Do you need planning permission for a porch?

Development is not permitted by Class D if ... (b) the ground area (measured externally) of the structure would exceed 3 square metres; (c) any part of the structure would be more than 3 metres above ground level ... (d) any part of the structure would be within 2 metres of any boundary of the curtilage of the dwellinghouse with a highway

Measuring a porch

Area. The 3 square metres is measured externally, so it includes the thickness of the porch walls. A porch 1.5 metres by 2.0 metres outside is exactly 3.0 square metres and qualifies. One 1.8 metres by 1.8 metres outside is 3.24 square metres and does not, even though the floor inside may be under 3 square metres.

Height. Measured from ground level, which is the surface of the ground next to the porch or, on a slope, its highest part (article 2(2)). The 3 metres includes the roof.

Road boundary. No part may be within 2 metres of a boundary with a highway. For Part 1 a highway includes an unadopted street or a private way (paragraph I), and the technical guidance includes public footpaths. So a porch projecting 1.2 metres from the front wall needs a front garden at least 3.2 metres deep to qualify.

When it is not a porch

Class D covers a porch outside an external door. A bigger front addition, or a porch built as part of a front extension, is an enlargement under Class A, and Class A allows no enlargement beyond the principal elevation (A.1(e)). Anything at the front beyond the Class D limits therefore needs planning permission. The limits on side extensions are in side and wraparound extensions.

Listed buildings and Article 4

A porch on a listed building needs listed building consent if it affects the building's character (section 7 of the Planning (Listed Buildings and Conservation Areas) Act 1990). An Article 4 direction can withdraw Class D rights, so check with the council before you build.

Building Regulations

A porch added at ground level with a floor area of no more than 30 square metres is exempt from the Building Regulations, provided its glazing meets the safety glazing requirements (Schedule 2, Class 7 of the Building Regulations 2010). The Planning Portal adds two conditions: the front door between the house and the porch must stay in place, and the porch must not make level or ramped access worse. The 30 square metre figure is separate from the 3 square metre planning limit.

What this means for you

Draw the porch with its outside dimensions, measure the distance from its front face to the road boundary, and check for an Article 4 direction. The permitted development checker runs all three checks.

Getting certainty

A porch within the limits needs no application. If you want written confirmation, a lawful development certificate for proposed works gives it. From 1 April 2026 the fee for householder works is £274, and the council has 8 weeks to decide.