If you are selling your home, organising paperwork or checking an older window or door installation, you may be asked for a FENSA certificate. It can feel worrying if you cannot find one, but a missing certificate does not always mean something is wrong. The best next step depends on whether the installation was registered, who completed the work and whether there is another form of building regulations evidence available. Here is a clear guide for homeowners.
A FENSA certificate is used as evidence that replacement windows or doors comply with relevant Building Regulations and that the installation has been registered with the local council. It is commonly requested during the sale of a property because buyers and solicitors want to see proof that the work was carried out and recorded correctly.
If you do not have the certificate, try not to panic. It may simply have been misplaced, or the work may have been certified through a different competent person scheme or local authority building control. The right approach is to gather as much information as possible before assuming you need replacement work.
The simplest step is to check whether the installation was registered with FENSA. You can search by address or certificate details through the official FENSA certificate service. If a matching record is found, you can order a replacement certificate.
This is usually the quickest route if the original paperwork has simply been lost. It is worth checking spellings, postcodes and any old address details carefully, particularly if the property has changed name, been renumbered or had work completed by a previous owner.
Not every compliant installation will necessarily have a FENSA certificate. The work may have been completed through another approved scheme, such as another competent person scheme, or it may have been approved directly by local authority building control.
Look through any documents left by previous owners, guarantees, invoices, installer details, completion certificates or conveyancing paperwork from when you bought the property. If you know the installer, contact them and ask what scheme they used and whether they can help trace the record.
Missing certification often becomes urgent during a house sale, so it is best to raise the issue with your solicitor or conveyancer as soon as possible. They can advise what evidence the buyer is likely to accept and whether any extra steps are needed.
Avoid contacting the local authority before taking legal advice during a sale, as this can affect the options available to you. In some cases, your conveyancer may suggest further searches, additional paperwork or another practical route depending on the age of the installation and the buyer's requirements.
If there is no FENSA record and no other evidence of building regulations approval, your local authority building control team may be able to advise on a regularisation application for unauthorised building work. This is a retrospective route used where work was carried out without the correct building regulations process.
The council may need information about the installation and may ask for parts of the work to be inspected or opened up. If the work does not meet the relevant requirements, remedial work may be needed before a certificate can be issued.
If you are replacing windows or doors now, ask the installer at quotation stage how the work will be certified and what paperwork you will receive. A FENSA Approved Installer can register qualifying replacement window and door work and provide the relevant certificate after completion.
Keeping the certificate, guarantee and invoice together will make future sales, remortgages or property checks much easier. It also gives you confidence that the installation has been handled through the right route from the start.
If the windows or doors were installed many years ago, the paperwork expectations may be different. Older installations may pre-date the current certification process, or the property file may simply be incomplete. Your solicitor, local authority or installer can help you understand what applies to your specific situation.
A missing FENSA certificate on its own does not prove poor workmanship, but it does mean you should check the available evidence carefully. Signs such as draughts, failed sealed units, condensation between panes, damaged frames or difficult operation may point to a practical replacement need as well as a paperwork issue.
If you are unsure whether your current windows or doors should be replaced, Harveys Windows can help you assess the condition, performance and appearance of your existing installation. Our team can also advise on replacement windows and doors where the correct paperwork and certification route can be discussed from the start.
Contact Harveys Windows to talk through your project, request a quote or get friendly guidance before replacing windows or doors in your home.
Click here to check out all our FENSA compliant window range.
Source / claim check: FENSA states that a FENSA certificate proves replacement window and door installations comply with Building Regulations, use energy efficient products and are registered with the local council. GOV.UK explains that competent person schemes allow registered installers to self-certify certain building work. The Building Regulations 2010, Regulation 18, covers regularisation applications for unauthorised building work. Date checked: 27 May 2026.
Publishing note: This article is general homeowner guidance, not legal advice. Check current FENSA, GOV.UK and local authority guidance before publishing, and signpost homeowners to their solicitor or local building control team where appropriate.