Do I Need Planning Permission for a Roof Light in 2026? (UK)

The short answer

If your roof light is flush-fit, on the rear or front roof slope of a house (not flat), projects no more than 150mm above the roof plane, sits 1.7m+ above floor level on side elevations, and your property is not listed, in a conservation area, AONB or under an Article 4 direction — you do not need planning permission. Building Regulations approval is a separate matter (almost always required for structural and thermal reasons).

The 5-step decision tree

Step 1: Is the property listed or in a designated area?

Listed buildings need Listed Building Consent for any roof light — there is no PD route. Conservation areas, AONBs, National Parks, World Heritage Sites and the Broads remove most PD rights for roof alterations on principal or side elevations visible from the highway. If yes to any of these, planning permission is required.

Step 2: Is there an Article 4 direction on the street?

Article 4 directions strip specific PD rights on specific streets — often roof alterations in residential conservation areas. Search your council's planning portal or order a Local Land Charges Search (£30–£80) to confirm.

Step 3: How far does the unit project above the roof plane?

Class C permits a projection up to 150mm above the original roof plane. Most flush-fit Velux GGL/GPL units sit well inside this; raised "sun tunnel" domes and roof lanterns frequently exceed it and need full planning.

Step 4: Is the unit on a side elevation, and how low does it sit?

On a side elevation, the bottom of the glazing must be 1.7m or more above the internal floor level to avoid overlooking concerns. Lower than that requires either obscure glazing fixed shut, or planning permission.

Step 5: Are you adding several units that exceed the roof slope?

While there is no statutory cap on the number of roof lights, a layout that visually constitutes a "new roof" rather than "openings in the existing roof" can lose PD on aesthetic grounds. Two or three units across a slope are universally accepted; ten in a row may not be.

Building Regulations — separate matter

Even if planning permission is not needed, Building Regulations approval almost always is. The contractor must notify Building Control of: structural changes to the roof joists, the thermal performance of the new unit (U-value ≤1.4 W/m²K), and fire-safety distance from neighbouring properties (1m minimum from a boundary). A FENSA- or CERTASS-registered installer can self-certify the thermal and fire elements; the structural element typically still needs a Building Notice.

Lawful Development Certificate — worth the £103?

Even when you are confident the work is PD, applying for a Lawful Development Certificate (LDC) at £103 gives you formal council confirmation. This protects you at resale — conveyancing solicitors increasingly require it. Turnaround is typically 8 weeks.

FAQs

Related guides

• Do I need planning permission for a loft conversion?
• Do I need planning permission for a roof extension?
• How much does a roof lantern cost in 2026?
• How to get planning permission for a loft conversion