FENSA-Compliant Window Installation
AMB Joinery is registered with FENSA — the Fenestration Self-Assessment Scheme — and every replacement window and external door we install in England and Wales is certified under the scheme. You will receive your FENSA certificate within 30 days of completion, giving you the documentation you need for building regulations compliance and for any future property sale.
This page explains what FENSA certification means in the context of our work and why it matters for London homeowners.
What FENSA Registration Means in Practice
FENSA is a government-approved competent person scheme that allows registered installers to self-certify that replacement window and door work meets building regulations — specifically Part L (thermal performance) and related structural and safety requirements.
When you use an AMB Joinery installer for replacement windows or doors, the process works like this:
- We carry out the survey, design, manufacture and installation
- On completion, we register the installation with FENSA
- FENSA issues a certificate recording the address, installer, date and certificate number
- You receive the certificate within 30 days
The certificate is held on the FENSA register and can also be downloaded at any time from fensa.org.uk using your postcode. It remains on record indefinitely.
Why the Certificate Matters
Building regulations compliance. Replacement windows in England and Wales must comply with building regulations. The FENSA certificate is the primary evidence that this requirement has been met. Without it, you are potentially in breach of regulations.
Property sale. When you sell your home, your solicitor will ask for evidence of building regulations compliance for any replacement windows installed since 2002. A FENSA certificate satisfies this requirement immediately. Without one, you face delays: either applying for a retrospective local authority regularisation certificate (which involves an inspection, a fee and time) or taking out indemnity insurance (which covers liability but does not fix the underlying compliance gap).
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This situation is very common with properties where windows were replaced informally in the 1990s and 2000s — often by unregistered traders who issued no paperwork. If you are buying a property and the windows were replaced without documentation, our FENSA register guide explains your options in detail.
What FENSA Covers
FENSA certification applies to replacement windows and external doors in existing dwellings. It covers:
- Standard replacement windows (including roof windows and skylights)
- Replacement external doors
- Compliance with Part L energy efficiency requirements (minimum U-value standards)
- Relevant safety and ventilation requirements
FENSA does not apply to:
- New build properties (covered by building control separately)
- Windows in listed buildings (which require Listed Building Consent regardless)
- Structural changes to window openings (enlarging or moving an opening requires separate building control)
For work in conservation areas or listed buildings, we advise on the correct consent route as part of the survey. See our sash window replacement service for how we approach planning and conservation requirements.
FENSA Certification and Double Glazing Upgrades
Where we replace sash panels within an existing box frame — for example, as part of a double glazing upgrade — the work may also qualify for FENSA certification, depending on the scope. We confirm the certification route at the quote stage so there are no surprises at handover.
Where work does not fall within FENSA's scope (for instance, draught-proofing or repair-only works), we advise on what documentation, if any, is required.
Our FENSA Registration Number
Our FENSA registration number is displayed on our website, our quotes and our invoices. You can verify our registration status at any time via the 'Find an Installer' tool at fensa.org.uk. Any window or door installer who cannot produce a registration number should be treated with caution.
Frequently Asked Questions
Do all AMB Joinery window installations come with a FENSA certificate?
Yes — all replacement window and door work we carry out in England and Wales that falls within FENSA's scope is registered. You receive your certificate within 30 days of completion.
I've lost my FENSA certificate from a previous installation. Can I get another?
Yes — visit fensa.org.uk, click 'Check a Certificate' and enter your postcode. If the installation was registered, you can download a replacement copy. If nothing comes up, the work may not have been registered, in which case our FENSA register guide explains the next steps.
Does FENSA cover listed buildings?
No. Listed buildings require Listed Building Consent from the local planning authority for any window alteration. FENSA is not a relevant mechanism for listed buildings.
What happens if windows were previously installed without FENSA certification?
You have three options: apply for a retrospective regularisation certificate from your local building control department; take out indemnity insurance at point of sale; or replace the non-certified windows with new, certified units. We can advise on which route makes most sense for your situation.
Get a Free Survey
If you are planning window or door replacement and want the peace of mind that comes with FENSA certification, contact us to arrange a free site survey. We will confirm the compliance route, agree the specification and make sure the documentation is in order before work begins.
