For extension builders
Extension builders: get found by homeowners planning an extension, when our map opens in your area
Sign-up for extension builders opens soon. Listing will be free while we build the map, with at least 30 days’ notice before any charge.
Many homeowners price the job on Estiquote before they ask for quotes. When our map opens in their area, they’ll search it for “an extension” and see the extension builders who cover it.
Homeowners see £63,500 to £78,000 for a 25 m² single storey rear extension before they ask you. Building work, mid-range finish, UK average outside London, including VAT, prices reviewed 25 September 2026. The cost guide.
Firm sign-up opens soon. Email support@estiquote.co.uk with your firm's name and trade, and we'll tell you the day it opens.
What homeowners see before they ask you
| Job | Building work, UK average | Building work, London |
|---|---|---|
| House extension: Single-storey rear, 25 m² | £63,500 to £78,000 | £86,000 to £105,000 |
| House extension: Double-storey, 40 m² | £91,000 to £115,000 | £123,000 to £156,000 |
| House extension: Wraparound or side return, 30 m² | £83,000 to £104,000 | £112,000 to £141,000 |
| Region | Building work |
|---|---|
| UK average (outside London) | £63,500 to £78,000 |
| London | £86,000 to £105,000 |
| South East | £73,000 to £89,500 |
| East of England | £68,000 to £83,500 |
| South West | £66,000 to £81,000 |
| West Midlands | £61,500 to £75,500 |
| East Midlands | £60,500 to £74,000 |
| Scotland | £60,500 to £74,000 |
| North West | £59,000 to £72,500 |
| Yorkshire and the Humber | £58,500 to £72,000 |
| Wales | £57,000 to £70,000 |
| North East | £56,000 to £68,500 |
| Northern Ireland | £52,000 to £64,000 |
| Fee | Typical range |
|---|---|
| Measured survey | £600 to £1,800 |
| Building regulations drawings | £2,100 to £3,700 |
| Planning drawings (only if needed) | £1,300 to £2,400 |
| Structural engineer | £870 to £2,300 |
| Building control (council, full plans) | £740 to £1,000 |
| Householder planning application (England) (only if needed) | £548 |
| Prior approval for a larger home extension (England) (only if needed) | £249 |
| Party wall surveyor (per neighbour, one surveyor agreed by both sides) (only if needed) | £1,100 to £1,800 |
What homeowners ask extension builders
With what our guides tell them. Answer these in your quote, and later on your listing.
Do I need planning permission?
Many single storey rear extensions in England are permitted development, within size limits, and homeowners read those rules in our extension cost guide before they ask you. Almost every extension needs building regulations approval; a small conservatory can be exempt if it meets the conditions (Planning Portal).
What will the fees come to on top of the building work?
Our guide shows a measured survey, drawings, a structural engineer and building control separately: about £4,300 to £8,800 for a 25 m² single storey extension, including VAT. Say in your quote which of these your price covers, so homeowners compare like with like.
Will my neighbours need a party wall agreement?
In England and Wales, building on the boundary, cutting into a shared wall or digging foundations close to a neighbour’s means giving notice to each neighbour affected. One party wall surveyor agreed by both sides costs about £1,100 to £1,800 for each neighbour, including VAT.
How do I compare two extension quotes?
Homeowners use our extension quote guide and the checklist below. Quotes set out in the same sections are the easiest to compare, and the easiest to choose.
What homeowners will ask you to confirm
From the checklist in our house extension guide:
- Design and investigations: Drawings, measured survey, structural calculations and any trial holes (small holes dug to check the ground before the foundations are designed).
- Permissions: Planning (if needed), building control and party wall agreements.
- Site setup: Access, protection of the existing house, demolition, skips and waste.
- Groundworks and drains: Groundworks (digging out and the foundations), ground conditions and any drain diversions (moving a drain that runs where the extension will go).
- Structure and envelope: The envelope is everything that keeps the weather out: walls, steel beam, roof, insulation, windows and doors.
- Services: Heating, electrics, plumbing, ventilation and changes to existing systems.
- Fixtures and finishes: Kitchen, flooring, joinery (doors, skirting and other woodwork), lighting and decoration.
- External work: Steps, paving, drainage outside doors and garden reinstatement.
What we’ll check before extension builders appear
- Companies House, if you’re a limited company or LLP: we’ll check the company is active.
- Only if you take waste away: Waste carrier registration. The law and the registers
- Who runs the business: an ID check, or a code letter for a company’s director.
Badges you can add (not needed to appear): TrustMark and Federation of Master Builders, and insurance.
Your listing will say, for example: Checked by Estiquote on 30 October 2026:
If you’re a limited company
- Active company at Companies House
If you’re a sole trader
- Sole trader: business details checked by Estiquote
How to list
When sign-up opens for extension builders, have ready your company number if you’re a limited company, your waste carrier registration number if you take waste away. Then you’ll create your account and send your profile for checks; we’ll usually reply within 5 working days.
Homeowners will choose up to 3 firms by name, and reviews will come only from real jobs, checked by a person: how quote requests and reviews will work.
Firm sign-up opens soon. Email support@estiquote.co.uk with your firm's name and trade, and we'll tell you the day it opens.
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