Underfloor insulation in Beaconsfield & Cardinia Shire.

• R2.5 polyester batts (Knauf Earthwool Polyester or Autex GreenStuf) — non-itch, non-absorbent, ideal for sub-floor moisture conditions. Our default. ~$32–$50/m².
• R2.5 glasswool batts (Earthwool, Bradford) — cheaper, suitable where sub-floor ventilation is well-drained and dry. ~$30–$45/m².
• Stainless-steel wire mesh support — mandatory to hold batts permanently against the underside of joists. Galvanised wire fails in sub-floor moisture within 5–8 years; stainless lasts the life of the house.
• Sub-floor vent rebalancing — counter-intuitive: insulation works better when sub-floor ventilation is balanced not blocked. We check existing vent area against AS 1684 requirements.

Why suspended-floor homes lose so much heat.

A pre-1990 Beaconsfield or Pakenham weatherboard home with a suspended timber floor over an open sub-floor loses heat two ways: conduction through 90mm of floor joist plus floorboards (effective R-value about R0.5), and convection drafts coming up through gaps between aged floorboards. Combined, your feet are cold and the gas heater runs constantly to replace the heat going down. Insulating the underside fixes both.

Restricted-access sub-floors — the Beaconsfield gotcha.

Many older Beaconsfield homes have sub-floor crawl spaces under 600mm at the lowest point. We work in those (it's our specialty) but it adds 15–25% to the install cost because progress is slower and we need extra crew. If your home has a sub-floor entirely under 400mm we may recommend lifting selected floorboards from above to install batts — quoted separately depending on floor type.

Sub-floor moisture — the honest pre-check.

About 10% of Beaconsfield / Pakenham heritage homes we quote have underlying sub-floor moisture problems — rising damp, poor drainage, blocked or insufficient ventilation. We won't install batts in a damp sub-floor — the insulation performs poorly and may trap moisture against the joists, causing rot. We assess at the free site visit and tell you honestly: fix damp first, then insulate. Sometimes the damp fix costs more than the insulation; that's still better than wasting both jobs.

Pricing.

• R2.5 polyester batts with stainless wire mesh: $30–$50/m²
• Restricted-access sub-floor (under 600mm): +15–25%
• Sub-floor vent rebalancing: included in standard install
• Typical 120m² Beaconsfield weatherboard: $3,600–$6,000
• Damp/drainage remediation (if needed): quoted separately