If you've been quoted for multifoil and the R-value on the data sheet looks impressive, there's a short paragraph you should read first — and it's the BBA certificate, not the marketing brochure. Multifoil performance is almost entirely dependent on the install detail: air gaps, overlaps, tape quality, and the direction of the reflective face. Install the same product 10mm outside its stated air-gap spec and the declared R-value collapses by 30%.
The BBA certificate is the document that separates the real number from the brochure number. Here's how to read one, what each of the main multifoil products actually guarantees in 2026, and the installation caveats that make or break the warranty.
The BBA (British Board of Agrément) certificate is the binding document — not the brochure. Learn to read it and you can specify multifoil properly. Ignore it and you end up with a product fitted outside its certification, a useless guarantee, and a building control officer who queries the SAP calculation.
What a BBA certificate actually covers
A BBA certificate is a product-specific assessment issued by the British Board of Agrément, an independent testing body. For a multifoil, the certificate typically runs to 15-25 pages and covers: product description, thermal performance (R-value and U-value for each application), fire classification, vapour control, durability, installation procedure (with required air gaps, fixings, and membranes), and building regs compliance routes.
Building control officers and SAP assessors are required to accept BBA-certified performance figures. That is why the BBA certificate — not the product brochure — is what gets submitted with a planning or building regs application. Any claim made in the brochure that is not in the BBA certificate is marketing, not guarantee.
The three brands we specify — side by side
Actis, SuperFOIL and TLX dominate the UK BBA-certified multifoil market. Each has a different strength and a different certification envelope. Here are the headline numbers as stated on their current BBA certificates — not the marketing material.
Why R-values differ between brands
Three factors drive the spread. First, layer count — Actis Hybris uses 19 reflective layers in a quilted structure, SuperFOIL SF60 uses 19 non-woven bonded layers, TLX Silver uses a thinner membrane reliant on large air gaps. Second, core material — some use recycled wadding, some use closed-cell foam cores, some are pure foil stacks. Third, the air gap built into the certification — TLX Silver's 1.70 R-value assumes a 50mm air gap on both sides, totalling 100mm of installed thickness; the product itself is only 10mm.
That third factor is what catches installers and homeowners out. A brochure that says "R-value 1.70" without the installed-thickness context is selling you a 10mm product that needs 100mm of air gaps to deliver the claimed figure. Install it in a 50mm cavity with no airgap and you get R-value around 0.60. Your building control officer will reject the SAP calculation.
How to read a BBA certificate properly
Section 1 — Product identification
Verify the certificate number matches the product you are buying. Manufacturers occasionally relaunch products under new names; the old BBA may not cover them. Cross-check on the BBA website (live database, searchable).
Section 2 — Declared performance
The R-values are stated here, with the specific application and build-up they relate to. Look for the build-up diagram and copy it exactly on your install. If your installer is quoting an R-value that does not appear in the certificate, walk away.
Section 3 — Installation procedure
The binding installation instructions. Fixings, air gaps, overlap widths, taping requirements, vapour control layer continuity — all listed. An OMEGA install is photographed and logged against this section. The photo pack goes to the homeowner as part of the sign-off.
Section 4 — Durability and warranty
Typical statement is 25-year durability when fitted per the certificate and protected from UV and mechanical damage. This is the warranty period that backs your guarantee. If the installer goes out of business, the BBA certificate stays live and the manufacturer honours the product warranty via it.
Common installation mistakes that void the BBA
- Air gap reduced — rafter depth forcing the insulation tight against the sarking felt. Adds moisture risk and kills the declared R-value.
- Taped seams skipped — vapour ingress at every joint. The multifoil's vapour control is joint-continuous by design.
- Wrong fixing centres — BBA cert specifies centres (typically 250-300mm for rafters). Wider centres cause sag and gap at the edges.
- Product compressed — multifoils rely on thickness retention. Compressing to fit a narrow stud voids performance.
- UV exposure — multifoil left exposed to sunlight during a long install window degrades the reflective coating. Cover within 30 days.
What OMEGA does differently
Every OMEGA multifoil install is specified against the live BBA certificate at survey stage, photographed during install to the same certificate's figures, and signed off with a certificate of as-built compliance. The homeowner receives a PDF pack with: product BBA number, install photos, U-value calculation, and 25-year transferable guarantee. It is the paperwork that holds up to building control, a future house sale survey, or a warranty claim.
BBA certificate FAQs
- Can I use a non-BBA multifoil?
- Technically yes, but you lose the ability to claim a declared R-value in SAP calculations and building regs. Building control officers routinely reject uncertified multifoil. You also lose the industry warranty backing. Avoid.
- How do I find a current BBA certificate?
- Go to bba.star.co.uk, search by product name or number. Every current certificate is there free to download. Certificates expire typically every 5 years — check the valid-to date before specifying.
- Are all Actis products BBA certified?
- No — Actis has a range of products, but only certain ones (Hybris, Triso-Super) carry the current BBA certification for loft, rafter or wall retrofit. Always check the specific product not the brand.
- Does BBA certification transfer to a new owner?
- Yes. The product certification is independent of the original purchaser. Our installation guarantee is also transferable — the 25-year warranty passes to the next owner at no cost when the house sells.
- What if the BBA cert changes after my install?
- Your install is assessed against the certificate live at the time of install. Later updates to the certificate do not retroactively invalidate your fitted product. BBA updates are rare and usually only tighten installation requirements.
- How does BBA compare to CE/UKCA marking?
- CE and UKCA marking confirm the product meets minimum EU or UK safety standards — a manufacturing compliance mark. BBA goes further: independent testing of the installed performance in a UK building context. For building regs and SAP calculations, BBA is the gold standard.
Book a proper multifoil specification
If your installer cannot tell you the BBA certificate number for the product they are quoting, the paperwork will not hold up. Book a free survey and we will specify a multifoil retrofit against its live BBA cert, in writing, with the as-built paperwork included. Ring freephone 0800 229 4094. No cost. No obligation. No pressure.
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