Loft extension planning in Hither Green
Whether your Hither Green loft needs planning permission depends first on volume: permitted development lets a roof addition add up to 40 cubic metres on a terrace house and up to 50 cubic metres on any other house. Go past that, or build something the rules do not cover, and you apply for planning permission through Lewisham. DrawingsDirect prepares the drawings for either route, with rear dormer permitted development drawings from £695 with no VAT to add.
Fixed fee from £495 drawings + £200 survey (£695 total) · all prices
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Start with the volume, not the style of loft
People searching for a gable loft conversion, a dormer or a general loft renovation in Hither Green usually want the same first answer: can it be built without a planning application? The first test is how much space the roof addition creates, because that is where the permitted development rules draw their line.
Under Class B of Part 1 of Schedule 2 to the General Permitted Development Order, a roof addition may add up to 40 cubic metres to the roof space of a terrace house. For any other house the allowance is up to 50 cubic metres. Work out which of the two your house is before you compare designs, because a design that fits the larger allowance can break the smaller one.
Terrace or not: why the same loft can need two different answers
The 40 and 50 cubic metre allowances are written into the order itself, and the wording separates a terrace house from every other kind. If your house is part of a terrace, the smaller figure applies to you. A neighbour in a detached or semi-detached house on the next street may be working to the larger one.
That is why a loft that looked achievable on a neighbour's house can fall outside the permitted limit on yours. Measure the volume of the proposed addition against your own figure early. If it lands over, the usual response is to reduce the design or to apply for planning permission, and the drawings differ for each.
Lewisham has 30 live conservation-area entries in the national planning data.
What Lewisham's householder figures show
For loft work that does need an application, it helps to know the local record. In the latest four quarters of government planning statistics, Lewisham, the council covering Hither Green, decided 578 householder applications, and 89% of them were granted.
On speed, 95% of householder decisions were made within eight weeks. These are borough-wide householder figures that include every kind of home improvement, not lofts alone, so read them as the background to an application and not as a forecast for yours.
What the appeal record says
If an application is refused, the applicant can appeal to the Planning Inspectorate. In its latest casework database, Lewisham has 162 householder appeals decided, and 30% of those were allowed.
That figure covers all householder development, not only loft conversions. It is a reason to take the officer's reasons for refusal seriously and to ask whether a revised scheme answers them.
Check for a conservation area before you draw anything
Lewisham has 30 live conservation-area entries in the national planning data. Whether your street sits inside a designated area is a fact to confirm on the council's own map before you commit to a design.
Checking before you design is cheaper than discovering it later.
Permitted development, and proving it with a certificate
A loft that fits within permitted development does not need a planning application, but many owners still want written proof for a future sale or a lender. A certificate of lawful development provides that. Over the last eight quarters, 722 certificates of lawful development were decided in Lewisham, so it is a well-used route.
DrawingsDirect's published starting fee for rear dormer loft conversion permitted development drawings is £695 with no VAT to add, shown on the pricing page with no form in front of it.
Choosing between a permitted development loft and an application
If your loft design stays under 40 cubic metres on a terrace house, or 50 cubic metres on any other house, permitted development is the simpler path. If the design you want is larger, the choice is between trimming it and applying, and the Lewisham householder grant rate above is the context for that decision.
Whichever you choose, the building regulations still apply to the finished loft, so plan for the structure, stairs and insulation as well as the planning side.
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, with no VAT to add, 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 |
| 50 cubic metres | GPDO 2015 Sch 2 Pt 1 Class B.1(d)(ii): roof additions may add up to 50 cubic metres to the roof space of any other house (source wording: "50 cubic metres in any other case") | www.legislation.gov.uk |
| 578 | Our analysis of MHCLG planning application statistics, table PS2 (district open data table) (released 24 Sep 2026, quarters to 2026 Q2) | www.gov.uk |
| 89% | 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 |
| 162 | Our analysis of Planning Inspectorate Casework Database (released 1 Oct 2026 (Casework Database 2609)) | www.gov.uk |
| 30% | Our analysis of Planning Inspectorate Casework Database (released 1 Oct 2026 (Casework Database 2609)) | www.gov.uk |
| 30 | 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 |
| 722 | Our analysis of MHCLG planning application statistics, table PS1 (district open data table) (released 24 Sep 2026, quarters to 2026 Q2) | www.gov.uk |
Photographs: David Hawgood (CC BY-SA 2.0).
