Loft conversion in Hillingdon
Do you need planning permission for a loft conversion in Hillingdon? Here is what the permitted development rules say, how London Borough of Hillingdon’s designations change them, and what decides an application, grounded in the official guidance and quoted verbatim.
Do you need planning permission for a loft conversion in Hillingdon?
Rear dormers and roof enlargements are normally permitted development under Class B, within volume limits, but Class B rights do not apply on article 2(3) land, which includes every conservation area. In Hillingdon this matters: the borough has 42 conservation areas and 150 Article 4 directions, and inside those the permitted development route narrows or is removed, so a loft conversion can need a full application where it would not two streets away.
The starting point
Rear dormers and roof enlargements are normally permitted development under Class B, within volume limits, but Class B rights do not apply on article 2(3) land, which includes every conservation area.
“This provides permitted development rights for the enlargement of a house consisting of an addition or alteration to its roof.”PD technical guidance, Class B · full text in the library → · official source →
How Hillingdon’s designations apply
| Designation in Hillingdon | Published |
|---|---|
| Conservation areas | 42 |
| Article 4 directions (PD removed) | 150 |
| Listed building outlines | 441 |
Because loft conversion depends on permitted development rights restricted on article 2(3) land, the conservation areas above are decisive: inside one, expect to need a full application. Counts are read live from planning.data.gov.uk; your report checks them against your exact address.
What Hillingdon weighs
Inside a conservation area the dormer is judged on how it treats the roofscape: proportion, siting on the slope, the ridge line, and materials that defer to the original roof.
As a London borough, London Borough of Hillingdon also decides against the London Plan 2021 (the strategic policy layer for all 33 boroughs), alongside national policy and its own Local Plan.
See a loft conversion in a real report
Seven designations and the toughest approval rate in this set: 65% of 142 nearby loft decisions, the case for designing to the rules first.
Get a planning report for your Hillingdon address
A Planning Policy report reads the designations on your exact Hillingdon address, quotes the London Borough of Hillingdon and national policies that apply to a loft conversion, and (on Pro) shows decided applications nearby with outcomes.