Do Replacement Windows and Doors Need Building Regulations Approval? A Guide for Lancashire Homeowners

If you're replacing windows or doors anywhere in England, from a terrace in Bacup to a detached home in the Ribble Valley, the work is covered by the Building Regulations. That surprises many homeowners, and it's one of the most common questions we're asked during surveys. The good news is that, with the right installer, you shouldn't need to deal with Building Control at all. Here's how it works, what the rules require and what paperwork you should get at the end.

Are replacement windows and doors covered by Building Regulations?

Yes. In England, replacement windows, external doors, roof windows and rooflights are classed as "controlled fittings". That means the new units must meet minimum standards, mainly for energy efficiency, but also for safety glazing, means of escape, ventilation and, in some cases, security.

Building Regulations approval is needed whether you're changing one window or the whole house. It applies to aluminium, uPVC and timber alike, and it applies to doors that are more than 50% glazed as well as to composite front doors.

Repairs are different. Replacing a broken pane of glass, a handle or a hinge, or re-hanging an existing door, isn't normally notifiable. Replacing the whole frame is.

What is a Competent Person Scheme?

There are two ways to show the work complies:

1. 1.Apply to your local authority's Building Control (for us that's usually Rossendale, Burnley, Rochdale or Bury council, or another authority), pay a fee, and have the work inspected.
2. 2.Use an installer registered with a government-authorised Competent Person Scheme, who can self-certify that the installation meets the regulations.

GOV.UK lists the authorised schemes for replacement windows and doors in existing homes. They include ASSURE, FENSA, CERTASS, Certsure, NAPIT and Blue Flame Certification. A registered installer notifies the local authority for you. You should then receive a compliance certificate within eight weeks of completion.

Behind The Glass is an Assure Certified Installer. When we replace windows or doors, the job is registered through the scheme, so you don't need to make a separate Building Control application. You can check any installer's registration on the Competent Persons Register before you sign anything.

What standards do new windows and doors have to meet?

The main requirement for replacements in an existing home is thermal performance, set out in Approved Document L. For a replacement window or door, the whole unit (frame and glass together, not just the glass) should achieve a U-value of no worse than 1.4 W/m²K. There's an alternative route using Window Energy Ratings: Band B for windows, Band C for doors that are more than 60% glazed, and Band B for other doors.

Other rules can apply depending on where the window or door goes:

• ▸Safety glazing in "critical locations", such as glazed doors, side panels and low-level glass near floors, so toughened or laminated glass where required.
• ▸Means of escape: replacement windows serving upstairs habitable rooms that were escape windows should keep an escape opening at least as good as before.
• ▸Ventilation: if you remove trickle vents, the replacement shouldn't make ventilation worse, so we'll advise whether vents are needed.
• ▸Thresholds and access: a new door shouldn't make access worse than the old one.

A good installer will check all of this at survey stage, not on fitting day.

Do I need planning permission as well?

Building Regulations and planning permission are separate. Replacing windows and doors like-for-like is usually "permitted development" for a house, so planning permission isn't normally needed. The exceptions matter in our area, though:

• ▸Listed buildings need listed building consent for almost any change to windows or doors.
• ▸Conservation areas (there are several in Rossendale, Burnley and the Ribble Valley villages) may have an Article 4 Direction that removes permitted development rights for front elevations.
• ▸Flats and maisonettes don't have the same permitted development rights.
• ▸New openings, enlarged openings or new bi-fold openings in an extension may need planning permission alongside the extension.

If you're unsure, check with your local planning authority before ordering. That's especially worth doing for heritage-style doors and slim aluminium windows on older stone properties, where the look is part of what's being judged.

What paperwork should I get at the end?

After a replacement window or door installation by a scheme member, you should have:

• ▸a compliance certificate from the Competent Person Scheme (it usually arrives by post or email within eight weeks)
• ▸product details, including the U-value or energy rating of what was fitted.

Keep these with your house deeds. When you sell, your buyer's solicitor will ask for the certificate. Without it, you may need retrospective approval or an indemnity policy, which can delay a sale.

What happens if windows were fitted without approval?

If a previous owner or installer didn't register the work, the local authority can technically require it to be put right, and it can come up during conveyancing. Options usually include applying for a regularisation certificate from Building Control, or the buyer accepting an indemnity policy. It's far easier to make sure the installer is registered before work starts.

How we handle it at Behind The Glass

Every survey we carry out covers the technical side as well as the look. That includes checking the U-values of the systems we're proposing, flagging any safety glazing or escape requirements, and pointing out where planning or conservation rules may apply. We fit aluminium and uPVC windows, composite doors, bi-folding doors and rooflights across Rossendale, Burnley, Rochdale, Bury and the wider North West, and we register qualifying installations through Assure.

If you'd like a straight answer for your own property, book a free, no-obligation survey.

Frequently asked questions

Do I need building regulations approval to replace my windows?

Yes. Replacement windows in England must comply with the Building Regulations. If your installer is registered with a Competent Person Scheme such as Assure or FENSA, they can self-certify the work, and you won't need to apply to Building Control yourself.

Is Assure the same as FENSA?

Both are government-authorised Competent Person Schemes for replacement windows and doors. Either lets a registered installer self-certify that the work complies and issue a compliance certificate. Neither is "better" for the homeowner; what matters is that your installer is registered with one of them.

What U-value do replacement windows need?

For replacement windows and doors in an existing home in England, the whole unit should achieve a U-value of 1.4 W/m²K or better, or meet the equivalent Window Energy Rating (Band B for windows).

How long does it take to get my certificate?

Under the GOV.UK guidance, you should receive your compliance certificate within eight weeks of the work being completed.

Do I need planning permission to replace windows in a conservation area?

Possibly. Like-for-like replacements are usually permitted development, but some conservation areas have Article 4 Directions that remove that right, and listed buildings always need consent. Check with your local planning authority before ordering.

Does replacing a front door need building regulations?

Yes. Replacing a complete external door, including a composite front door, is notifiable. A Competent Person Scheme installer can certify it for you.