Replacement windows and doors in Wales must meet building regulations, and a FENSA registered installer can certify the work for you without a building control visit. Daimant, the family-run installer based in Caerphilly, is FENSA registered and fits windows and doors across Cardiff and Caerphilly with the certificate included.
- FENSA registered
- 10-year insurance-backed guarantee
- Fixed written quote
- Our own Caerphilly fitting team
Fitted by our own Caerphilly team
Do replacement windows and doors need building regulations approval in Wales?
Replacement windows and glazed doors in Wales need to comply with building regulations, which the Welsh Government says have applied to all replacement glazing since 1 April 2002. You can meet that duty by using a registered installer, or by applying to a building control body yourself.
A registered installer handles the regulations for you, so the paperwork arrives without any effort on your part. The problems start when an installer is not registered, the paperwork is never issued, and the gap only shows up years later when you sell. Knowing the two routes before you sign saves that trouble.
| Registered installer (competent person scheme) | Unregistered installer or DIY | |
|---|---|---|
| Who checks the work | The installer self-certifies under the scheme | A building control body |
| Who tells the council | The installer or scheme operator | You, through your building control application |
| What you receive | A certificate showing a registered installer did the work | A certificate of compliance from building control |
| Your involvement | None beyond keeping the certificate | Application, fees and an inspection |
- All replacement glazing in Wales has had to meet building regulations since 1 April 2002.
- A registered installer under a competent person scheme, such as FENSA, certifies the work and notifies the council.
- You receive a certificate at the end, and you need it when you sell the house.
- The rules cover energy efficiency, safety glass, escape from upstairs rooms and ventilation.
- Planning permission is a separate question, mainly for conservation areas and listed buildings.
The registered route is the simpler of the two, so it helps to know what the scheme actually is.
What is a competent person scheme for windows and doors?
A competent person scheme is a government-authorised register of installers qualified to carry out specific work in line with building regulations without involving local authority building control. For windows and doors in existing homes in Wales, the authorised schemes include FENSA, CERTASS, Certsure, NAPIT, Blue Flame Certification, ASSURE and Stroma.
The Welsh Government’s guidance says a registered installer should notify the local authority of the work and issue you with a certificate of compliance, either directly or through the scheme operator. You do not apply for anything or pay building control fees. The installer carries that responsibility, and the scheme monitors them.
Which scheme is Daimant in?
Daimant is FENSA registered. Every window and door we fit is registered through FENSA, and the certificate comes as part of the job. Our about us page sets out how we work as a family firm with our own fitting team.
What does a FENSA certificate prove?
A FENSA certificate proves that your replacement windows or doors comply with building regulations, that the installation is energy efficient, that it is registered with the local council and that the installer’s guarantee is insured. FENSA describes itself as a government-authorised scheme monitoring building regulation compliance for replacement windows and doors.
Keep the certificate with the house deeds or the documents you keep for the property. FENSA advises homeowners to ask any installer whether they will receive a FENSA certificate when the job is done, and a registered installer should always say yes.
The guarantee on top of the certificate
The certificate is separate from the guarantee on the product and workmanship. Our windows and doors come with a 10-year guarantee, and it is insurance-backed, so it stands even if something happened to the business. Our guide to deposit protection, FENSA and guarantees explains how each layer protects your money.
Why do you need a FENSA certificate when you sell your house?
You need a FENSA certificate when you sell your house because it proves that any windows or doors replaced since April 2002 met building regulations. FENSA’s own guidance says the certificate is needed when selling a property, and it saves questions during the sale.
If you replaced windows years ago and cannot find the certificate, contact the installer or FENSA through its help centre. The work is recorded, so a copy can usually be traced. If the windows were fitted by an unregistered installer with no building control sign-off, you have a gap to resolve, and that is much harder to fix late in a sale than at the time of fitting.
Windows fitted before April 2002
Windows and doors fitted before 1 April 2002 were installed before the replacement glazing rules applied, so there is no certificate to find for them. If you are unsure when your windows went in, the date on a guarantee, an old invoice or the spacer bar inside the glass unit can help. Windows of that age are also likely to be showing their years, so they are worth checking against the signs you need new windows before you sell.
What happens if your installer is not registered?
An unregistered installer cannot self-certify the work, so you or the installer must apply to a building control body for approval, pay the fees and have the work inspected. The Welsh Government confirms that approval can be sought from the relevant building control body for unregistered or DIY work.
This route is legal and it works, but it moves the responsibility onto you. If no one applies, the windows have no certificate and the work may not meet the rules. Before you sign any contract, ask which scheme the installer belongs to and check their registration. The steps at the end of this guide show how.
What standards must new windows and doors meet in Wales?
New windows and doors in Wales must meet standards for energy efficiency, safety glazing, means of escape and ventilation, set out in the Welsh building regulations and approved documents. A registered installer specifies the window to meet them, and the certificate confirms it.
- Energy efficiency. Windows and doors must meet a limit on how much heat passes through them, measured as a U-value, set in the Welsh approved document for energy. The A-rated windows we fit sit around 1.2 W/m²K, and our composite and bifold doors around 1.4 W/m²K.
- Safety glazing. Glass in critical areas must be safety glass. That includes glazing within 800 millimetres of the floor, and glazing within 300 millimetres of a door up to 1,500 millimetres high.
- Means of escape. A replacement window must give at least the same potential for escape as the old one. Escape windows need a clear openable area of at least 0.33 square metres, and at least 450 millimetres high and wide.
- Ventilation. Rooms need suitable ventilation, with higher levels in rooms where steam is produced, such as kitchens and bathrooms.
Escape and safety glass matter most in bedrooms, on landings and in flats. Our guide on whether tilt and turn windows are safe for children explains how restrictors and escape work together upstairs.
Do you need planning permission as well as building regulations?
Most homes do not need planning permission to replace windows and doors with similar ones, but homes in a conservation area covered by an Article 4 Direction, and listed buildings, may need consent. Planning permission and building regulations are separate: one controls appearance, the other controls safety and performance.
Cardiff has 27 conservation areas, many with Article 4 Directions controlling minor changes such as windows, including Roath Park and Llandaff. Caerphilly County Borough Council also designates conservation areas and publishes a map. If your home might be affected, check with the council before ordering. Our guide to uPVC sash windows in a Cardiff conservation area covers Article 4 and listed homes in more detail.
Do bifold doors, new openings and conservatories follow the same rules?
Bifold and patio doors that replace existing glazed doors follow the same replacement glazing rules, while new or widened openings and some conservatory work bring in extra building control requirements. The difference is whether you are replacing glazing or changing the structure of the house.
New or widened openings
Cutting a wider opening for bifold doors, and fitting a new lintel, is structural work. Your surveyor tells you on the visit whether your job needs building control sign-off as well as the FENSA certificate. Our guide on what bifold doors cost in Cardiff covers the building work and its cost.
Conservatories
The Welsh Government’s guidance says a conservatory is usually exempt from building regulations if it is under 30 square metres of internal floor area, separated from the house by external quality walls, doors or windows, has no fixed heating or extended heating system, and has compliant glazing and electrics. Any new structural opening between the conservatory and the house needs approval. Replacing a translucent conservatory roof with a solid one is normally treated as needing building control involvement, and we tell you on the survey whether yours does.
How do you check an installer before you sign?
Check an installer before you sign by confirming which competent person scheme they belong to, checking their registration yourself and getting the certificate, guarantee and deposit protection promised in writing. It takes ten minutes and protects you for as long as you own the house.
Ask which scheme they are in
Ask the installer which competent person scheme they are registered with, such as FENSA or CERTASS.
Check the register yourself
Use the scheme’s own search, such as FENSA’s Find a FENSA Approved Installer tool, to confirm the company is listed.
Get the certificate in writing
Make sure the quote says you will receive a certificate when the work is complete.
Check the guarantee and deposit
Ask whether the guarantee is insurance-backed and how any deposit is protected.
Keep the certificate safe
When it arrives, file it with your house documents. You will need it when you sell.
We survey and fit across Cardiff and Caerphilly, and in Newport, Penarth, Barry, Bridgend, Pontypridd, Cwmbran, Pontypool and Blackwood, with the FENSA certificate included on every job.
Once the paperwork is clear, the next step is choosing the windows themselves. Our replacement windows in Caerphilly and Cardiff page compares every style we fit, all A-rated and built to PAS 24.
Frequently asked questions
Replacement external doors fall under the same Welsh guidance on doors and windows, and a FENSA registered installer certifies the doors they fit. Your installer confirms the paperwork for your door on the quote.
Contact FENSA through its help centre or ask the installer who fitted the windows. The installation is recorded, so a copy can usually be traced.
Both are competent person schemes authorised for windows and doors in existing homes in Wales. Either lets a registered installer self-certify the work.
Yes. The rules apply to all replacement glazing, including a single window. A registered installer certifies it in the same way as a whole house.
Yes. The survey is free, and the quote that follows is fixed, in writing and with no obligation to go ahead.
