Attic Insulation · St. Louis, MO

Attic Insulation in St. Louis, MO: 2026 Costs & Local FAQs

Updated 2026-10-18 · Reviewed by the HomeServiceBud Editorial Team

Quick answer

Attic insulation in St. Louis typically costs about $1,700–$2,500 nationally, or roughly $1–$3 per square foot of attic floor. Adjusted for Missouri prices, plan on roughly $1,600–$2,400. In St. Louis, the biggest local factors are high humidity.

Key takeaways

  • Typical cost in St. Louis: $1,600–$2,400 (per attic); national range $1,700–$2,500.
  • Biggest local factors: high humidity.
  • How long it takes: Blowing in insulation for a 1,000 sq ft attic can take a few hours; larger jobs take up to two days.
  • Permits: Insulation rarely needs a permit, but local codes set minimum R-values.
  • Best timing: Spring and fall are the most comfortable times to work in the attic.
  • Before you hire: get at least three written, itemized quotes from licensed, insured Missouri contractors.

What St. Louis homeowners should know

St. Louis has hot, humid summers, cold winters and frequent severe thunderstorms, hail and tornadoes. Its historic brick homes, many over a century old, have full basements and original masonry that needs tuckpointing over time.

The region sits near the New Madrid seismic zone, one of the most significant earthquake risks in the central U.S., and clay soils can contribute to settling in older neighborhoods.

How much does attic insulation cost in St. Louis, MO?

Attic insulation typically costs $1,700–$2,500, with an average around $2,100. Insulation type, attic size and removal of old material drive the price. Missouri prices run 3% below the U.S. average, so a typical St. Louis job lands around $1,600–$2,400. Local labor rates, permit fees and your home's specifics move the final number.

Type / itemTypical cost (per sq ft installed)Notes
Blown-in (fiberglass or cellulose)$1–$4Fills gaps well
Batts or rolls$2–$4DIY-friendly
Loose-fill$2–$5
Spray foam$2–$5Also air-seals
Radiant barrier$0.50–$2Best in hot climates
Structural insulated panels$4–$7
Old insulation removal$1–$1.50If wet, moldy or pest-damaged

As a large city, St. Louis has plenty of contractors competing for work, which helps on price, but busy seasons can mean longer waits. Book early after major storms.

How we calculate costs

National ranges come from published cost surveys (cited below). Local estimates apply an approximate state cost index. Read our methodology.

Attic Insulation cost questions for St. Louis, MO

  • What is the cost of blown-in (fiberglass or cellulose) in St. Louis, MO? The typical cost of blown-in (fiberglass or cellulose) in St. Louis, MO is $0–$0 (typical cost per sq ft installed), adjusted for Missouri prices (national $1–$4). Fills gaps well.
  • What is the cost of batts or rolls in St. Louis, MO? The typical cost of batts or rolls in St. Louis, MO is $0–$0 (typical cost per sq ft installed), adjusted for Missouri prices (national $2–$4). DIY-friendly.
  • What is the cost of loose-fill in St. Louis, MO? The typical cost of loose-fill in St. Louis, MO is $0–$0 (typical cost per sq ft installed), adjusted for Missouri prices (national $2–$5).
  • What is the cost of spray foam in St. Louis, MO? The typical cost of spray foam in St. Louis, MO is $0–$0 (typical cost per sq ft installed), adjusted for Missouri prices (national $2–$5). Also air-seals.
  • What is the cost of radiant barrier in St. Louis, MO? The typical cost of radiant barrier in St. Louis, MO is $0.48–$0 (typical cost per sq ft installed), adjusted for Missouri prices (national $0.50–$2). Best in hot climates.
  • What is the cost of structural insulated panels in St. Louis, MO? The typical cost of structural insulated panels in St. Louis, MO is $0–$10 (typical cost per sq ft installed), adjusted for Missouri prices (national $4–$7).
  • What is the cost of old insulation removal in St. Louis, MO? The typical cost of old insulation removal in St. Louis, MO is $0–$1.46 (typical cost per sq ft installed), adjusted for Missouri prices (national $1–$1.50). If wet, moldy or pest-damaged.
  • What is the cost of air sealing in St. Louis, MO? The typical cost of air sealing in St. Louis, MO is $240–$730 per project (typical cost per sq ft installed), adjusted for Missouri prices (national $250–$750 per project). Often done first.
  • What is the cost of 1,000 sq ft attic in St. Louis, MO? The typical cost of 1,000 sq ft attic in St. Louis, MO is $970–$2,900 total (typical cost per sq ft installed), adjusted for Missouri prices (national $1,000–$3,000 total).

What affects attic insulation in St. Louis

High humidityHumidity around St. Louis can dampen insulation; wet fiberglass or cellulose can grow mold, so fix leaks and ventilate.

St. Louis has humid summers and cool-to-cold winters. Spring and fall are the most comfortable times to work in the attic.

Signs you need more attic insulation

  • Insulation sits below the top of the floor joists
  • High heating or cooling bills
  • Ice dams or large icicles in winter
  • Uneven room temperatures or drafts
  • Compacted, wet or animal-damaged insulation

Common questions about attic insulation in St. Louis

How much does attic insulation cost in St. Louis, MO?

Most attic insulation projects cost about $1,600–$2,400 in St. Louis, MO, or roughly $1–$3 per square foot of attic floor nationally.

How much attic insulation do I need?

ENERGY STAR recommends about R30 in the hottest climate zone, R49 in zones 2–3 and R60 in zones 4–8 for an uninsulated attic.

How much does it cost to remove old attic insulation?

Removal typically costs $1–$1.50 per square foot and is only needed if insulation is wet, moldy or pest-damaged.

Is spray foam attic insulation worth it?

Spray foam ($2–$5/sq ft) also air-seals, which can help efficiency, but blown-in or batts cost less for a simple top-up.

Timeline, permits and DIY in St. Louis

How long it takes

Blowing in insulation for a 1,000 sq ft attic can take a few hours; larger jobs take up to two days.

Permits

Insulation rarely needs a permit, but local codes set minimum R-values. Check with the St. Louis building department for local rules.

DIY or hire a pro?

Batts are DIY-friendly; blown-in and spray foam are best left to pros, and test old loose-fill for asbestos.

Questions to ask St. Louis contractors

Ask every bidder the same questions so you can compare quotes apples to apples.

  • What R-value will I have when you're done?
  • Is air sealing included?
  • How will you keep vents and soffits clear?
  • Will you remove damaged insulation first?

Maintenance that prevents costly repairs

  • Check insulation depth every few years
  • Keep soffit vents clear
  • Fix roof leaks fast to keep insulation dry

How to hire for attic insulation in St. Louis

  1. Ask what R-value the quote will achieve.
  2. Confirm air sealing is included or quoted separately.
  3. Ask how they'll handle old, damaged insulation.
  4. Check for utility or state rebates before you sign.

Attic Insulation in St. Louis: FAQs

How much does attic insulation cost in St. Louis, MO?

Nationally, most attic insulation projects cost $1,700–$2,500, about $1–$3 per square foot.

What R-value do I need in St. Louis?

ENERGY STAR recommends R30 to R60 depending on climate zone; check the St. Louis building code for local minimums.

How much does attic insulation cost in St. Louis compared to the national average?

With Missouri's regional cost index of 0.97, expect roughly $1,600–$2,400 in St. Louis, versus $1,700–$2,500 nationally.

How long does attic insulation take in St. Louis?

Blowing in insulation for a 1,000 sq ft attic can take a few hours; larger jobs take up to two days. Permit and inspection scheduling in St. Louis can add a few days.

Do I need a permit for attic insulation in St. Louis?

Insulation rarely needs a permit, but local codes set minimum R-values. Confirm with the St. Louis or county building department.

Which St. Louis ZIP codes does this guide cover?

This guide applies to St. Louis ZIP codes 63101, 63102, 63103, 63104, 63106, 63107, 63110, 63118, 63150, 63155, 63169, 63180, 63182, 63188, 63190, 63196, 63197, plus the surrounding area.

Attic Insulation near St. Louis

East Saint Louis, IL
3 mi away · pop. 27,006Venice, IL
3 mi away · pop. 1,915Cahokia, IL
4 mi away · pop. 14,402Madison, IL
4 mi away · pop. 3,868Alorton, IL
5 mi away · pop. 1,933Centreville, IL
5 mi away · pop. 5,027Washington Park, IL
6 mi away · pop. 3,990Granite City, IL
6 mi away · pop. 29,054Fairmont City, IL
6 mi away · pop. 2,502

Other home services in St. Louis

HVACAC, furnace and heat pump repair, replacement and costs$6,800–$11,600RoofingRoof replacement, leak repair, hail damage and insurance$6,500–$24,300Kitchen RemodelingKitchen remodel costs, timelines, permits and ROI$9,700–$67,900Bathroom RemodelingBathroom remodel costs, timelines, showers and ROI$6,400–$17,500Water Damage RestorationLeaks, floods, burst pipes, drying and insurance$1,200–$5,200Fire Damage RestorationFire, smoke and soot cleanup, odor removal and insurance$2,800–$37,200Mold RemediationMold removal, testing, costs and insurance$1,500–$4,900Garage Door RepairSprings, cables, openers, off-track doors and costs$80–$650Foundation RepairCracks, settling, piers, slab repair and costs$2,100–$7,600Water Heater ReplacementTank, tankless and heat pump water heater costs, permits and haul-away$860–$1,800Sewer Line Repair & ReplacementSewer line repair, dig replacement and trenchless pipe bursting or lining costs$1,300–$5,200Slab Leak RepairFinding and fixing leaks under a concrete slab: detection, reroute and lining$610–$4,300Electrical Panel Upgrade100 to 200 amp upgrades, panel replacement, meter and subpanel costs$1,300–$2,900Window ReplacementNew window costs by type, frame material and installation method$290–$2,000Siding ReplacementSiding costs per square foot by material, plus removal, labor and permits$8,200–$19,400Gutter InstallationGutter costs per linear foot by material, plus downspouts, guards and removal$600–$1,600

Sources: HomeAdvisor — Attic insulation cost · Bob Vila — Attic insulation cost · ENERGY STAR — Recommended home insulation R-values. Ranges are rounded estimates; see our editorial policy.

Local risk factors reflect general Missouri climate patterns; check FEMA's National Risk Index for county-level ratings. Local estimates apply an approximate regional cost index to national ranges.