Building regulations: replacing windows and doors
Replacing windows and doors is not just about aesthetics – it’s about safety, energy efficiency, and compliance with UK building regulations. Since June 2022 in England, all replacement glazing has been covered by revised building regulations to ensure properties meet thermal performance, ventilation requirements, fire safety, and accessibility standards.
Understanding these regulations is essential whether you’re replacing sash windows in a period home or upgrading doors in a modern property. This guide outlines everything you need to know to ensure your installation is fully compliant.
What do the UK building regulations for windows and doors include?
Building regulations exist to protect the health, safety, and energy efficiency of properties. They cover:
- Thermal performance (energy efficient windows compliance)
- Fire safety glazing requirements (escape routes and fire-resistant glazing)
- Ventilation and airflow
- Structural integrity and security
- Accessibility for people with disabilities.
If you install replacement windows or doors, you must ensure compliance. Simply replacing the glass is exempt, but changing the entire window or door is not.
When selling your property, buyers’ solicitors will request proof of compliance for any replacement glazing installed after June 2022. Without it, you may face delays or legal issues.
FENSA Certification: Hassle-free compliance
If you choose Sashed’s expert fitting service for replacement windows and or doors, your installation will be:
- Fully compliant with current UK building regulations
- Certified under FENSA (Fenestration Self-Assessment Scheme)
- Registered with your local authority.
Once installation is complete, FENSA will issue a Building Regulations Compliance Certificate, which will be posted directly to you. This proves compliance and is required if you sell your property.
Installing windows yourself? Here’s what you need to do
If you are installing our bespoke timber windows yourself or using an independent fitter, you must:
- Ensure compliance with England & Wales, Scotland, or Northern Ireland building regulations.
- Check if your installer is FENSA registered – if they are, they will handle compliance registration.
- If your installer is not FENSA registered, report the installation to your local authority building control (LABC) for inspection and certification. (Self-certified window installation)
For more details on FENSA, visit FENSA’s official website.
Building regulations for replacement windows
If you replace windows or doors and the existing units do not meet current building regulations, the new installation must not worsen the situation.
For example:
- You cannot remove fire escape windows and replace them with non-compliant alternatives.
- You cannot downgrade existing energy efficiency levels when upgrading windows.
For full compliance, where applicable your new windows should meet:
- Approved Document A – Structure
- Approved Document B – Fire safety and escape routes
- Approved Document C – Site preparation and resistance to contaminants and moisture
- Approved Document F – Ventilation
- Approved Document J – Combustion appliances and fuel storage systems
- Approved Document K – Protection from falling, collision and impact
- Approved Document L – Energy efficiency standards
- Approved Document M – Access to and use of buildings
Installing windows or doors into a new opening (extensions to existing properties)
For windows and doors installed into new openings (for example, as part of an extension or an addition to an existing property), you must engage your local Building Control department or an Approved Inspector to certify that the installations comply with current building regulations. Sashed will ensure, as part of our in‑depth survey process, that the windows meet the relevant building regulations.
Building regulations for new builds
For new-build properties, in addition to the above approved documents all windows and doors must comply fully with:
- Approved Document Q (security standards for new dwellings)
Find the complete regulations on the UK Government Planning Portal.
Installing conservation area or listed building windows?
In protected areas, conservation rules may override certain building regulations.
Do I need planning permission?
Building regulations and planning permission are separate requirements.
- If you replace like-for-like windows, you do not need planning permission (except in conservation areas).
- If you change window style, materials, or size, you may require permission.
- Listed buildings and Article 4 conservation areas have stricter requirements.
For full details, see our Planning Permission Guide.
Why choose Sashed for compliant window installations?
Expertise in conservation areas: We specialise in planning-compliant sash window replacements for heritage homes.
FENSA-approved installations: All projects meet UK building regulations.
Bespoke craftsmanship: Every timber sash window is tailored to your property.
Energy efficient and sustainable – We use the latest vacuum insulated glazing technology.
Planning and compliance support: We handle planning applications if needed.
Need advice on building regulations? Contact us today
For expert guidance on window and door compliance, get in touch with our specialists.
Call us: 020 3198 4472
Email us: [email protected]