Loft extension planning in Bexley
Loft extension planning in Bexley starts with whether the dormer fits permitted development: up to 40 cubic metres on a terraced house, set back 0.2 metres from the eaves. If not, the borough granted 95% of its householder decisions in the latest four quarters. Rear dormer drawings start at £695, L-shaped at £745.
Fixed fee from £495 drawings + £200 survey (£695 total) · all prices
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Choosing the dormer before the route
The shape of the dormer decides which route you take. A rear dormer at £695 is the lightest option. An L-shaped dormer at £745 covers a roof with a rear wing.
Both are tested against Class B of the permitted development order, which caps a terraced house at 40 cubic metres and requires the 0.2 metre set-back. Roofs with a hip are better suited to our hip-to-gable drawings for Bexley.
How Bexley treats householder applications
In the four quarters to mid-2026, our analysis of the MHCLG planning application statistics (table PS2) finds Bexley decided 877 householder cases and granted 95% of them. Excluding prior approvals, 100% were decided inside eight weeks, once rounded.
Those are results for all householder work, which includes extensions as well as lofts. They still describe a council that refused about one householder case in twenty. The Bexley planning permission page covers the process.
Our analysis of the MHCLG Planning Data Platform counts 31 conservation-area entries for Bexley on the national register, which may be incomplete.
Refusals and what followed
The Planning Inspectorate casework database, as analysed by us, records 157 householder appeals decided for Bexley from 2021 to 2026. 34% were allowed, so about two in three upheld the refusal.
Checking designations and certificates
Our analysis of the MHCLG Planning Data Platform counts 31 conservation-area entries for Bexley on the national register, which may be incomplete. Confirm your street on the council's map before relying on permitted development.
A permitted dormer can be confirmed with a certificate of lawful development. Our analysis of table PS1 counts 586 certificates decided by Bexley over eight quarters.
Drawings for the nearby postcodes
The borough's postcodes have their own pages: Belvedere DA17 and Sidcup DA15. To lay out the new rooms, see our Bexley floor plans. Drawings take 7 days, with free redraws until approval.
Sources
Every figure on this page, where it comes from and a link to the original.
| Figure | Source | Link |
|---|---|---|
| £695 | DrawingsDirect starting fixed fee for rear dormer loft conversion permitted development drawings, from the published price list | drawingsdirect.co.uk |
| £745 | DrawingsDirect starting fixed fee for L-shaped dormer loft conversion permitted development drawings, from the published price list | drawingsdirect.co.uk |
| 40 cubic metres | GPDO 2015 Sch 2 Pt 1 Class B.1(d)(i): roof additions may add up to 40 cubic metres to the roof space of a terrace house (source wording: "40 cubic metres in the case of a terrace house") | www.legislation.gov.uk |
| 0.2 metres | GPDO 2015 Sch 2 Pt 1 Class B.2(b): a roof enlargement must be set back not less than 0.2 metres from the eaves, measured along the roof slope (source wording: "not less than 0.2 metres from the eaves") | www.legislation.gov.uk |
| 877 | Our analysis of MHCLG planning application statistics, table PS2 (district open data table) (released 24 Sep 2026, quarters to 2026 Q2) | www.gov.uk |
| 95% | Our analysis of MHCLG planning application statistics, table PS2 (district open data table) (released 24 Sep 2026, quarters to 2026 Q2) | www.gov.uk |
| 100% | Our analysis of MHCLG planning application statistics, table PS2 (district open data table) (released 24 Sep 2026, quarters to 2026 Q2) | www.gov.uk |
| 157 | Our analysis of Planning Inspectorate Casework Database (released 1 Oct 2026 (Casework Database 2609)) | www.gov.uk |
| 34% | Our analysis of Planning Inspectorate Casework Database (released 1 Oct 2026 (Casework Database 2609)) | www.gov.uk |
| 31 | Our analysis of MHCLG Planning Data Platform conservation-area and article-4-direction datasets (bulk snapshot retrieved 14 Aug 2026) | www.planning.data.gov.uk |
| 586 | Our analysis of MHCLG planning application statistics, table PS1 (district open data table) (released 24 Sep 2026, quarters to 2026 Q2) | www.gov.uk |
Questions people ask
How do I find out if my Bexley loft conversion needs planning permission?
How much does an L-shaped dormer cost to draw in Bexley?
What share of Bexley householder applications are granted?
Photographs: David Hawgood (CC BY-SA 2.0).
