Underfloor Insulation Cost Australia — 2026 $/m² Guide
Expect $20–$45 per m² supplied and installed, or roughly $2,500–$5,500 for an average 120 m² suspended timber floor. Here's exactly what shifts your quote.
Cost by product (2026, installed)
| Product | R-value | $/m² installed | 120 m² home |
|---|---|---|---|
| Glasswool batts | R2.5 – R4.0 | $20 – $35 | $2,400 – $4,200 |
| Polyester batts | R2.5 – R4.0 | $25 – $40 | $3,000 – $4,800 |
| Rigid PIR / polystyrene | R2.0 – R3.0 | $35 – $55 | $4,200 – $6,600 |
| Spray polyurethane foam | R2.5 – R4.5 | $60 – $110 | $7,200 – $13,200 |
DIY material-only cost for polyester batts: $8–$15/m². Add sarking or vapour barrier: $4–$8/m².
Underfloor insulation cost estimator
Rough 2026 installed-price range for glasswool or polyester batts. Actual quotes vary by site access, product and location.
Auto-fills your state below
National average
Standard (500–700mm) — typical crawl space
Typical Australian home: 100–180 m²
Typical $/m² installed
$22 – $44
Total for 120 m²
$2,650 – $5,300
Estimate for R2.5–R4.0 batts, supplied and installed. Rigid boards or spray foam can be 1.5–3× higher. Add $4–$8/m² for sarking or vapour barrier.
Factors that increase your quote
- • Subfloor clearance under 500mm (+20–40%)
- • Higher R-value target (R3.5+ in VIC/TAS/ACT)
- • Damp, rot or termite remediation required
- • Restricted access (raised stumps, small hatches)
- • Sarking / vapour barrier add-on
- • Regional / remote install callout fees
Factors that reduce your quote
- • Open, walkable subfloor (>700mm clearance)
- • Bundling with ceiling or wall insulation
- • Choosing glasswool over polyester
- • Metro Melbourne / Hobart competitive market
- • Off-peak booking (autumn/spring)
- • State rebates via whole-home upgrade schemes
Get 3 underfloor insulation quotes
Compare installed prices from verified assessors and installers near you — no email, no signup, and we'll match your R-value target to NCC 2022 minimums.