Planning FAQ
Do I need planning permission for a single-storey rear extension?
Standard PD limits: 3m deep (attached) or 4m (detached), under 4m high. Conservation areas and flats need full planning.
Standard PD limits: 3m deep (attached) or 4m (detached), under 4m high. Conservation areas and flats need full planning.
Not if it stays within permitted development: 3 m deep from the original rear wall on an attached house or 4 m on a detached one, up to 4 m high, and no more than 3 m high within 2 m of a boundary. Going to 6 m or 8 m is possible through prior approval at £249 over six weeks.
Depth of 3 m for a terraced or semi-detached house and 4 m for a detached one, measured from the original rear wall. Maximum height 4 m, reduced to 3 m within 2 m of a boundary. Eaves height no higher than the existing eaves. Total ground coverage of all extensions and outbuildings not exceeding 50% of the curtilage excluding the original house. Materials similar in appearance.
The extension must not be forward of any wall forming the principal elevation and fronting a highway, and must not involve a veranda, balcony or raised platform above 300 mm.
You notify the council with a description and a plan showing the extension and the adjoining properties. They consult adjoining owners for 21 days. If no adjoining owner objects, the extension may proceed; if one does, the council decides on amenity grounds alone within six weeks. The fee is £249.
It is unavailable in conservation areas and on Article 2(3) land, and the extension must be completed with the council notified of completion.
The rear wall of the house as originally built. On a Victorian terrace with a back addition, that is the back of the main house — not the back of the addition. This is the single most misunderstood point in London extension planning, and it is why so many side-return and wraparound schemes need a full application.
£548, eight weeks, with a 21-day neighbour consultation. The decisive test is usually the 45-degree rule: a line at 45 degrees from the centre of the neighbour's nearest ground-floor habitable window should not be crossed in plan or section.
Do I need planning permission for a single-storey rear extension? in a Lewisham context: London Borough of Lewisham (Lewisham Council) runs 30 conservation areas including the Blackheath Conservation Area and the Deptford High Street Conservation Area, and there is no borough-wide Article 4 direction, so permitted development generally survives outside conservation areas. That decides how do i need planning permission for a single-storey rear extension? is handled: £548 and 8 weeks for a Lewisham householder application, or £274 for the Lawful Development Certificate that records do i need planning permission for a single-storey rear extension? as lawful. The law behind do i need planning permission for a single-storey rear extension? sits in the Town and Country Planning Act 1990, the GPDO 2015 and the Building Regulations 2010.
| Depth, attached house | 3 m (6 m via prior approval) |
|---|---|
| Depth, detached house | 4 m (8 m via prior approval) |
| Maximum height | 4 m; 3 m within 2 m of a boundary |
| Prior approval | £249, 6 weeks, 21-day consultation |
| Full application | £548, 8 weeks |
| Curtilage coverage limit | 50% |
Through the larger home extension prior approval route, yes — outside conservation areas, subject to neighbour consultation.
Yes, where it projects beyond the original rear wall.
A test of whether the extension crosses a 45-degree line from the neighbour's nearest habitable window.
Pick a slot that suits you. No obligation and no sales pressure, just straight answers on your planning route.
