Planning permission for bifolding doors

Two separate things: planning permission vs Building Regulations

These get confused constantly. They are different processes.

Planning permission is about whether the change to your property is visually/structurally acceptable from a town planning perspective. Granted by your local planning authority.

Building Regulations approval is about whether the work meets construction safety, thermal performance and accessibility standards. Granted by building control (your council's building control department, or a private approved inspector).

For bifold installations: Building Regulations approval is always required. Planning permission is usually not required. Most installers (including us) handle Building Regulations via FENSA self-certification — you don't need to apply separately.

When you DON'T need planning permission

Under England's permitted development rules (Schedule 2 of the General Permitted Development Order 2015), you can install bifold doors without planning permission if:

• You're replacing existing doors or windows in the same opening
• You're installing new bifolds as part of a single-storey rear extension that complies with permitted development size limits
• The property is a normal house (not a flat, maisonette, or listed building)
• The property is not in a conservation area, AONB, National Park, or other designated land

Permitted development extension limits (the ones bifolds usually appear in):

• Single-storey rear extensions: up to 4m projection (detached houses) or 3m (semi-detached/terraced)
• Height: maximum 4m at the highest point
• Cannot exceed half the curtilage of the original house
• Cannot extend beyond the side wall by more than half the original house width

Larger extensions can still be permitted development under the prior approval process (up to 8m/6m) but require notifying the council, who then have 42 days to object.

When you DO need planning permission

• Listed buildings: any external alteration requires listed building consent, regardless of size. Most local authorities require timber bifolds in keeping with the period of the building.
• Conservation areas: rear elevation work is usually fine, but front and side elevation changes typically need planning permission. Check with your conservation officer before specifying.
• Flats and maisonettes: permitted development rights don't apply — planning permission is required for any external alteration.
• Article 4 directions: some areas have these in place, removing permitted development rights even for normal houses. Check with your local authority.
• New openings (knocking through a previously solid wall): often permitted development for rear elevations, but check — some councils interpret this differently.
• Extensions beyond permitted development limits: if your rear extension is over 4m (or 3m for terraced/semi), full planning permission is required for the extension, and the bifold gets included in that application.

Listed buildings — specific guidance

Grade I and Grade II* listed buildings: timber is almost always required. Modern aluminium is occasionally permitted on rear elevations of Grade II buildings, depending on the conservation officer and the visual context.

Even with timber, listed building consent requires specifying detailing that matches the period — putty-line glazing, traditional butt hinges, sash-style mouldings. We work with several conservation officers regularly and can help specify a system that meets approval.

Conservation areas

Conservation area status doesn't automatically prevent bifolds, but rear elevations are usually the only viable location. Front-elevation bifold installations in conservation areas typically need full planning permission and are usually refused if they're a significant visual change.

Some conservation areas also have Article 4 directions that remove permitted development rights entirely. Check your local authority website for "Article 4 direction map" or contact the planning department.

Building Regulations — what's covered

Bifold installations must meet:

• Part L (Conservation of fuel and power): U-value of 1.4 W/m²K or better for the whole door assembly
• Part Q (Security): applies to new dwellings only — PAS 24 certification required
• Part K (Protection from falling): safety glass below 800mm from floor level
• Part M (Access): if you're triggering access requirements, threshold height limits apply

FENSA self-certification covers Parts L and K automatically. Other parts may require building control involvement if your project goes beyond like-for-like replacement.

What to do if you're not sure

Contact your local planning authority and ask for a "Lawful Development Certificate". This is a formal confirmation that your proposed work is permitted development. Costs around £100 and takes 4–8 weeks. Worth doing for any borderline case — gives you legal certainty.

For listed buildings or conservation areas, contact the conservation officer at your local authority before specifying the bifold. They'll usually offer pre-application advice (free or low cost) on what's likely to be acceptable.

Scotland, Wales, Northern Ireland

The above applies to England. Scotland and Wales have similar but distinct permitted development regimes, with slightly different size limits. Northern Ireland has its own system. The principles are the same; the specific numbers vary. Always check with your local council.