FENSA Certificates Explained: What They Prove and Why They Matter

Straight answers first

Is a CERTASS certificate as valid as a FENSA certificate?

Yes, both are government-authorised competent person schemes and their certificates carry the same legal standing as evidence of building regulations compliance for window and door installations.

Do I need a FENSA certificate for every window I have replaced?

You need evidence of compliance for replacement windows and doors fitted since April 2002, which can come from FENSA, CERTASS or another relevant scheme, or from a local authority building control route.

What happens if I sell my house without a certificate?

The sale can usually still proceed, but the buyer's solicitor is likely to request either a replacement certificate, a building regulations indemnity insurance policy, or a retrospective regularisation certificate.

Can I get a duplicate certificate years after the work was done?

Often yes, both FENSA and CERTASS keep historic records and can usually issue a replacement or confirmation letter for a small fee if the original installer registered the job.

Is Wirral Windows FENSA registered?

No, we are CERTASS accredited, which is a separate but equivalent competent person scheme covering the same building regulations notification process.

Does a missing certificate mean the windows are unsafe?

Not necessarily. It means compliance cannot be immediately proven on paper, which is different from the work actually being defective, but it is still worth resolving before a sale.

What a FENSA certificate actually is

When you have replacement windows or doors fitted in England or Wales, the work has to comply with Part L of the building regulations, which covers thermal performance and safety glazing among other things. Rather than every household applying for a separate building control application, the government set up competent person schemes so that registered installers can self-certify their own work and notify local authority building control on the homeowner's behalf.

FENSA is one of those schemes, run for the glazing industry. When a FENSA-registered installer completes a job, they notify FENSA, and FENSA issues a certificate confirming the work has been registered and, subject to the standard checks, complies with the relevant building regulations at the time. That certificate is the paperwork you keep as proof the work went through the proper channel rather than being carried out with no oversight at all.

It is not the only competent person scheme

FENSA is well known because it has been around a long time and is heavily marketed, but it is not the only scheme covering window and door installation. CERTASS is another government-authorised competent person scheme doing exactly the same job, notifying building control and issuing a certificate of compliance when an installer completes a job under its rules.

We are CERTASS accredited rather than FENSA registered. A CERTASS certificate carries the same legal weight as a FENSA certificate for the purpose of proving building regulations compliance. Neither scheme is superior to the other in terms of what the paperwork proves, they are simply two separate competent person schemes covering the same trade, and it is worth being clear about which one your installer actually uses before work starts.

Why the certificate matters day to day

For most homeowners the certificate sits in a drawer and is never looked at again until something prompts a check, usually a house sale. But it does more than tick a bureaucratic box. It is the documented evidence that the installation was assessed against current safety glazing rules, thermal performance requirements, and ventilation standards at the time the work was done, rather than being fitted with no regard for any of that.

If a dispute ever arose about whether replacement windows met the regulations in force when they were installed, the certificate (whether FENSA or CERTASS) is the document that settles the question quickly, without needing to involve the local authority building control department directly.

Selling a house and conveyancing

This is where the certificate question comes up most often. When you sell a property, the buyer's solicitor will typically ask, via the standard TA6 property information form, for evidence that any replacement windows or doors fitted since April 2002 comply with building regulations. A FENSA or CERTASS certificate is the usual way to answer that question cleanly.

If you cannot find the certificate, it does not automatically mean the work was not compliant, but it does mean you cannot immediately prove it, which can slow down a sale or prompt the buyer's solicitor to ask further questions.

What to do if a certificate is lost or missing

The first step is straightforward: both FENSA and CERTASS keep records and can usually issue a replacement certificate or confirmation letter if you can tell them the address and roughly when the work was carried out. There is often a small administration fee for this, but it is generally the quickest fix if the installer used one of those two schemes.

If the installer was not registered with either scheme at all, or the company has since ceased trading and no record can be traced, a replacement certificate will not be available because none was ever issued or the record simply does not exist.

Indemnity insurance and building regulations completion certificates

Where no certificate can be traced, there are two common alternatives a solicitor may accept. The first is a building regulations indemnity insurance policy, a low-cost one-off policy that protects the buyer (and sometimes seller) against the cost of any enforcement action if the work later turns out not to comply. This does not prove compliance, it simply covers the financial risk of it not being provable.

The second alternative is applying retrospectively to the local authority building control department for a regularisation certificate, where an inspector assesses the existing installation against the standards in force when it was fitted. This route can involve inspection, possible remedial work, and a fee, and tends to be used less often than indemnity insurance because it is slower and less certain.

What to ask an installer before work starts

It is worth confirming a few things upfront rather than discovering them later. Ask which competent person scheme the installer is registered with, whether they will self-certify and notify on your behalf, and roughly how long after completion you should expect the certificate to arrive, since there is usually a short administrative lag between the job finishing and the certificate being issued.

• Which scheme are you registered with, FENSA or CERTASS or another
• Will the job be self-certified and notified to the scheme on completion
• How long after the work finishes should the certificate arrive
• What happens if the certificate does not arrive within that time
• Can duplicate certificates be requested in future if one is lost

Where we fit into this

We are CERTASS accredited and provide the relevant paperwork for work we carry out under that scheme, giving you the same building regulations assurance a FENSA certificate would provide, just through a different competent person scheme. If you are weighing up installers and this is part of your decision, it is a fair question to ask any company you are getting quotes from.