How do I check whether my windows have a FENSA certificate?

FENSA runs an address-based certificate search, and can issue a duplicate where one was originally lodged. If nothing comes back, ask your local authority building control too — work notified to the council produces a completion certificate rather than a FENSA one.

Can I sell my house without a FENSA certificate?

Sales do complete without one, but expect the enquiry and expect it to need answering. Your solicitor will advise on the options in your case, which commonly include evidence from the installer, a regularisation application to building control, or an indemnity policy — that last one satisfies a conveyance, not the Building Regulations.

Does a competent person scheme certificate replace building control?

For that work, in effect yes. Where the installer is registered with a designated competent person scheme, building control does not need to be notified, and the installer self-certifies that the work complies. That is the whole purpose of the scheme.

Is an insurance-backed guarantee the same as a certificate?

No. The certificate evidences compliance with the Building Regulations. An insurance-backed guarantee covers the installer's own workmanship promise if they cease trading. You can hold one without the other.

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Updated 30 August 2026

No FENSA Certificate For Your Windows

Your solicitor or buyer has asked for the paperwork proving your replacement windows were signed off, and you have not got it.

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Window and door fitting, illustrative image

What's happening?

Replacing a window in an existing home is building work. It has to comply with the Building Regulations, and compliance has to be evidenced. There are two routes. Either a building control body is notified and inspects, or the installer belongs to a competent person scheme and self-certifies the work — FENSA being the best-known scheme for windows and doors. Where a registered installer does the work, no notification to building control is needed, and the certificate they lodge is your evidence. If no certificate exists, it usually means one of three things: the windows predate the requirement, they were fitted by someone outside a scheme and never notified, or the paperwork was issued and has simply been lost. The three have very different remedies.

What usually causes it?

Windows installed before replacement windows became controlled work under the Building Regulations
Fitted by an installer who was not a member of any competent person scheme, and never notified to building control
Fitted by a registered installer who never lodged the certificate, or lodged it against the wrong address
Certificate issued years ago and lost during a move or a conveyance
The installer went out of business between doing the work and registering it
Work notified to the local authority instead, so the evidence is a building regulations completion certificate rather than a FENSA one
Only some of the windows were replaced at that time, so the certificate covers fewer openings than the buyer expects

Is it dangerous?

No. This is a paperwork and conveyancing matter, not a safety one. It bites at the point of sale: buyers' solicitors routinely raise it, and unevidenced building work is a standard enquiry. It can also matter for a guarantee claim, since scheme-backed insurance guarantees rest on the registration.

Can I fix it myself?

Start by checking whether a certificate exists — FENSA holds a search for exactly this, keyed to the address, and a duplicate can be requested where one was lodged. If nothing is registered, ask the installer directly, and check with your local authority building control in case the work was notified that route. What you cannot do is issue your own evidence, and it is worth knowing that an indemnity policy is not a way of complying with the Building Regulations, even where a solicitor is content to accept one to close a sale.

When should you call a window fitter?

Call a window fitter when the windows themselves may not meet the standard they were supposed to — a replacement with no trickle vents where the previous window had them, or thin single-glazed units in a recent installation. A registered installer can tell you what the existing installation is, and what bringing it up to standard involves. For the certificate itself, the scheme and your local authority are the route, not the fitter.

What will the window fitter actually do?

Survey the existing windows and record the glazing specification, ventilation provision and safety glass positions
Say plainly which openings would meet the current standard for a replacement and which would not
Quote remedial work — retrofitting background ventilators, replacing units that do not meet the limiting U-value
Carry out any replacement as a scheme-registered installer, so this installation is certificated
Lodge the certificate against the correct address and confirm it is registered

Frequently asked questions

We’re happy to answer all your questions.

Sources & References

No Trickle Vents After New WindowsCaution Gaps Around A New Window FrameCaution Rotten Wooden Window FrameCaution

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