Kitchen Extension Planning Permission in Harrow on the Hill

Whether a kitchen extension in Harrow on the Hill needs planning permission usually comes down to size, not the fact of building one at all - most single-storey rear extensions qualify for permitted development, subject to the limits below and to Harrow on the Hill's own conservation area restrictions.

Permitted development limits

Without full planning permission, a single-storey rear extension in Harrow on the Hill is typically capped at 3m beyond the rear wall for terraced and semi-detached houses, or 4m for detached houses. Going further - up to 6m or 8m respectively - is possible via the "larger home extension" prior approval route, which means notifying neighbours through the London Borough of Harrow and clearing an objection period before building.

Height limits typically apply too - commonly around 4m maximum for a single-storey rear extension, and no higher than 4m within 2m of a boundary.

What's different in Harrow on the Hill

Where 8 conservation areas covering the Hill - over a third of all Harrow's conservation areas, among the earliest designated in England cover parts of Harrow on the Hill, permitted development rights for extensions are commonly restricted or removed entirely - materials, roofline and even window style may need to match the existing house rather than a standard modern finish. the London Borough of Harrow's planning department can confirm your specific property's status before you commit to a design.

Get it confirmed, don't assume it

Even where permitted development likely applies, a Lawful Development Certificate from the London Borough of Harrow is a formal, low-cost confirmation that protects you if a neighbour complains or you sell the house later. A builder who works regularly in Harrow on the Hill will usually have a good instinct for whether your plans qualify, but the council's confirmation is what removes doubt entirely.