Spray Foam Insulation Cost Long Island

2026 pricing guide · Updated October 2026 · 6 min read

Spray Foam Insulation Cost Long Island depends on foam type, thickness and access — but Nassau and Suffolk homeowners can plan with real 2026 numbers, not national averages. Long Island labor, disposal and travel push prices above the U.S. median, while larger suburban attics and basements give you better per-square-foot economics than a cramped city rowhouse. Here is how pricing actually works.

2026 Price Per Board Foot and Per Square Foot

Foam is sold by the board foot — one square foot, one inch thick. On Long Island in 2026, expect roughly $1.00 to $2.00 per board foot installed for open-cell and $1.80 to $3.20 per board foot for closed-cell, with small or difficult jobs at the top of the range. Converted to a finished surface, a 3-inch open-cell attic application often lands around $3.00 to $5.50 per square foot, while 2 inches of closed-cell in a basement is commonly $3.60 to $6.50 per square foot. See our open-cell vs. closed-cell comparison for R-value per inch.

What Changes the Quote in Nassau and Suffolk

Access matters most. A walk-up ranch attic in Levittown or Hicksville sprays fast. A Cape in Massapequa with low knee-wall voids, stored belongings and old fiberglass to remove takes longer. Finished basements, low ceilings and waterfront crawl spaces in places like Babylon, Long Beach and Bay Shore add masking and moisture prep. Thickness matters too: attics need more inches of open-cell to hit target R-value, while closed-cell reaches it thinner but costs more per inch.

Our attic insulation and basement insulation pages explain which foam fits each zone, and our Brooklyn cost guide shows the city comparison.

Rebates and Payback on Long Island

Check PSEG Long Island home performance and rebate programs and NYSERDA EmPower+ for income-eligible households before you sign — incentives change yearly and can offset a meaningful share on qualifying homes. Payback is usually driven by oil savings: a $5,000 attic and rim-joist job that cuts winter oil use by a quarter can save several hundred dollars a season, with added summer cooling savings on the South and North Shores. Most owners see payback in four to seven years, then save for decades.

Get every quote in writing with foam type, inches and square footage. If a price looks far below these ranges, ask what thickness is actually included.