Cost to Spray Foam Insulation in St. Louis, MO

$1,320–$5,720 in St. Louis

12% below the national average · 0.88x cost multiplier

In St. Louis, a spray foam insulation runs $1,320 to $5,720 on average — about 12% below what homeowners pay nationwide. The Midwest market's labor costs account for most of the gap, with material pricing and local permitting fees adding to the spread. Use the cost table below to compare budget, mid-range, and premium options side by side.

Cost Breakdown in St. Louis

Line Item	Low	Mid	High
Cost per sq ft	$1	$2	$5
Materials	$704	$1,496	$2,816
Labor	$528	$1,144	$1,760
Permits	$44	$88	$176
Design	$44	$352	$968
Total	$1,320-12% vs. national avg	$3,080-12% vs. national avg	$5,720-12% vs. national avg

Budget

Open-cell spray foam in an open attic floor or crawl space, 500-800 sq ft, 3-4 inches of coverage (R-13)

Mid-Range

Closed-cell spray foam on attic roof deck or basement walls, 800-1,200 sq ft, 2-3 inches of coverage (R-13 to R-19)

Premium

Full closed-cell spray foam application on roof deck and walls, 1,200-1,500 sq ft, 4+ inches (R-26+), with thermal imaging verification

Material Options

Material prices below are national averages; availability in St. Louis may shift costs slightly.

Material	Cost/Unit	Pros	Cons	Best For
Open-Cell Spray Foam (0.5 lb density)	$1.00 - $1.75 per sq ft per inch	Lower cost, excellent air sealing, good soundproofing, expands to fill irregular cavities	Lower R-value per inch, absorbs moisture (not for below-grade), requires vapor retarder in cold climates	Interior walls for soundproofing, attic roof deck in warm climates, above-grade applicationsLower cost, excellent air sealing, good soundproofing, expands to fill irregular cavities
Closed-Cell Spray Foam (2.0 lb density)	$1.75 - $3.50 per sq ft per inch	Highest R-value per inch, vapor barrier, adds structural rigidity, moisture resistant	Most expensive option, requires professional installation, off-gases during application	Basement walls, crawl spaces, attic roof deck in cold climates, thin wall cavities where space is limitedHighest R-value per inch, vapor barrier, adds structural rigidity, moisture resistant
DIY Spray Foam Kits	$1.50 - $2.50 per sq ft	No contractor needed, available at home improvement stores, good for small jobs	More expensive per sq ft for large areas, harder to apply evenly, limited coverage per kit	Rim joists, small gaps, band boards, supplemental insulation under 200 sq ftNo contractor needed, available at home improvement stores, good for small jobs
Hybrid System (Closed-Cell + Blown-In)	$1.50 - $2.50 per sq ft (blended rate)	2 inches of closed-cell for air/vapor barrier, then cheaper blown-in to reach target R-value	Two-step installation, requires coordination between trades	Attic roof decks and walls where you want closed-cell benefits at a lower total cost2 inches of closed-cell for air/vapor barrier, then cheaper blown-in to reach target R-value
Low-GWP Spray Foam (HFO-blown)	$2.00 - $4.00 per sq ft per inch	99% lower global warming potential than traditional HFC-blown foam, meets green building standards	10-15% more expensive, not available from all contractors	Green building projects, LEED certification, homeowners prioritizing environmental impact99% lower global warming potential than traditional HFC-blown foam, meets green building standards

Other Projects in St. Louis

Full Kitchen Remodel

Basement Finishing

Roof Replacement (Asphalt Shingles)

Back to national average for Spray Foam Insulation

St. Louis Estimate

Typical Range

$1,320–$5,720

vs. National Average

12% below national

Cost Multiplier

0.88x

Cost Per sq ft

$1–$5

Estimates apply St. Louis's 0.88x regional cost multiplier to national averages. Actual bids vary by contractor, project scope, and timing.

See national average costs →