Spray Foam Australia
Get a Quote
Sydney depot, Prestons NSW 2170

Underfloor Insulation Sydney

Spray foam underfloor insulation for timber floors and crawl spaces across Greater Sydney, from our Prestons depot.

Get a Free Quote
Currently accepting bookings.
Call 1300 614 134
On-Site
Underfloor Insulation

Crawl Space Application

1. Sprayed from under the floor
2. Seals boards and joists
ISO 9001 • 45001 • 14001
EEC Accredited
Huntsman Approved
HIA Member
5.0 Google rating
2014
EstablishedNational Australian Operations
16k+
Homes InsulatedAcross WA, VIC, QLD & NSW
100+
Trained ProfessionalsAcross the Energy Efficiency Group
5.0
Google RatingVerified Customer Feedback
Underfloor Insulation in Sydney

Spray foam underfloor insulation for Sydney properties

Sydney's older homes and houses on sloping blocks often have timber floors above a ventilated subfloor. That can leave rooms cold underfoot in winter. Spray foam goes on from below, sealing gaps and adding insulation without lifting the floor.

Closed cell foam isn't water permeable, so it can suit Sydney's humid conditions once any existing subfloor moisture issue has been dealt with. Our Prestons crew works across Western and South West Sydney, the North Shore, Northern Beaches and the Hills District.

See the difference

Before and after

Underfloor Insulation, beforeBefore
Exposed floor framing with no insulation between the joists.
Underfloor Insulation, afterAfter
Closed cell foam applied across the underside of the floor.

Why insulate your floors with spray foam

  • Fewer drafts

    Foam expands as it's applied, sealing gaps between boards and around joists.

  • Moisture control

    Closed cell foam isn't water permeable, which suits spaces exposed to damp.

  • Works around services

    Sprayed in place, it reaches around pipes, wiring and irregular framing.

  • No floor removal

    Where there's access below, the foam goes on from underneath, so floors stay in place.

How it works

How we insulate an underfloor

  1. Exposed floor joists from belowStep 1

    Check the subfloor

    We inspect access, floor framing, services and any moisture concerns.

  2. Installers reviewing a project on siteStep 2

    Prepare the area

    The crew protects surrounding areas and readies the surfaces.

  3. Foam across the underside of a timber floorStep 3

    Spray from below

    Certified applicators spray the floor's underside, working around joists and pipes.

  4. Finished underfloor insulationStep 4

    Check and clean up

    We check the coverage, tidy the site and let you know when the area is ready.

Underfloor projects up close

Foam across timber floor joists
Foam applied between floor joists around plumbing
Spray foam across the ceiling of a lower-level laundry
Spray foam applied beneath a floor in a crawl space
Spray foam insulation under a raised floor

Underfloor Insulation R-values and thickness

Foam typeUsed inR-valueThicknessBest for
Closed cellUnderfloors, crawl spacesR1.024mmTight subfloors and moisture-prone areas
Closed cellUnderfloors, crawl spacesR2.048mmHigher thermal targets beneath timber floors

Indicative values only. These figures must be verified against the current manufacturer data sheets before they're used for design, specification or compliance. We confirm the final system, thickness and any required thermal barrier for each project.

NSW depot

Underfloor Insulation from our Sydney depot

Unit 4/1 Powdrill Rd, Prestons NSW 21701300 614 134

Dedicated local crew serving Sydney Metro & Regional NSW

Areas we cover
  • Greater Sydney & Western Sydney Hubs
  • South West Sydney, Liverpool & Campbelltown
  • North Shore, Northern Beaches & Hills District
  • Wollongong, Central Coast & Regional NSW
Book site visitEmail our team
Expert Answers

Underfloor Insulation Sydney FAQs

What people ask about underfloor insulation in Sydney, from access and R-values through to safety and cost.

Have a specific project question?

Our team can talk through your substrate, access, climate and the data sheets you need.

Ask Our Technical Team

Which Sydney areas do you service for underfloor insulation?

Our Prestons depot covers Greater and Western Sydney, Liverpool, Campbelltown, the North Shore, Northern Beaches and Hills District, along with Wollongong and the Central Coast.

Can you insulate under an existing timber floor?

Yes, if there's enough safe access beneath the floor. We spray from below, so the floorboards usually stay in place. We'll check your access and framing during the site assessment.

How much access do you need under the floor?

It depends on the layout and how far installers need to reach. Tell us what's under your home, or send photos, and we'll assess whether spray foam is practical.

Will underfloor spray foam help with drafts?

Foam expands as it's applied and seals gaps between floorboards and around joists, which helps reduce drafts coming up through the floor.

Does it stop moisture under the floor?

Closed cell foam isn't water permeable, and can help manage moisture at the floor. It doesn't fix an existing subfloor water problem, so any drainage or damp issue should be addressed first.

What R-value do I need for an underfloor?

That depends on your climate, the floor and your goals. As a guide, closed cell foam at about 48mm gives around R2.0. We confirm the system and thickness against current data sheets for your project.

Is spray foam safe to use in a subfloor?

Once cured, the foam is non-hazardous and free of formaldehyde and asbestos. It must be installed by licensed applicators wearing PPE while it's airborne, so people stay clear during application and return when the installer advises it's safe.

Is spray foam fire rated?

Spray foam is generally classified as a combustible material under the NCC, and fire performance is specific to the tested product and configuration. Ask us for the data sheet that applies to your project, and read our fire performance page for more detail.

How much does underfloor insulation cost?

It depends on the floor area, access and R-value. Contact us for a free, no-obligation quote.

More spray foam services in Sydney

Sydney spray foam consultations

Ready for a seamless experience?

Our spray foam consultants assess your property and recommend a practical, cost-effective solution for comfort and energy performance.

Call us

1300 614 134

Email us

info@sprayfoamaustralia.com.au
Prompt response during business hours No-obligation assessment

Get your free Sydney quote

This secure form sends your enquiry to our technical team, and we'll be in contact with you shortly.