Two Victorian terraced houses on a London street, one painted white and one in yellow stock brick, with bay windows
Floor plan drawings, pencil sketches of a house, a scale rule and a protractor spread across a desk
Photo: Tima Miroshnichenko / Pexels

House extension plans · London Borough of Bromley

House extension plans in Bromley, £795 fixed

Bromley's Local Plan Policy 8 normally requires a 1 metre gap to the side boundary, for the full height and length of any extension of two storeys or more. Policy 51 caps extensions to houses in the Green Belt and on Metropolitan Open Land at a 10% increase in floor area, measured externally.

Planning drawings£795
Building regs£695
Council fee£548
Get your fixed feeFFP-01 · Rev A
Our fixed fee£795
Council fee, paid to your council£548
Our fee + council fee£1,343
CoverageAll 33 boroughs

Householder application fee, paid to your council at submission.

Plus the Planning Portal's own charge if the application goes through the Portal: up to £149 including VAT, depending on the application type, and some types have none (source).

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Boroughs33/33
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The back of a house extension at shell stage, with a large glazed opening, blockwork walls and a scaffold tower
An extension at shell stage: the opening, the blockwork and the beam above it are what the building regulations drawings describe. Photo: Brett Jordan / Pexels.

What Bromley Council asks of a house extension

From the council's Bromley Local Plan, Policies 6, 7, 8 and 51 (adopted January 2019).

  • Policy 8 (Side Space): for a proposal of two or more storeys, including an extension, the council will normally require a minimum 1 metre space from the side boundary to be retained for the full height and length of the building, or a more generous side space where higher standards of separation already exist in the area. (source, checked 25 October 2026)
  • Policy 6 (Residential Extensions): the scale, form and materials should respect or complement the host dwelling and be compatible with the surrounding area, and gaps between buildings should be maintained where they contribute to the character of the area. (source, checked 25 October 2026)
  • The supporting text to Policy 6 asks for a pitched roof where possible, and says flat-roofed side extensions of two or more storeys to dwellings of traditional roof design will normally be resisted unless well set back from the building line and unobtrusive. (source, checked 25 October 2026)
  • Policy 7 (Accommodation for Family Members): an extension for additional family members must not be severable from the main dwelling-house, must be in keeping with the design and scale of the dwelling, and must be accessed through the original dwelling. (source, checked 25 October 2026)
  • Policy 51: extensions or alterations to dwellinghouses in the Green Belt or on Metropolitan Open Land are permitted only if the net increase in floor area over the original dwellinghouse is no more than 10%, measured externally, and the size, siting, materials and design do not harm visual amenities or the open character; extensions to converted or replacement dwellings will not normally be permitted. (source, checked 25 October 2026)

What Bromley house extension drawings have to show

Bromley's best-known rule is on the plans before anything else: the 1 metre side space. On a two-storey side extension the block plan and the ground and first floor plans dimension the gap to the boundary at full height and for the full length of the building, and where the street already has wider gaps the drawings show the pattern of those gaps so the extension can be judged against them. A flat-roofed two-storey side extension on a traditional pitched-roof house is not drawn unless it is well set back from the building line.

In the Green Belt or on Metropolitan Open Land the drawings carry a floor area table: the original dwelling as it stood on 1 July 1948 or as first built, any earlier extensions, and the proposal, all measured externally, against the 10% cap of Policy 51. Bromley's validation checklist makes a roof plan mandatory for any first-floor or two-storey extension and asks for a biodiversity net gain exemption statement with every application; Certificate B is needed if the extension crosses the neighbour's boundary.

Permitted development · Class A

How far a single-storey rear extension can go before it needs more than a drawing

Terraced or semi-detached

Existing houseNo applicationPrior approvalPlanning application3 m6 mDepth beyond the original rear wall

Detached

Existing houseNo applicationPrior approvalPlanning application4 m8 mDepth beyond the original rear wall

Height, side view

HouseBoundary2 m4 m maxoverall height3 m eaveswithin 2 m of boundary
Source: GPDO 2015, Schedule 2, Part 1, Class A: A.1(f) (3 m, or 4 m if detached; 4 m high), A.1(g) (6 m, or 8 m if detached; not on article 2(3) land such as conservation areas, nor on a site of special scientific interest), A.1(i) (eaves over 3 m within 2 m of a boundary) and the prior approval procedure in A.4. Terraced and semi-detached houses are the “any other dwellinghouse” case. Other conditions still apply: check the permission section and run the checker.
PS2 · at a glance

Bromley: 1,609 householder decisions

Bromley
Approvals, prior approvals included78.6%

1,264 of 1,609 granted. London: 85.8%.

Decided within 8 weeks90.2%

1,063 of 1,179 applications, prior approvals excluded.

Source: MHCLG PS2, 1 July 2025 to 30 June 2026. Dark tick: London.
A bright kitchen with white cabinets, a stainless steel range cooker and extractor hood, and a window over the sink
A kitchen in a rear extension: the wide opening into it from the old house is carried by a beam. Photo: Curtis Adams / Pexels.

What it costs in Bromley

  • Planning drawings: £795, plus £548 to Bromley Council.
  • Building regulations drawings: £695.

House extension plans across London · Bromley planning rules · every price

Answers

Bromley house extension questions

How close can a two-storey side extension get to the boundary in Bromley?
Policy 8 of the Bromley Local Plan says the council will normally require a minimum 1 metre space from the side boundary, kept for the full height and length of the building. Where the surrounding area already has wider gaps, a more generous side space is expected. Single-storey side extensions are not caught by this policy.
What is the extension limit for a Bromley house in the Green Belt?
Policy 51 allows extensions to houses in the Green Belt or on Metropolitan Open Land only if the net increase in floor area over the original dwellinghouse is no more than 10%, measured externally. The original dwelling is the house as it stood on 1 July 1948, or as first built if later. The design must also not harm the open character.
Can I build a granny annexe extension in Bromley?
Policy 7 supports an extension for family members if it cannot be severed from the main house, is in keeping with its design and scale, and is reached through the original dwelling. That rules out a separate front door or a self-contained unit that could later be let. Our drawings show the internal link between the two parts.

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Total, planning application£795
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