What you could build at DA1 4NA: 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 Crayford, Bexley.
26extensions seen within 600 m in the last 10 years
11loft conversions within 600 m in the last 10 years
63.1extensions 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 Crayford.
Move to a home 20 m² bigger (about £518,000)
Stamp duty on the new home
£15,900
Estate agent on yours 1.2% + VAT
£5,976
Solicitors, buying and selling
£3,000
Survey
£600
Removals
£1,500
Money gone
£26,976
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
−£61,800
Money gone
−£4,300
On these figures, extending loses about £31,276 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.
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.
Other householder work
Approved
Apr 2026
26/00336/FUL
21, Barnes Cray Road, Da1 4nr
Rear extension
Not needed / lawful
Mar 2026
26/00271/GPDE
35, Crayford Road, Da1 4an
Rear extension
Approved
Mar 2026
26/00302/GPDE
21, Barnes Cray Road, Da1 4nr
Two-storey extension
Approved
Apr 2026
26/00270/FUL
128, Crayford Way, Da1 4lf
Rear extension
Approved
Mar 2026
26/00255/LDCP
21, Russell Close, Da1 4pu
Loft or dormer
Approved
Mar 2026
26/00256/LDCP
7, Russell Close, Da1 4pu
Rear extension
Approved
Feb 2026
26/00017/LDCP
21, Russell Close, Da1 4pu
Loft or dormer
Approved
Jan 2026
25/02413/LDCP
7, Russell Close, Da1 4pu
Rear extension
Refused
Dec 2025
25/02407/GPDE
21, Medway Road, Da1 4pw
Rear extension
Not needed / lawful
Dec 2025
25/02181/GPDE
191, Maiden Lane, Da1 4pt
Rear extension
Not needed / lawful
Oct 2025
25/01940/GPDE
179, Iron Mill Lane, Da1 4pf
Side extension
Approved
Sept 2025
25/01467/FUL
239, Crayford Way, Da1 4ls
Loft or dormer
Approved
Jul 2025
25/01263/LDCP
188, Iron Mill Lane, Da1 4pe
Loft or dormer
Approved
Jul 2025
25/01174/LDCP
179, Iron Mill Lane, Da1 4pf
Rear extension
Not needed / lawful
Jun 2025
25/00898/GPDE
179, Iron Mill Lane, Da1 4pf
Loft or dormer
Approved
Jun 2025
25/00897/LDCP
28, Beech Walk, Da1 4np
Rear extension
Refused
Jun 2025
25/00622/GPDE
21, Russell Close, Da1 4pu
Rear extension
Not needed / lawful
Apr 2025
25/00328/GPDE
187, Iron Mill Lane, Da1 4pf
Rear extension
Not needed / lawful
Mar 2025
25/00171/GPDE
187, Iron Mill Lane, Da1 4pf
Loft or dormer
Approved
Mar 2025
25/00189/LDCP
11, Mayplace Avenue, Da1 4py
Rear extension
Not needed / lawful
Feb 2025
25/00004/GPDE
45, Mayplace Avenue, Da1 4pq
Rear extension
Refused
Dec 2024
24/02752/LDCP
67, Whitehill Road, Da1 4ab
Loft or dormer
Approved
Nov 2024
24/02301/LDCP
67, Whitehill Road, Da1 4ab
Loft or dormer
Under consideration
–
4/02301/LDCP
208, Crayford Way, Da1 4lr
Rear extension
Not needed / lawful
Sept 2024
24/02078/GPDE
30, Mayplace Avenue, Da1 4pz
Rear extension
Approved
Aug 2024
24/01938/LDCP
71, Whitehill Road, Da1 4ab
Loft or dormer
Approved
Jul 2024
24/01591/LDCP
71, Whitehill Road, Da1 4ab
Loft or dormer
Refused
May 2024
24/00703/LDCP
8, Gable Close, Da1 4ad
Rear extension
Not needed / lawful
Sept 2023
23/01781/GPDE
26, Whitehill Road, Da1 4aa
Loft or dormer
Approved
Aug 2023
23/01602/LDCP
8, Gable Close, Da1 4ad
Rear extension
Refused
Jul 2023
23/01257/GPDE
27, Barnes Cray Road, Da1 4nr
Outbuilding or garden room
Approved
Mar 2023
23/00092/LDCP
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.
81% (67)
88%
8 weeks
Basement
–
–
83%
9 weeks
Porch or front extension
–
81% (16)
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.