UK foil & multifoil insulation specialists

Foil insulation. Surveyed properly. Installed properly.

Looking at foil or multifoil insulation for your loft or roof? InsulationMatch helps UK homeowners understand whether reflective insulation suits their property, compare the available options and arrange professional installation where appropriate.

Check my home Explore foil insulation

Property-first recommendations
Nationwide service coverage
Foil & multifoil specialists
Independent insulation guidance
Professional installation options

Find out whether foil, multifoil, PIR or wool is right for your roof.

The Check My Home diagnostic asks about the roof, the loft, existing insulation and moisture, then shows a likely route and an indicative cost. No contact details until you have seen the answer.

Free. About two minutes. Value first, details second.

Loft room is freezing No headroom for thick boards There is spray foam in the roof Condensation on the rafters Planning a loft conversion

Where is your home losing heat?

Select the roof, loft, walls or floor to see what usually goes wrong there and which insulation routes apply.

Why foil is different.

Heat leaves a roof three ways. Wool and board slow conduction with thickness. Foil attacks radiation — but only across an air space, and only when the moisture side of the build-up is designed too.

RadiationA low-emissivity surface facing an air space emits and absorbs a fraction of the infrared plaster or timber would.
ConductionHeat through solid material. Foil pressed flat does almost nothing about it; the quilt's wadding core and any PIR do.
ConvectionHeat carried by moving air. Sealed still spaces help; ventilated voids do a different job — removing moisture.
Air spacesPart of the certified system, commonly ≈20–25mm per face. Air gap guide
VapourMost internal foils are vapour-resistant: right on the warm side, wrong on the cold side. Vapour control
VentilationThe cold side must breathe or moisture has nowhere to go. Condensation

Foil solutions, by where it goes.

Seven guides, one for each way foil is actually used in a UK home.

Foil insulationThe complete homeowner guide Foil wrapWhich of five products the term means MultifoilThe certified quilt for roofs and loft rooms Foil loft insulationRafters yes, floor rarely Foil roof insulationThe pitched-roof build-up Foil between raftersThe headroom-first detail Foil under raftersThe standard detail

Our position

We don't believe every home needs foil insulation.

That may sound unusual from a website aiming to become one of the UK's strongest foil-insulation resources. But it matters.

Foil and multifoil can be extremely useful in the right construction. In another property, mineral wool, PIR or a different insulation approach may be more appropriate. InsulationMatch exists to help identify the right route for the property — not simply the product somebody searched for.

Find my insulation match

How installation works.

Survey, assess, recommend, quote, install. The product is chosen at step four, not step one.

01Check the property
Postcode, construction, roof type, intended use.
02Inspect the roof and loft
Covering, timbers, existing insulation, access, services.
03Review ventilation and moisture
Eaves, ridge, membrane, staining, condensation history.
04Determine the insulation route
Multifoil, PIR, wool or a combination — chosen for this roof.
05Specification and quotation
Written build-up, certificate, target U-value, fixed price.
06Installation
Air gaps formed, joints taped, ventilation protected, photographed.
07Quality control and handover
Checked against the specification; documents and photographs handed over.

Arrange my home assessment Our installation standard

Technical authority, written to be checked.

Every claim on these pages points at a certificate, an Approved Document or a British Standard. A multifoil roof is a system; take away any one part and the certificate no longer applies.

Air gapsAir spaces and core resistance, separately CondensationPosition and ventilation rules U-valuesU, R, lambda and the whole element Vapour controlThree layers, three jobs Building RegulationsWhen approval applies ThicknessThin is not equivalent Fire performanceClass is not construction How it is installedPrinciples over staples

The roof build-up, layer by layer

Projects, explained properly.

Six typical project scenarios show how each situation is assessed and which routes come out of it. Completed InsulationMatch projects join the library as they are documented.

Cold loft, limited rafter depthWhen thin insulation earns its place Spray foam removed — what next?Timbers, membrane, ventilation, then replace When foil is not the answerRight property, right build-up, right insulation

Open the project library

Foil and multifoil against the alternatives.

There is no universal winner. Pick what matters and we will highlight the options usually considered for it.

Material	Typical use	Thickness	Installation	Moisture	Cost band	Trade-off
Mineral wool	Loft floor to 270mm; between joists and studs	270mm loft; 100–150mm walls/rafters	Simple; DIY-friendly	Breathable; needs a ventilated loft	Lowest cost per m²	Bulky; crushes if boarded over
PIR board	Rafters, warm roofs, floors, solid walls	50–150mm	Cut and fit; needs sealing at joints	Vapour-tight face; detailing matters	Mid to high	Rigid; awkward around services
Multifoil	Rafters, loft rooms, floors where depth is tight	30–45mm plus air gaps	Fast; staple and tape; needs air gaps both sides	Vapour control built in; air gaps must be kept	Mid; higher per m² than wool	Performance depends on installed air gaps
Blown cavity fill	Cavity walls built after 1930s	50–100mm cavity	Specialist injection; half a day	Needs a dry, suitable cavity	Low per m²	Not for narrow, damp or exposed cavities
EWI / IWI systems	Solid-walled homes; whole-house retrofit	60–120mm	Specialist; disruptive	Must be designed for moisture	Highest	Cost and planning considerations

Mineral wool

Use: Loft floor to 270mm; between joists and studs
Thickness: 270mm loft; 100–150mm walls/rafters
Install: Simple; DIY-friendly
Moisture: Breathable; needs a ventilated loft
Cost: Lowest cost per m²
Trade-off: Bulky; crushes if boarded over

PIR board

Use: Rafters, warm roofs, floors, solid walls
Thickness: 50–150mm
Install: Cut and fit; needs sealing at joints
Moisture: Vapour-tight face; detailing matters
Cost: Mid to high
Trade-off: Rigid; awkward around services

Multifoil

Use: Rafters, loft rooms, floors where depth is tight
Thickness: 30–45mm plus air gaps
Install: Fast; staple and tape; needs air gaps both sides
Moisture: Vapour control built in; air gaps must be kept
Cost: Mid; higher per m² than wool
Trade-off: Performance depends on installed air gaps

Blown cavity fill

Use: Cavity walls built after 1930s
Thickness: 50–100mm cavity
Install: Specialist injection; half a day
Moisture: Needs a dry, suitable cavity
Cost: Low per m²
Trade-off: Not for narrow, damp or exposed cavities

EWI / IWI systems

Use: Solid-walled homes; whole-house retrofit
Thickness: 60–120mm
Install: Specialist; disruptive
Moisture: Must be designed for moisture
Cost: Highest
Trade-off: Cost and planning considerations

Multifoil vs PIR · Multifoil vs mineral wool · Foil vs spray foam · Full comparison

What it is likely to cost.

A sourced indicative range, not a quote. Area, access, what is there now, whether PIR is combined and the finish move the price; fixed prices follow the survey.

Property type

Insulation routeTypical floor areas are assumed for each property type. Your quote will use measured areas.

Indicative installed cost

£0 – £0

Bands are compiled from published UK cost guides and installer input, compiled and reviewed 3 September 2026. They are wide on purpose. Methodology.

Get local quotes

Get my property estimate All insulation costs

Current funding routes.

Dated, and reviewed at least monthly. Eligibility criteria always apply.

Open

Warm Homes: Local Grant

England. Delivered through local councils for eligible lower-income households in less efficient homes. Insulation is a core measure. Eligibility criteria apply.

Who may qualify

Ends 31 Dec 2026

ECO4

Great Britain. Energy supplier obligation covering loft, cavity and other measures for eligible households, typically on certain benefits or via council referral. Closing to new work at the end of 2026.

ECO4 explained

Closed 31 Mar 2026

Great British Insulation Scheme

The GBIS eligibility service has closed and the scheme ended. Anything still advertising GBIS applications is out of date.

Current routes

InsulationMatch is not a government service and is not affiliated with GOV.UK or Ofgem.

Questions homeowners actually ask.

Does foil insulation actually work?

Yes, in the right build-up. A certified multifoil with 20–25mm air gaps on both faces is a mainstream roof insulation. Thin bubble foil pressed flat under rafters is not. The evidence.

Will you tell me if foil is the wrong choice?

Yes, and we quote the alternative. Open loft floors almost always get a mineral wool recommendation.

How much does multifoil to the rafters cost?

Roughly £45–£80 per m² installed, or £2,000–£6,500 for a typical semi-detached roof. Fixed after survey. Cost guide.

Does it need building control?

A roof slope, yes. The specification states the target U-value and who signs it off. Regulations.

Can foil cause condensation?

On the cold side or in an unventilated roof, yes. On the warm side with a ventilated void, it reduces it. Detail.

What if there is spray foam in the roof?

It is assessed separately first. Nothing is fitted over or against it until the foam and the timbers have been inspected. Spray foam.

Not sure whether foil insulation is right for your property?

Two minutes. See the likely route before anyone visits.

Check my home Arrange a home assessment

Free, no obligation. If foil isn't the right solution, we'll tell you.