Planning & Regulations · 3 min read
Do I Need Planning Permission for New Windows or Doors?
Most window and door replacements do not need planning permission, but several common situations change that answer.
Can I Enlarge a Window Opening Without Planning Permission?
Sometimes, but never assume it. Enlarging an opening can fall within permitted development on an unconstrained house, and almost never does on a listed building or a principal elevation in a conservation area.
3 min read
Written by Windows in the Lakes · A trading name of Home Glazing Ltd · Last reviewed 21 September 2026
Short answer
In short: this is one of the few glazing questions where a generic answer is genuinely unsafe. Whether planning permission is required depends on your property's designation, its planning history, which elevation is affected and exactly what you are proposing. What is always true is that enlarging an opening is structural work subject to Building Regulations.
This guide explains the questions to ask and who to ask them of, rather than pretending to give you an answer for a house we have not seen.
Two separate approvals, often confused
| Planning permission | Building Regulations | |
|---|---|---|
| Concerned with | Appearance, amenity, designation and impact | Structure, safety, thermal performance and escape |
| Applies to enlargement? | Depends on designation and elevation | Yes — structural alteration always engages it |
| Decided by | Local planning authority | Building control body |
| Can be avoided by a small change? | Sometimes | No |
It is entirely possible to need Building Regulations approval but not planning permission. It is not possible to need planning permission and safely skip Building Regulations.
What affects the planning answer
- Whether the building is listed — in which case listed building consent is very likely to be required.
- Whether the property is in a conservation area, a National Park or subject to an Article 4 direction.
- Which elevation is affected; principal elevations facing a highway are treated more restrictively.
- Whether permitted development rights have been removed, which is common on newer estates and converted buildings.
- Whether the property is a flat or maisonette, where permitted development rights differ substantially.
- The scale of the change and whether it introduces overlooking of a neighbour.
The structural side
Widening an opening means a new lintel or beam, appropriate bearings, and temporary support while the work is carried out. On a stone building it can also mean careful dismantling and rebuilding of the reveal. This is work for a builder with a structural design from an engineer, not something a glazing installation resolves.
- 01Establish the planning positionBefore any design work or expenditure.
- 02Get a structural designAn engineer specifies the support over the new opening.
- 03Notify building controlThrough your builder's route or a full application.
- 04Form the openingBuilder's work, with the opening sized to suit the intended glazing.
- 05Survey and manufactureAfter order, we survey the formed opening and confirm manufacturing dimensions.
Terms used in this guide
- Permitted development
- Work that may be carried out without a planning application because national rules already allow it, subject to conditions and limits. It does not remove the need for building regulations compliance.
- Article 4 Direction
- A direction made by a local planning authority that withdraws specific permitted development rights in a defined area, so work that would normally be allowed requires a planning application.
Sources and further reading
Regulatory and technical points in this guide should be checked against the current published guidance below, and against the specific circumstances of your property.
- Planning Portal — Doors and windows
- GOV.UK — Approved Document A, structure
- GOV.UK — Building regulations approval
Guidance last reviewed 21 September 2026 by Windows in the Lakes
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