Cost to Basement Insulation in Seattle, WA

$1,920–$8,320 in Seattle

28% above the national average · 1.28x cost multiplier

In Seattle, a basement insulation runs $1,920 to $8,320 on average — about 28% above what homeowners pay nationwide. The West Coast 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 Seattle

Line Item	Low	Mid	High
Cost per sq ft	$1	$3	$6
Materials	$768	$2,304	$4,480
Labor	$1,152	$1,920	$3,840
Permits	$0	$256	$384
Total	$1,920+28% vs. national avg	$4,480+28% vs. national avg	$8,704+28% vs. national avg

Budget

Fiberglass batt insulation in rim joists and walls of a small 600 sq ft unfinished basement - DIY-friendly approach

Mid-Range

Rigid foam board plus batt insulation for walls and rim joists in a 1,000 sq ft basement - solid thermal and moisture performance

Premium

Closed-cell spray foam on walls, rim joists, and ceiling of a 1,200 sq ft basement - maximum energy savings and moisture control

Material Options

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

Material	Cost/Unit	Pros	Cons	Best For
Fiberglass Batt Insulation	$0.50 - $1.50 per sq ft installed	Lowest cost, widely available, DIY-friendly, good R-value per dollar for rim joists	Absorbs moisture, can harbor mold if wet, not a vapor barrier, less effective on cold concrete walls	Rim joist insulation and interior stud wall cavities in dry basementsLowest cost, widely available, DIY-friendly, good R-value per dollar for rim joists
Rigid Foam Board (EPS or XPS)	$1.00 - $2.50 per sq ft installed	Moisture-resistant, adds R-value without moisture risk, can be cut to fit, some types act as vapor retarder	Requires fire protection (drywall) if left exposed, more labor to install neatly, seams need tape	Foundation wall insulation - best practice approach for most basementsMoisture-resistant, adds R-value without moisture risk, can be cut to fit, some types act as vapor retarder
Closed-Cell Spray Foam	$2.00 - $4.00 per sq ft installed	Highest R-value per inch (R-6 to R-7), complete air and vapor seal, fills gaps and irregular surfaces, longest-lasting option	Must be installed by licensed applicator, most expensive option, cannot be removed once cured, off-gassing during cure	Rim joists, irregular surfaces, and homeowners who want maximum energy performance and moisture controlHighest R-value per inch (R-6 to R-7), complete air and vapor seal, fills gaps and irregular surfaces, longest-lasting option
Open-Cell Spray Foam	$1.00 - $2.00 per sq ft installed	Good air sealing, softer and more flexible, lower cost than closed-cell, fills cavities completely	Lower R-value per inch (R-3.5 to R-4), absorbs moisture, needs vapor barrier in some climates	Interior applications where moisture is controlled and air sealing is the primary goalGood air sealing, softer and more flexible, lower cost than closed-cell, fills cavities completely
Mineral Wool (Rockwool) Batts	$1.00 - $2.00 per sq ft installed	Moisture-resistant, fire-resistant, excellent sound absorption, holds shape better than fiberglass	More expensive than fiberglass, heavier and slightly harder to cut, itchy to handle	Basements where fire resistance and sound dampening are priorities alongside thermal performanceMoisture-resistant, fire-resistant, excellent sound absorption, holds shape better than fiberglass

Other Projects in Seattle

Full Kitchen Remodel

Full Bathroom Remodel

Composite Deck Building

Back to national average for Basement Insulation

Seattle Estimate

Typical Range

$1,920–$8,320

vs. National Average

28% above national

Cost Multiplier

1.28x

Cost Per sq ft

$1–$6

Estimates apply Seattle's 1.28x regional cost multiplier to national averages. Actual bids vary by contractor, project scope, and timing.

See national average costs →