What you could build at CR0 9DR: the planning rules at this address, what neighbours have built and how big, planning decisions nearby, rough costs and the value an extension adds, and how to get started. In New Addington North, Croydon.
7extensions seen within 600 m in the last 10 years
0loft conversions within 600 m in the last 10 years
70.9extensions per 1,000 homes in the neighbourhood (10 years)
● work seen on energy certificates · ● application approved · ● refused · ● pending or other · ● this postcode
The rules at this address
Houses usually have permitted development rights: some rear extensions (typically up to 3 m deep for a semi or terrace, 4 m detached), loft conversions within volume limits, and porches can go ahead without planning permission. Larger single-storey rear extensions (up to 6 m / 8 m) can use the “prior approval” neighbour scheme.
Not in a conservation area (from council registers).
No Article 4 direction recorded for this postcode.
Listed buildings need listed building consent for most changes, inside and out: check the National Heritage List.
To be certain work is permitted development, apply for a lawful development certificate (about £129 for householders in England). Building regulations apply either way.
Across England and Wales, homes extended by a typical 30 m² and then resold rose about 11.1% more than similar homes nearby over the same years (124,884 resales). How extensions pay off by size, type and region.
Single-storey rear or side extension: about £2,000–£3,000 per m² (London £2,500–£4,000), plus fees and VAT
Loft conversion: about £45,000–£75,000 for a dormer; more for a mansard or hip-to-gable
Two-storey extension: about £1,800–£2,800 per m² of new floor
Garage conversion: about £15,000–£30,000
Basement: about £3,500–£5,000 per m², London mostly
Build costs are rough 2026 ranges from industry guides, not quotes. Get three quotes for your plans.
Move or improve?
The money you don't get back either way, for the same extra space in New Addington North.
Move to a home 20 m² bigger (about £418,000)
Stamp duty on the new home
£10,900
Estate agent on yours 1.2% + VAT
£4,896
Solicitors, buying and selling
£3,000
Survey
£600
Removals
£1,500
Money gone
£20,896
Extend by 20 m²
Building, plus 15% for design, planning and contingency
£57,500
Less what it adds to your home's value 60% of the local price
−£46,800
Money gone
£10,700
On these figures, extending loses about £10,196 less. Moving also changes the area, the schools and the commute; extending means months of building work and depends on planning.
Building costs vary a lot (a single-storey rear extension is often £2,000–£3,000 per m², more in London). How much space adds depends on the home and street: what extensions added to resale prices. A guide, not advice; nothing you type leaves this page.
Getting started
Look at what neighbours did. Open applications above to see drawings that were approved on similar houses, and who designed them.
Check the route: permitted development (with a lawful development certificate), prior approval for larger rear extensions, or full householder planning permission.
Get a measured survey and a designer: an architect, an architectural technologist or a designer who handles planning drawings.
Apply (householder permission is about £258 in England; councils aim to decide within 8 weeks).
Building regulations through the council's building control or an approved inspector, and party wall notices to neighbours if you build on or near the boundary.
Choose a builder: written quotes, a contract, staged payments, and check their insurance and references.
General guidance, not planning or legal advice. Fees and rules as checked in October 2026; confirm with the council.
Energy certificates: MHCLG (OGL). Planning applications: GLA Planning London Datahub. Conservation areas and Article 4: planning.data.gov.uk (OGL).
Go deeper
Extension
2016
+16 m²
69 m² → 85 m²
5 → 4
101 m
From energy certificates: an extension where a later certificate shows more floor space, a loft conversion where roof rooms appear. Certificates come with sales, lettings and some building work, so the year is when it was first seen.
Not every extension shows here. We only see building work when a new energy certificate is lodged, which happens when a home is sold, let or newly built. A loft or extension added since then won't appear, even with planning permission and building control sign-off, because those records aren't published as open data outside London. Missing work doesn't mean missing paperwork.
Rear extension
Approved
Apr 2025
25/00869/GPDO
9, Foxcombe, Cr0 9ex
Other householder work
Approved
Apr 2025
24/03456/HSE
77, The Lindens, Cr0 9el
Porch or front extension
Approved
Jan 2025
24/04049/HSE
66, Bygrove, Cr0 9dg
Rear extension
Approved
Jan 2025
24/04003/GPDO
59, Headley Drive, Cr0 0qh
Other householder work
Approved
Jan 2025
24/03477/HSE
66, Bygrove, Cr0 9dg
Rear extension
Withdrawn
Jan 2025
24/02824/HSE
77, The Lindens, Cr0 9el
Porch or front extension
Withdrawn
Aug 2024
24/02256/HSE
125, Dunley Drive, Cr0 0rj
Rear extension
Refused
Jun 2024
24/01641/GPDO
87, Headley Drive, Cr0 0ql
Side extension
Approved
Jul 2024
24/00663/HSE
13, Dunley Drive, Cr0 0rg
Porch or front extension
Approved
Mar 2024
24/00410/HSE
108, Elmside, Cr0 9dw
Rear extension
Approved
Feb 2024
23/04690/HSE
81, North Walk, Cr0 9er
Rear extension
Approved
Jan 2024
23/04285/GPDO
61, Bygrove, Cr0 9dg
Rear extension
Approved
Nov 2023
23/03616/HSE
74, Elmside, Cr0 9du
Rear extension
Approved
Jan 2024
23/03305/HSE
58, Applegarth, Cr0 9dd
Other householder work
Approved
Oct 2023
23/03228/HSE
13, Ripley Close, Cr0 0rp
Outbuilding or garden room
Approved
Aug 2023
23/02431/HSE
102, The Lindens, Cr0 9en
Other householder work
Approved
Feb 2023
23/00140/HSE
63, Headley Drive, Cr0 0qh
Rear extension
Approved
Feb 2023
23/00174/GPDO
Householder applications validated since 2023 within 600 m. The council's page has the drawings, the decision notice and who the agent or architect was. Hover a row for the description. Source: GLA Planning London Datahub.
–
88% (122)
88%
8 weeks
Basement
–
74% (57)
83%
8 weeks
Porch or front extension
–
88% (65)
81%
8 weeks
Share of decided applications approved since 2023 (number decided in brackets). Withdrawn applications aren't counted; many are withdrawn when refusal looks likely.