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Underfloor & Crawl Spaces

Spray Foam Underfloor Insulation

Stop cold floors and drafts from below. We spray timber floors and crawl spaces from underneath, so your floors stay in place.

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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 & Crawl Spaces

Warmer floors, sealed from underneath

Floors lose comfort through gaps, drafts and uninsulated subfloors. Spray foam adheres directly to the underside of the floor, sealing gaps between boards and joists as it insulates.

Because the foam is applied from below, underfloor insulation can suit existing homes as well as new builds, provided there's enough access to the subfloor. We check the crawl space and recommend the right system and R-value.

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.

Underfloor Insulation near you

Expert Answers

Underfloor Insulation FAQs

What people ask about underfloor insulation, 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

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

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1300 614 134

Email us

info@sprayfoamaustralia.com.au
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