Spray Foam Insulation Cost (2026): DIY Kits vs Hiring a Pro
Updated
Verdict Hire a pro · 1,500 sq ft attic roof deck
Installing spray foam insulation costs $8,215–$8,495 to do yourself and $5,000–$11,000 to hire a pro, per 1,500 sq ft attic (roof deck, R-21 to R-30).
Hire a spray foam contractor for attics, garages and outbuildings. DIY kits cost $1.30–$2.00 a board foot — as much as a pro's installed price — so a 1,500 sq ft attic done from kits runs $8,215–$8,495 against a $7,500 quote, a pole barn is a wash, and a two-car garage saves about $500 for 8–14 hours in a respirator. Do it yourself only where a pro's minimum charge is the whole price: rim joists, a shed, or a few hundred board feet of gaps, where a $400 kit and safety gear come to about $570 against a $900 minimum.
- DIY Rim joists and small gaps
- Hire Two-car garage, walls and ceiling
- Hire 1,500 sq ft attic roof deck
- Hire 30×40 pole barn or shop
- DIY cost
- $8,215–$8,495
- 14–24 hours of your time · 1,500 sq ft attic roof deck
- Pro cost
- $5,000–$11,000
- typical $7,500 · per 1,500 sq ft attic (roof deck, R-21 to R-30)
- Typical savings
- —
- DIY costs more
- Pros charge by the board foot: $0.60–$1.20 for open-cell, $1.30–$2.50 for closed-cell, installed. That's about $900 for rim joists (a minimum-charge job), $3,500 for a two-car garage, $7,500 for a 1,500 sq ft attic roof deck and $9,500 for a 30×40 pole barn.
- DIY kits cost $1.30–$2.00 a board foot — the same as a pro's installed price — because contractors buy foam by the drum. An attic done from kits is $8,215–$8,495 against a $7,500 quote; the pro is cheaper.
- DIY wins only where the pro's minimum charge is most of the price. Rim joists: a $400 kit plus respirator and suit is $515–$625 against $900, for 3–5 hours. A two-car garage saves about $500, before the drywall code requires over it.
- Foam left exposed in an attic needs an ignition-barrier coating; foam in a garage or shop needs drywall. Kit math never includes it, and it's $750–$5,000.
DIY vs pro at a glance
| DIY | Pro | |
|---|---|---|
| Cost per job (1,500 sq ft attic roof deck) | $8,215–$8,495 | $5,000–$11,000 |
| Cost range (all sizes) | $515–$9,415 | $600–$13,000 |
| Your time | 14–24 hours | Getting quotes, ~1–2 hours |
| Skill needed | Intermediate | None |
| Injury / damage risk | Medium | Carried by the contractor (if insured) |
| Equipment you'd need to buy or rent | Full-face respirator with organic-vapor cartridges, Disposable coveralls, nitrile gloves, goggles, Masking plastic, tape, rags and acetone for cleanup | None |
| Permit | Sometimes — you apply | Sometimes — usually pulled by the pro |
| Best when | The job is a few hundred board feet or less — rim joists, a shed, a van, gaps around a foundation — and a pro's minimum charge is most of the quote | It's an attic roof deck, a whole garage, or a barn — thousands of board feet where a contractor's drum pricing beats kit pricing |
What pros charge for installing spray foam insulation
| Job size | Low | Typical | High |
|---|---|---|---|
| Rim joists and small gaps — about 200 board feet: the rim joist of a 1,500 sq ft basement, or a small shed, at 2 in closed-cell | $600 | $900 | $1,500 |
| Two-car garage, walls and ceiling — about 1,000 sq ft of framed surface at 2 in closed-cell (2,000 board feet) | $2,600 | $3,500 | $5,000 |
| 1,500 sq ft attic roof deck — unvented attic: 7 in open-cell or 3.5 in closed-cell on the underside of the roof (5,000–10,000 board feet) | $5,000 | $7,500 | $11,000 |
| 30×40 pole barn or shop — about 3,000 sq ft of walls and roof at 2 in closed-cell (6,000 board feet) | $7,000 | $9,500 | $13,000 |
What moves the price
- Open-cell or closed-cell
- Open-cell foam is $0.60–$1.20 per board foot installed, R-3.5 per inch, soft and vapor-open; closed-cell is $1.30–$2.50, R-6 to R-7 per inch, rigid, a vapor retarder and a structural stiffener. Closed-cell costs more per board foot but needs half the thickness for the same R-value, so the gap on a finished job is smaller than the per-foot prices suggest.
- Thickness and target R-value
- Price is per board foot — one square foot at one inch — so doubling the depth doubles the material. Code minimums (R-30 to R-49 for attics, R-13 to R-21 for walls, depending on climate zone) set the depth; a contractor who quotes '2 inches' for an attic roof deck is quoting R-12 open-cell, well short of code.
- Area and access
- Big, open, framed surfaces — a pole barn, a new-construction wall — spray fast and price low per foot. An attic with 3 feet of clearance, trusses every 24 inches and a hatch to feed the hose through is slow, hot work priced accordingly. Existing finished walls can't be sprayed at all; that's injection foam, a different product.
- Minimum charge
- Rig setup, the truck, the crew and purging the gun cost the same for 200 board feet as for 2,000. Most contractors have a $600–$1,500 minimum, which is why rim joists and small jobs cost $3–$5 a board foot and why they're the one place a DIY kit wins.
- Prep and removal
- Old fiberglass or cellulose has to come out before foam goes on a roof deck: $1–$2 per square foot. Wiring, recessed lights, can lights, vents and anything else in the cavity has to be masked, rated or moved. A clean framed cavity is the cheapest thing to spray.
- Code coverage
- Foam in an attic or crawl space that's only entered for service needs an ignition-barrier coating ($0.50–$1.00 per sq ft); foam in any occupied or garage space needs a thermal barrier, usually 1/2-inch drywall. Rim joists under 3.25 inches are exempt. A quote that leaves this out isn't complete.
- Region and season
- Prices run 20–40% above the national typical on the coasts and below it in the Midwest and South. Foam cures badly on cold substrates, so winter jobs in the north may need heaters or wait for a warm day.
Common add-ons
| Add-on | Typical cost |
|---|---|
| Remove old attic insulation (1,500 sq ft) | $600–$2,500 |
| Ignition-barrier coating over exposed foam | $750–$2,000 |
| Thermal barrier (1/2 in drywall) in a garage or shop | $1,500–$5,000 |
| Upgrade an attic from open-cell to closed-cell | $1,500–$5,000 |
| Seal attic vents and add rim joist foam to a roof-deck job | $300–$1,200 |
| Combustion-safety test and ventilation for a newly sealed attic | $300–$1,500 |
| Permit and inspection where required | $0–$250 |
What it costs to do it yourself
Rim joists and small gaps: $515–$625 and 3–5 hours
| Item | Cost | Note |
|---|---|---|
| Full-face respirator with organic-vapor cartridges | $60 | Purchase · not a dust mask; isocyanate vapor causes permanent asthma and sensitization |
| Disposable coveralls, nitrile gloves, goggles | $30 | Purchase |
| Masking plastic, tape, rags and acetone for cleanup | $25 | Purchase |
| Work lights, extension cord, fan for ventilation | $60 | Purchase · most homeowners already own this |
| Utility knife and handsaw for trimming overspray | $20 | Purchase · most homeowners already own this |
| Ladder | $120 | Purchase · most homeowners already own this |
| Two-part closed-cell foam kit(s), with gun, hoses and tips | $400 | a 200 board-foot kit is about $400 ($2.00/bf); 600 board-foot kits are $700–$1,000 ($1.30–$1.60/bf). Real yield is 70–85% of the box rating |
| Disposal | $0–$10 | Dump fees, haul-away or bagging |
| Permit | $0–$100 | rarely needed for rim joists or an outbuilding; some states and cities require a permit and energy-code inspection for attic or wall insulation, and converting a vented attic to a sealed one may need mechanical-ventilation sign-off |
| Total (own common tools) | $515–$625 | typical $570 |
| Total (own nothing) | $715–$825 | buying every tool listed |
Two-car garage, walls and ceiling: $2,915–$3,085 and 8–14 hours
| Item | Cost | Note |
|---|---|---|
| Full-face respirator with organic-vapor cartridges | $60 | Purchase · not a dust mask; isocyanate vapor causes permanent asthma and sensitization |
| Disposable coveralls, nitrile gloves, goggles | $30 | Purchase |
| Masking plastic, tape, rags and acetone for cleanup | $25 | Purchase |
| Work lights, extension cord, fan for ventilation | $60 | Purchase · most homeowners already own this |
| Utility knife and handsaw for trimming overspray | $20 | Purchase · most homeowners already own this |
| Ladder | $120 | Purchase · most homeowners already own this |
| Two-part closed-cell foam kit(s), with gun, hoses and tips | $2,800 | a 200 board-foot kit is about $400 ($2.00/bf); 600 board-foot kits are $700–$1,000 ($1.30–$1.60/bf). Real yield is 70–85% of the box rating |
| Disposal | $0–$70 | Dump fees, haul-away or bagging |
| Permit | $0–$100 | rarely needed for rim joists or an outbuilding; some states and cities require a permit and energy-code inspection for attic or wall insulation, and converting a vented attic to a sealed one may need mechanical-ventilation sign-off |
| Total (own common tools) | $2,915–$3,085 | typical $3,000 |
| Total (own nothing) | $3,115–$3,285 | buying every tool listed |
1,500 sq ft attic roof deck: $8,215–$8,495 and 14–24 hours
| Item | Cost | Note |
|---|---|---|
| Full-face respirator with organic-vapor cartridges | $60 | Purchase · not a dust mask; isocyanate vapor causes permanent asthma and sensitization |
| Disposable coveralls, nitrile gloves, goggles | $30 | Purchase |
| Masking plastic, tape, rags and acetone for cleanup | $25 | Purchase |
| Work lights, extension cord, fan for ventilation | $60 | Purchase · most homeowners already own this |
| Utility knife and handsaw for trimming overspray | $20 | Purchase · most homeowners already own this |
| Ladder | $120 | Purchase · most homeowners already own this |
| Two-part closed-cell foam kit(s), with gun, hoses and tips | $7,200 | a 200 board-foot kit is about $400 ($2.00/bf); 600 board-foot kits are $700–$1,000 ($1.30–$1.60/bf). Real yield is 70–85% of the box rating |
| Ignition-barrier (intumescent) coating | $900 | $0.50–$1.00 per sq ft of foam; required over foam left exposed in an attic or shop |
| Disposal | $0–$180 | Dump fees, haul-away or bagging |
| Permit | $0–$100 | rarely needed for rim joists or an outbuilding; some states and cities require a permit and energy-code inspection for attic or wall insulation, and converting a vented attic to a sealed one may need mechanical-ventilation sign-off |
| Total (own common tools) | $8,215–$8,495 | typical $8,355 |
| Total (own nothing) | $8,415–$8,695 | buying every tool listed |
30×40 pole barn or shop: $9,115–$9,415 and 20–35 hours
| Item | Cost | Note |
|---|---|---|
| Full-face respirator with organic-vapor cartridges | $60 | Purchase · not a dust mask; isocyanate vapor causes permanent asthma and sensitization |
| Disposable coveralls, nitrile gloves, goggles | $30 | Purchase |
| Masking plastic, tape, rags and acetone for cleanup | $25 | Purchase |
| Work lights, extension cord, fan for ventilation | $60 | Purchase · most homeowners already own this |
| Utility knife and handsaw for trimming overspray | $20 | Purchase · most homeowners already own this |
| Ladder | $120 | Purchase · most homeowners already own this |
| Two-part closed-cell foam kit(s), with gun, hoses and tips | $8,000 | a 200 board-foot kit is about $400 ($2.00/bf); 600 board-foot kits are $700–$1,000 ($1.30–$1.60/bf). Real yield is 70–85% of the box rating |
| Ignition-barrier (intumescent) coating | $1,000 | $0.50–$1.00 per sq ft of foam; required over foam left exposed in an attic or shop |
| Disposal | $0–$200 | Dump fees, haul-away or bagging |
| Permit | $0–$100 | rarely needed for rim joists or an outbuilding; some states and cities require a permit and energy-code inspection for attic or wall insulation, and converting a vented attic to a sealed one may need mechanical-ventilation sign-off |
| Total (own common tools) | $9,115–$9,415 | typical $9,265 |
| Total (own nothing) | $9,315–$9,615 | buying every tool listed |
Hidden costs of DIY
- Kits cost what a pro charges
- A DIY kit is $1.30–$2.00 per board foot before waste; a contractor's installed closed-cell price is $1.30–$2.50. The contractor buys foam in 55-gallon drums at a fraction of kit prices, so their labor is largely paid for by the material discount. On anything bigger than a few hundred board feet you're paying pro prices to do the work yourself.
- The box yield is optimistic
- Rated yield assumes tanks at 75–85°F, a warm substrate, a fresh tip and a perfect 1-inch pass. Cold tanks, a cold wall, a pause that lets the tip clog, or spraying too thick cuts yield to 70–85%. Budget an extra kit, and keep the tanks in a heated room or on a heating blanket the day before.
- Respirator or nothing
- Isocyanates in the A-side are a leading cause of occupational asthma, and sensitization is permanent. A full-face respirator with organic-vapor cartridges, coveralls and gloves are the minimum; everyone else, and pets, out of the building until it has cured and aired for 24 hours or more.
- Overspray is permanent
- Foam bonds to windows, wiring, ductwork, the car in the garage and the neighbor's fence. It doesn't come off. Masking takes longer than spraying, and a pro's day includes it.
- Code coverage after the fact
- Exposed foam in an attic needs an ignition-barrier coating; in a garage or shop it needs drywall. That's $750–$5,000 the kit math doesn't include, and an inspector or a buyer's home inspector will ask.
- A sealed attic changes the house
- Foaming the roof deck brings the attic inside the thermal envelope. Furnaces and water heaters up there need combustion air, the HVAC may need a supply register, and existing roof vents have to be sealed. A contractor plans for this; a kit doesn't.
When to DIY and when to hire
DIY makes sense when
- The job is a few hundred board feet or less — rim joists, a shed, a van, gaps around a foundation — and a pro's minimum charge is most of the quote
- The surface is a clean framed cavity you can reach standing up, with nothing to mask but a floor
- You'll wear a full-face respirator with organic-vapor cartridges, and everyone else can stay out for a day
- Nothing you spray will be left exposed in an attic, garage or occupied space — or you've priced the ignition barrier or drywall on top
Hire a pro when
- It's an attic roof deck, a whole garage, or a barn — thousands of board feet where a contractor's drum pricing beats kit pricing
- You need a code R-value (R-30+ in an attic), which takes more foam than kits deliver economically
- Old insulation has to come out, or there's wiring, recessed lighting, ducts or a furnace in the space
- You're converting a vented attic to a sealed one and need the ventilation and combustion-safety side handled
Why kits don’t save what you’d expect
Spray foam is a two-part chemical — an A-side of isocyanate and a B-side of polyol — that a contractor buys in 55-gallon drum sets and sprays through a heated rig from a truck. Bought that way, the material is a fraction of a dollar per board foot, and the price you’re quoted is mostly labor, the rig and the overhead of a crew that does this every day.
A DIY kit is the same chemistry in two disposable tanks with a hose and a gun. Packaged that way, it costs $1.30–$2.00 per board foot before waste — the same as a contractor’s installed price for closed-cell foam. That single fact drives everything in the cost tables below. On a 1,500 sq ft attic, kits come to $8,215–$8,495 while a typical quote is $7,500: the pro is cheaper, and the pro also handles removing the old insulation, masking the wiring and can lights, sealing the roof vents and the combustion-safety side of a newly sealed attic. On a pole barn the two are within a few hundred dollars. On a two-car garage you keep about $500 for a day of hot, careful work in a full-face respirator.
The exception is small jobs. A contractor’s minimum charge — $600–$1,500 to bring the truck, set up and purge the gun — is the whole price on rim joists, a shed or a few hundred board feet of gaps, and a $400 kit plus $115 of safety gear beats it by about $330. The DIY guide is written for that job.
How pros price it
Per board foot, by foam type, with a minimum. The quote should name the board feet, the foam (open-cell or closed-cell), the depth and resulting R-value, and what’s included in prep. The hire-a-pro page has the full list. The lines that move the price most:
- Thickness — price is per inch, so the code R-value for your climate zone sets the depth. R-30 is about 8.5 inches of open-cell or 5 of closed-cell.
- Removal — old fiberglass or cellulose has to come off a roof deck first, $1–$2 per square foot.
- Coverings — an ignition barrier over foam in an attic or crawl space, drywall over foam in a garage or living space. Not optional, often not in the first quote.
- Access — a tight attic with trusses on 24-inch centers is slow; an open pole barn is fast.
Before anyone sprays
Two things. Everyone out — occupants and pets leave for the spray and the cure, typically 24 hours or more, because isocyanate vapor causes permanent respiratory sensitization. What changes — foaming a roof deck seals the attic, which means roof vents get closed, a furnace or water heater up there needs combustion air, and the HVAC may need to condition the space. If the crawl space is part of the plan, the crawl space insulation comparison covers where foam makes sense down there.
Run your own numbers. The spray foam insulation cost calculator prices it both ways: as DIY, with the tools you already own and a value on your time, or as a pro job at a low, typical or high quote with the add-ons that apply.
Frequently asked questions
How much does spray foam insulation cost per square foot?
It's priced per board foot — one square foot at one inch deep — so the per-square-foot price depends on thickness. Open-cell at $0.60–$1.20 a board foot is $4–$8 per square foot at a typical 7 inches (R-25); closed-cell at $1.30–$2.50 is $4.50–$9 per square foot at 3.5 inches (R-21 to R-25). For a quick estimate, most residential spray foam lands at $4–$9 per square foot of surface, plus removal of old insulation and code-required coverings.
How much does it cost to spray foam an attic?
$5,000 to $11,000, typically about $7,500, for a 1,500 sq ft home — that's roughly 1,800 sq ft of roof deck once you account for pitch, at 7 inches of open-cell or 3.5 inches of closed-cell. Removing old blown-in or batt insulation first adds $600–$2,500, an ignition-barrier coating over the foam $750–$2,000, and a sealed attic may need a combustion-safety check and a supply register for $300–$1,500. Attic floors are rarely spray-foamed; foam goes on the roof deck to bring the attic inside the envelope.
Is closed-cell or open-cell spray foam cheaper?
Open-cell is cheaper per board foot ($0.60–$1.20 vs $1.30–$2.50) but has half the R-value per inch (3.5 vs 6–7), so you need twice the depth. On a finished job the gap narrows: R-21 in a wall is about 6 inches of open-cell at $3.60–$7.20 per sq ft or 3.5 inches of closed-cell at $4.50–$8.75. Closed-cell also adds a vapor retarder, water resistance and racking strength, which is why it's specified for rim joists, crawl spaces, garages and pole barns. Open-cell is the usual choice for attic roof decks and interior walls where it can flex and dry.
Is DIY spray foam insulation worth it?
Only for small jobs. A two-part kit costs $1.30–$2.00 per board foot depending on size and delivers 70–85% of the rated yield, so your real cost is about what a contractor charges installed. On rim joists, a shed or a few hundred board feet of gaps, the pro's $600–$1,500 minimum charge makes the kit the better deal: about $570 all-in against $900. On a garage you save about $500 for a day in a respirator; on an attic or a barn you spend as much or more than a quote and do the work yourself.
How much does a DIY spray foam kit cost?
About $400 for a 200 board-foot closed-cell kit ($2.00 per board foot) and $700–$1,000 for a 600 board-foot kit ($1.30–$1.60). The kit includes the two tanks, hose, gun and tips. Add $60 for a full-face respirator with organic-vapor cartridges, $30 for coveralls, gloves and goggles, and $25 for masking and cleanup. Real-world yield is 70–85% of the box rating, so budget one extra kit on anything bigger than rim joists.
How much does it cost to spray foam a garage?
$2,600 to $5,000, typically $3,500, for a two-car garage's walls and ceiling at 2 inches of closed-cell (about 2,000 board feet). Doing it from kits is $2,915–$3,085. Either way, code requires a thermal barrier — normally 1/2-inch drywall — over foam in a garage, which adds $1,500–$5,000 if the garage isn't already finished. Many contractors quote 2 inches in a garage because it's an unconditioned space; a heated workshop should go to 3 inches or more.
How much does it cost to spray foam a pole barn?
$7,000 to $13,000, typically about $9,500, for a 30×40 building's walls and roof at 2 inches of closed-cell (about 6,000 board feet), or $1.00–$1.80 per board foot — lower than residential rates because the surfaces are big, open and fast. Larger buildings scale close to linearly: a 40×60 is about $14,000–$22,000. From kits the same barn is $9,115–$9,415, a saving of about $235 for 20–35 hours of work, before the ignition-barrier coating a shop needs.
How much does spray foam cost for rim joists?
$600 to $1,500 from a contractor, typically about $900, for the rim joist of a 1,500 sq ft basement at 2 inches of closed-cell — roughly 200 board feet. Almost all of that is the minimum charge. It's the one spray foam job where a DIY kit clearly wins: a 200 board-foot kit and safety gear come to $515–$625 for 3–5 hours of work. If a contractor is already spraying something else in the house, adding the rim joist is $300–$1,200 instead.
How much does spray foam insulation cost for a 2,000 sq ft house?
$12,000 to $30,000 for new construction — walls and roof deck — depending on climate zone and foam type, with most in the $15,000–$22,000 range. That's roughly 2–3 times the cost of fiberglass batts for the same house. For an existing house, spray foam is used where cavities are open: the attic roof deck ($6,000–$13,000 for 2,000 sq ft), rim joists, crawl space walls and any wall that's been gutted. Finished walls get blown-in cellulose or injection foam instead.
Sources
- Insulation Workers, Floor, Ceiling, and Wall (SOC 47-2131), Occupational Employment and Wage Statistics , U.S. Bureau of Labor Statistics, 2026-04
- How Much Does Spray Foam Insulation Cost? , HomeGuide, 2026-09
- How Much Does a DIY Spray Foam Insulation Kit Cost? , HomeGuide, 2026-09
- How Much Does Spray Foam Insulation Cost? , Angi, 2026-09
- Types of Insulation , U.S. Department of Energy, 2026-09
- Quick Safety Tips for Spray Polyurethane Foam Users , U.S. Environmental Protection Agency, 2026-09
- International Residential Code, Section R316: Foam Plastic , International Code Council, 2026-09
Figures last reviewed . See how we estimate.