Selling and buying a house without a FENSA certificate — understand the rules on replacement windows and doors
A home with double glazing that lacks FENSA – or equivalent – certification can cause delays or put a buyer off. This is what you need to know

Whether you’re selling or buying a house without a FENSA certificate, it’s vital to be aware that its absence can cause hold-ups in the conveyancing process. And it could even bring a halt to the sale.
During the process of buying a house, the purchaser’s legal enquiries can reveal that there isn’t certification from FENSA – or CERTASS or another government-approved scheme – that shows the installation of windows and/or doors complies with building regulations. Lack of this approval is the crux of the problem.
But what can you do as either a buyer or a seller if certification is missing? This is what you need to know.
What is a FENSA certificate?
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Since April 2002 in England and Wales replacement windows and doors must comply with building regulations. Typically, this is achieved by employing an installer who’s a member of a competent person scheme and can self-certify that their work complies with building regulations.
FENSA (the Fenestration Self-Assessment Scheme) was the first government-authorised scheme monitoring building regulations compliance for replacement windows and doors, and issues the FENSA certificate as proof that an installation is compliant. FENSA is not the only authorised scheme: CERTASS installers can also self-certify their work, as can those from the smaller Assure.
“It is not a FENSA or a CERTASS certificate that is required in and of itself, it is the evidence of compliance with building regulations that these certificates provide,” explains Natalie Beard, conveyancer at SAS Daniels. “A householder could alternatively apply for consent from the local authority although it would be a lengthier process,” she points out.
Be aware that not all works to windows and glazing require consent. “Windows or glazing installed before April 2002 will not necessitate consent,” says Natalie. “If it is merely a case of repairing broken glass, replacing fogged units or replacing parts of the window frame, building regulation consent is not required. Similarly, in the case of a door that contains glazing, if less than 50 per cent of the door and frame is glazed then consent is not required.”
Natalie Beard is a conveyancer in SAS Daniels’ residential property team. She has nine years’ experience working in conveyancing and is experienced at dealing with both existing homeowners and those embarking on the property ladder for the first time.
Selling without a FENSA certificate
If you don’t have evidence of building regulations compliance via a FENSA certificate, other government-approved scheme, or from the local authority when you’re selling a home, there are options open to you.
Lost certificate
If the only issue is that a FENSA certificate is lost, this is easy to solve. You can find and order a FENSA certificate. There is a fee of £25 for online orders and £30 if you pay by cheque.
Retrospective consent
As a seller, you could get in touch with the local authority.
“You can apply for retrospective consent from the local authority,” says Natalie Beard. “But you run the risk of them taking enforcement action against you for a breach of building regulations and you also may be required to carry out remedial works to make the works compliant before they will grant consent.”
Indemnity policy
“The easiest option would be to obtain an indemnity policy for breach of building regulations and this would financially protect you and your future buyer from enforcement action,” says Natalie Beard.
“These policies only seek to compensate the owner for any local authority enforcement action,” she says. “They do not stop the enforcement action and they also are of no assistance should the glazing work fail.”
Buying without a FENSA certificate
If you’ve put an offer in on a home that doesn’t have a FENSA certificate or other evidence of building regulations compliance, bear in mind that this can affect your mortgage application.
“Mortgage lenders require reassurance that any structural changes, including window and door replacements, comply with building regulations,” says Andrew Boast, founder of SAM Conveyancing.
“If a property does not have a FENSA certificate for its double glazing, lenders may view this as a potential risk, particularly if the work was carried out after 1 April 2002, when compliance became mandatory,” Andrew says. “The absence of a certificate raises concerns that the windows may not meet safety and thermal performance standards or that the installation was not done correctly. Some lenders may refuse to proceed with the mortgage until the issue is resolved, while others may require additional documentation or indemnity insurance to mitigate the risk.”
There’s a further complication. “Without a FENSA certificate, there is no automatic confirmation that the installation has been reported to the local authority,” says Andrew. “If the windows were installed without proper notification, the local authority has the legal right to demand retrospective approval or even require corrective work to be carried out. This could lead to unexpected costs and delays, which can impact the mortgage approval process.
“If a FENSA certificate is missing, steps can be taken to resolve the issue, but failing to address it could lead to delays or even the mortgage being declined,” he adds.
If this is the case, below are the options for a buyer.
Andrew Boast is the CEO, executive director and co-founder of SAM Conveyancing, and has over 23 years of experience in the home and conveyancing market. Andrew is an accomplished expert in his field, guiding thousands of clients through the complex process of buying a home both personally and through his teams of expert solicitors, surveyors and mortgage advisers.
Local authority records check
If it’s a case of a missing FENSA certificate, this can be replaced. See above for details.
But if the certificate can’t be found? “Another option is to check whether the local authority has a record of the installation in its building control records,” says Andrew Boast. “Some councils may have been notified even if the original certificate has been lost. Your solicitor can request this information as part of the conveyancing process.”
Retrospective consent
As we noted above, the seller can apply for a retrospective building regulation compliance certificate, often referred to as a letter of regularisation.
This can be time-consuming, Andrew Boast points out.
Indemnity insurance
Indemnity insurance is an option, as noted above. “The buyer can take out building regulations indemnity insurance,” says Andrew Boast.
But, as previously mentioned, there are limits to this cover. “Indemnity insurance does not cover physical defects in the windows or doors, nor does it apply if the local authority has already been informed of the issue,” Andrew says.
It would prove to be one of the additional costs of buying a house, and typically ranges from £180 to £500, Andrew says.
Questions about your glazing’s compliance with building regulations will be asked during conveyancing, and sellers should be aware that “a nervous buyer may be dissuaded by work carried out without the proper consents”, says Natalie Beard. And if you’re thinking of buying a home without FENSA certification, don’t forget that the same questions will be asked of you when you come to sell.
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Sarah is a freelance journalist and editor writing for websites, national newspapers, and magazines. She’s spent most of her journalistic career specialising in homes.
She loves testing the latest home appliances and products, and investigating the benefits, costs and practicalities of home improvement. She is an experienced renovator and is currently remodelling the ground floor of her new home.
She was Executive Editor of Ideal Home and has worked for Your Home and Homes & Ideas. Her work has published by numerous titles, including The Guardian, channel4.com, Houzz, Grand Designs, Homes & Gardens, House Beautiful, Homes & Antiques, Real Homes, The English Home, Period Living, Beautiful Kitchens, Good Homes and Country Homes & Interiors.