walls, dormers, cathedral sections, and can lights all slow the job down.
- Minimum job size. Mobilising a rig has a fixed cost, so very small jobs carry a minimum charge in this trade.
Is Spray Foam Worth It Compared to Fiberglass?
Per unit of R-value, fiberglass wins on price every time. That comparison misses the point, because R-value only measures conduction. It says nothing about air moving through the assembly, and fiberglass does not stop air at all.
The EPA estimates that air sealing and insulating attics, crawl spaces, and rim joists saves an average homeowner about 15 percent on heating and cooling. As a worked example: if your heating and cooling costs $150 a month, 15 percent is roughly $270 a year. Put your own numbers in, because that figure moves with your fuel type, your current insulation level, and how leaky the house is to begin with.
Honest summary: if the house is leaky and under insulated, which describes most Utah County homes built before 2010, foam is usually worth it. If the ceiling plane is already sealed and you simply want more depth, blown fiberglass is the cheaper answer and we will tell you so. The full comparison is on spray foam vs fiberglass.
What You Can Claim Back
Not the federal tax credit. It is gone. The 25C Energy Efficient Home Improvement Credit expired on December 31, 2025, so insulation installed in 2026 earns no federal credit, whatever older articles still say.
What remains in Utah County is the Rocky Mountain Power wattsmart rebate, worth $0.10 per square foot on attic insulation and more on walls and floors, subject to eligibility rules. Full detail, including whether your home qualifies, is on our Utah insulation rebates page.
How to Read a Spray Foam Quote
A quote you can actually compare states all five of these. If any are missing, ask:
- Product. Open cell or closed cell, named explicitly.
- Depth. In inches, per surface. “Attic” is not a depth.
- Surface. Attic floor or roof deck. They are different jobs at different prices.
- Target R-value. What the finished assembly is meant to achieve.
- Removal, separately. Bundled into one total, you cannot tell what you are paying for.
Spray Foam Cost FAQ
How much does spray foam insulation cost in Utah?
Open cell runs $0.45 to $0.75 per board foot installed and closed cell $1.00 to $1.70. A board foot is one square foot at one inch deep, so a 1,000 square foot area at 3 inches of closed cell works out to roughly $3,000 to $5,100.
How much does it cost to spray foam an attic in Utah County?
$1,500 to $7,000, depending on the approach. Air sealing the ceiling plane with foam and topping up with blown insulation to R-49 runs $1,500 to $5,000. Foaming the roof deck to create an unvented attic runs $3,000 to $7,000.
Why are spray foam quotes so different from each other?
Almost always because they specify different depths, different products, or a different surface. A quote for 2 inches on the attic floor and a quote for 7 inches on the roof deck are not the same job. Compare depth and product, not the total.
Is closed cell worth double the price of open cell?
Below grade, against concrete, in tight cavities, or anywhere moisture is a factor, yes, and it is the only foam we recommend there. In an open attic with room to work, open cell delivers more R-value per dollar and is usually the better buy.
Is there still a tax credit for insulation?
No federal one. The 25C credit expired December 31, 2025. Rocky Mountain Power’s wattsmart rebate is what remains for Utah County homeowners, at $0.10 per square foot on attic insulation subject to eligibility rules.
Does the price include removing my old insulation?
Not in our quotes. Removal runs $1.00 to $2.00 per square foot and we put it on its own line so you can see both numbers. Clean, dry insulation can often stay, in which case there is nothing to remove and nothing to pay.
For a ballpark on your specific house, describe the project on the phone and you will have a number before the call ends. Call (801) 691-7136, anywhere in Utah County, or read the detail on attic and crawl space projects.