Are bifold doors covered by FENSA?

FENSA is the route most homeowners use to certify replacement bifolds, but it only applies through registered installers. Here is what the scheme covers and what your options are.

What FENSA is and what it covers

FENSA (the Fenestration Self-Assessment Scheme) is a government-authorised competent person scheme for the replacement of windows and external doors in England and Wales. Its purpose is to provide a simple route for proving that replacement glazing complies with the Building Regulations without every job needing a separate building control application. Because bifold doors are external doors, replacing existing doors with bifolds falls squarely within what FENSA covers.

The mechanism is self-certification. A FENSA-registered installer is assessed as competent to ensure the work meets the Regulations — chiefly the thermal-efficiency requirement of Part L (the door's U-value) and the safe-glazing requirement of Part K (toughened or laminated glass). Having fitted the doors to standard, the installer notifies the local authority that compliant work has been done, and you receive a FENSA certificate. This certificate is the documentary proof that your replacement doors meet Building Regulations. It is worth understanding that FENSA itself does not inspect every installation; it registers and audits competent installers who take responsibility for compliance on each job. That is why using a genuinely registered, reputable installer matters.

FENSA, CERTASS and building control compared

There is more than one way to certify replacement bifolds, and it helps to know the alternatives:

• FENSA: the best-known competent person scheme for windows and doors. A FENSA installer self-certifies and you get a FENSA certificate.
• CERTASS: a directly comparable competent person scheme. A CERTASS-registered installer self-certifies in the same way and issues a CERTASS certificate. It does the same job as FENSA.
• Local authority building control: if your installer is in neither scheme — or you fit the doors yourself — you cannot self-certify. Instead you apply to building control before work starts, they inspect, and they issue a completion certificate.

All three result in valid, documented compliance. The difference is simply who certifies it: a registered installer (FENSA or CERTASS) bundling it into the job, or building control doing it through inspection. When choosing an installer, asking which scheme they belong to — and confirming their registration — is a sensible step.

Routes to certify replacement bifold doors. Sources: FENSA; Planning Portal.

Why the certificate matters and how to keep it

The FENSA (or CERTASS, or building control) certificate is not just bureaucracy — it is the document that proves your replacement doors are legally compliant, and it has real value when you come to sell. During conveyancing, a buyer's solicitor will ask for certificates for any windows and doors replaced since 2002, when self-certification began. If you cannot produce one, the sale can be delayed, and the buyer may insist on indemnity insurance or a retrospective building control application to be satisfied.

So the practical advice is simple. Use a registered installer, make sure the certificate is issued after the job (it is typically registered and sent to you, and you can usually retrieve a copy from FENSA later if mislaid), and store it with your house papers alongside warranties and other home documents. If your bifolds were fitted by a non-registered installer and no certificate exists, you cannot obtain a FENSA certificate retrospectively — but you can apply to building control for a regularisation certificate, which provides the same evidential reassurance. Keeping the paperwork in order from the outset is far easier than sorting it out under the pressure of a sale.

One further practical point: the certificate is registered against the property address, not your name, so it stays relevant to the home even after you move on. When you do sell, you simply hand it to the buyer as part of the bundle of property documents. If you have lost the original, FENSA holds a record and can usually reissue a copy for a small administrative fee, so a mislaid certificate is rarely a serious problem provided the work was genuinely registered at the time.

What FENSA does and does not cover

It is worth being clear about the boundaries of what a FENSA certificate represents, because it is sometimes misunderstood as a guarantee of quality or a workmanship warranty. In essence, the certificate confirms two things: that the replacement doors were registered as compliant with the relevant Building Regulations, and that the local authority was notified, satisfying the legal requirement for notifiable work. It is a compliance record, not a quality assurance for the doors themselves.

Several points follow from this. FENSA covers the replacement of windows and external doors in existing dwellings — which is exactly what fitting bifolds in place of old patio doors is. It does not cover structural work such as forming a new opening or installing a steel beam; that is separate building control territory and must be certified in its own right, even if the doors going into the new opening are FENSA-registered. FENSA also does not replace the manufacturer's product warranty or the installer's own workmanship guarantee, both of which are separate protections worth having alongside the compliance certificate. Some schemes offer an insurance-backed guarantee as an optional add-on, but that is distinct from the certificate's core purpose. Understanding this helps you assemble the full set of paperwork a bifold installation should leave you with: the compliance certificate, the product warranty, and the installer's guarantee — three different documents protecting three different things, and all worth keeping together.

To sum up, FENSA is the route most homeowners use to certify replacement bifolds, but it works only through a FENSA-registered installer; CERTASS provides an equivalent route, and building control covers everything else. Whichever applies to your job, the goal is the same: end up with a recognised certificate confirming the doors comply with the Building Regulations, and store it safely with your home documents so it is to hand when a buyer's solicitor asks for it.

Frequently asked questions

Sources & further reading

• FENSA — What is FENSA?
• GOV.UK — Competent person schemes
• Planning Portal — Building control applications

Figures on this page are typical UK ranges drawn from published sources and depend on your specific opening and material. They are guidance, not a quotation.