Loft Conversion & Dormer Planning Permission in Brighton

Most loft conversions in Brighton, dormers included, fall under permitted development provided the added roof volume and materials stay within set limits - though the city's Regency conservation areas can change that on a specific street.

Permitted development limits

The allowance is 40 cubic metres of additional roof space for a terraced house - the norm across Hanover, North Laine and Kemp Town - or 50 cubic metres for a detached or semi-detached house. A dormer generally can't sit forward of the existing roof slope on any side facing a highway, materials should match the existing house, and side-facing windows need to be obscure-glazed.

Where it gets more complicated

Because so much of the city is terraced housing, a Party Wall Agreement with neighbours is usually needed before work starts - budget real time for this, since it commonly adds several weeks to the schedule. Inside the seafront and Kemp Town conservation areas, expect close scrutiny of how a dormer is seen from the street, and on the steep streets around Hanover and Round Hill, scaffolding access is worth planning for early.

Get it confirmed, don't assume it

A Lawful Development Certificate from Brighton & Hove City Council is a formal, low-cost confirmation that protects you if a neighbour complains or you sell the house later - worth getting even where permitted development clearly applies.