Nobody thinks about window paperwork until the week a house sale wobbles. The buyer's solicitor sends over their enquiries, and there among the questions about boundaries and boilers sits a line asking for evidence that the replacement windows comply with building regulations. The seller stares at it. The windows went in eleven years ago. There is no paperwork. The firm that fitted them stopped answering the phone around 2019.
Why windows involve building regulations at all
Since 2002, replacing windows in England and Wales has counted as controlled building work, mainly because windows matter for heat loss, ventilation, fire escape and safety glazing. Compliance is shown one of two ways. Either the local authority inspects and signs the work off directly, or, far more commonly, the installer belongs to a competent person scheme such as FENSA or Certass and self-certifies, after which a certificate is issued for the property. That certificate is the document the solicitor wants. It says a registered installer confirmed the work met the regulations of the day.
What happens when it is missing
Here is the calming part: a missing certificate very rarely kills a sale. It slows one down and it hands the buyer a small stick in negotiations. Solicitors deal with it constantly and have routine fixes. The most common is an indemnity insurance policy, a one-off premium usually paid by the seller, which covers the buyer against the remote chance of the council taking enforcement action over the old work. It does not certify that the windows are any good; it just insures the risk away, and most buyers accept it.
The tidier fixes are worth trying first. FENSA and Certass both keep searchable records and can reissue lost certificates for a modest fee, so if you know roughly when the windows were fitted, start there before buying insurance against a document that may exist. Failing that, the local authority can inspect the windows now and issue a regularisation certificate, though this costs more, takes longer, and invites someone to look closely at old work.
If you are having windows fitted now
All of the above is avoidable at the point of purchase. Before signing with any installer, ask which scheme they are registered with and confirm the registration on the scheme's own website rather than taking a logo on a van as proof. After the job, the certificate typically arrives by post or email within a few weeks; chase it if it does not, while the firm still wants your goodwill. Then keep it with the guarantee documents in the same folder as your boiler paperwork, because the two get asked for at the same moment in every sale.
Choosing a firm that leaves you with clean paperwork
Certification is a decent first filter when comparing installers, because a firm that handles the paperwork properly tends to handle the fitting properly. When you are gathering names, look through double glazing companies covering your area and note who states their scheme registration plainly, or request quotes for your job and make the certificate question part of every conversation.
And if you are selling right now with no certificate in hand: ring FENSA and Certass today with your address and a rough installation year. A ten-minute search there has rescued more completion dates than any indemnity policy.
