Rear Extension London — What to Prepare
Updated: Oct 8
Rear extension in London — clarifying your brief before you speak to a builder
A rear extension can create more kitchen-diner space or improve the connection to the garden. This guide helps you prepare a garden-facing project brief, including access, neighbours and layout decisions. Use it alongside our broader house extension and renovation project guide.
THRC (The Home Refurbishment Company) works with Greater London homeowners from 3 Shortlands, Hammersmith, London W6 8DA. A clear brief helps you discuss drawings, planning checks and a project-specific quote.
Why “rear” is a useful brief
A rear extension often means opening the back of a terrace or semi to the garden: more daylight, a kitchen-diner, and a doorset that makes outdoor space feel usable. Writing “rear” into your brief helps a builder or designer ask the right questions early — garden depth, neighbouring windows, drainage runs, and how materials reach the rear of the plot.
This page is for homeowners who already know the growth is likely at the back of the house, not a vague “we might extend somewhere”. If you are still comparing side return, wrap-around or wider renovation options, start with the parent guide and come back here once rear is the clear direction.
Parent guide: house extension / home renovation London project brief.
Permitted development vs planning (plain English — not legal advice)
National permitted development rules often allow limited single-storey rear depths that differ for terraced and semi-detached houses versus detached houses. Height, eaves, materials and whether the house is in a conservation area, covered by an Article 4 direction, or listed can change the path entirely. Larger Home Extension prior approval is another route some homeowners explore for deeper single-storey rears — again, confirm with your council.
None of this replaces a planning check for your address. Treat blog summaries as prompts for what to ask, not as a green light. Building Regulations still apply to structure, insulation, fire, drainage and electrics even when planning permission is not required.
Neighbours, Party Wall and access
On terraces and semis, shared walls and nearby foundations often bring Party Wall considerations. Garden access for skips and materials can be as important as the drawings themselves — especially where there is no side alley. Living through the works is another early question: temporary kitchen arrangements, dust routes and how long the rear of the house will be opened up.
Include neighbours, access and living arrangements in your first note so a site visit stays practical. Ask a party wall surveyor about any notices, agreements and fees that may apply.
Design questions that improve your builder conversation
Before you compare quotes, record your priorities and the decisions still to be made:
Open-plan kitchen-diner versus retaining a separate room.
Roof form — flat, pitched or with a roof lantern — and how that affects light to neighbouring rooms.
Bi-fold, sliding or conventional doors to the garden.
Drainage, building over drains, and matching brick or render to the existing house.
Whether the kitchen moves into the extension or stays in place while the rear opens up.
Reuse a structured list with our builder quote checklist so apples-to-apples conversations are easier.
Rear extension as part of a wider refurb
Many rear projects are really kitchen and utility renovations with a new envelope. If electrics, flooring and finishes through the ground floor will change at the same time, say so in the brief. Phasing with a loft conversion later is also common — keep those conversations linked but distinct.
Frequently asked questions
Is a rear extension always permitted development in London?
Not always. Depth, height, location and local restrictions matter. Confirm with your local planning authority for your address.
Do I need a Party Wall agreement?
Often on terraces and semis where work affects shared walls or nearby foundations. Take advice early from a party wall surveyor.
How is this different from your house extension guide?
This page focuses on rear / garden-facing projects. The parent guide covers house extensions and renovation briefs more broadly — see the extension project brief.
How do I prepare for a quote?
Use the quote checklist plus the design questions above.
How THRC usually starts a conversation
For a rear extension conversation, share your postcode, garden photos, notes on neighbours and access, and whether the kitchen will move. An optional site visit can follow from our Hammersmith base where it helps.
Primary next step: contact THRC.
Useful preparation: London builder quote checklist.
020 3633 8086 · sales@thehomerefurbishmentcompany.co.uk
Contact THRC
The Home Refurbishment Company (THRC Construction)
3 Shortlands, Hammersmith, London W6 8DA
Phone: 020 3633 8086
Enquiries: Contact
Comments