Conservation area planning in Harrow

Harrow has 29 designated conservation areas, including Harrow on the Hill, Pinner Village, Stanmore, Harrow Weald.

Any external alteration visible from a public space typically requires full planning permission inside a conservation area: roof additions, dormers, replacement windows, rendering, hardstanding, and demolition. Internal works generally do not, unless the property is also listed.

Yes — every application inside a conservation area requires a Heritage Statement. It must address the conservation area character appraisal, identify heritage assets, and explain how the design preserves or enhances character. We prepare this as part of every conservation-area application.

Rear mansards and dormers are routinely approved in many London conservation areas where the design matches the terrace's existing roofscape — particularly in Hackney, Islington, Tower Hamlets, Lambeth and Southwark. Front-facing dormers are almost universally refused.

Harrow Council statutory determination is 8 weeks for householder applications. Conservation officer consultation adds 2–3 weeks in practice. Expect 11–14 weeks from validation to decision.