Home / Cost guides / How much does a house extension cost in Cheshire?
How much does a house extension cost in Cheshire?
In Cheshire, single-storey extensions are £1,800 to £3,000 per square metre in the 4 March 2026 guide and the extensions guide read on 30 October 2026 [S6][S7]. Two storeys are £1,000 to £2,500 per square metre in the 13 January 2026 guide and the extensions guide's at-a-glance line, prices vary by job and location, and QuoteZila does not set prices [S6][S8].
Last reviewed:An extension price is a footprint, not a slogan
Cheshire extension quotes are the price of adding a stated room onto a stated house. Soil, drains, the kitchen you might move, and the way you join the old roof all sit inside a serious quote. The Federation of Master Builders' single-storey guide of 4 March 2026 and its house extensions guide, read on 30 October 2026, put a single-storey extension at £1,800 to £3,000 per square metre [S6][S7]. Its two-storey guide of 13 January 2026 and the at-a-glance line on that extensions guide put a two-storey extension at £1,000 to £2,500 per square metre [S6][S8]. The extensions guide does not show a publication date. These are not Cheshire prices. Prices vary by the job and the location, and QuoteZila does not set prices. If the house is in the east of the county, start with Cheshire East when you need the planning authority. The west of the county is a different council. Covenants, and streets where permitted development has been switched off, are questions for that council.
The limits the Planning Portal actually prints
These rules are for houses in England, and they count the extension you want together with ones already built. The Planning Portal is explicit that the original house means the house as first built, or as it stood on 1 July 1948 if it is older than that [S1]. A previous owner's add-on still counts, even if you never built it [S1].
For every extension the Portal lists the same outer conditions. No more than half the land around the original house may be covered by extensions or other buildings [S1]. The extension cannot rise above the highest part of the existing roof, or above the existing eaves [S1]. Within two metres of a boundary, the height at the eaves cannot exceed three metres [S1]. You cannot build forward of the principal elevation, or forward of a side elevation that fronts a highway [S1]. Verandas, balconies and raised platforms are out, and so is a microwave antenna, a chimney, a flue, a soil and vent pipe, or an alteration to the existing roof, as part of this class of work [S1]. Exterior materials must look similar to the existing house [S1]. On Article 2(3) designated land, the work cannot include cladding the exterior [S1].
Side extensions have a tighter box. Past the side elevation of the original house, the extension cannot exceed four metres in height, can only be a single storey, and can only be up to half the width of the original house [S1]. On Article 2(3) land, every side extension needs a householder application [S1].
Single-storey rear extensions cannot pass the rear wall of the original house by more than four metres if the house is detached, or three metres for any other house, and they cannot exceed four metres in height [S1]. The prior-approval route, where it is available, stretches that rear limit to eight metres for a detached house and six metres otherwise [S1]. The Portal says the authority has to be told through a prior approval application [S1].
Anything over one storey must not project more than three metres beyond the rear wall, and must not sit within seven metres of the boundary opposite that rear wall [S1]. The roof pitch should match the existing house as far as practicable [S1]. An upper-floor window in a side wall must be obscure-glazed, and non-opening unless the openable part is more than 1.7 metres above the floor [S1]. Side extensions of more than one storey need a householder application, and so do rear extensions of more than one storey on Article 2(3) land [S1].
Flats, maisonettes, and many houses created through change-of-use permitted development, are outside this summary [S1]. So is a site where a condition or an Article 4 direction has removed the right [S1]. If the floor space added is over 100 square metres, the Portal says the work may also be liable for the Community Infrastructure Levy [S1]. That is a warning to check with the authority, not a fee set out as a national tariff.
A three metre rear extension sits on the non-detached rear limit. A timber frame extension and a glass extension still have to pass the same planning tests. None of those pages is a price list either.
Building regulations do not switch off because the size is modest
GOV.UK states that building regulations approval is different from planning permission, and that you might need both [S2]. The Building Regulations 2010 cover the construction and extension of buildings [S2]. The same page says you might need approval for many alterations even when they are not a new wing: windows and doors, roof coverings, a heating system, a bathroom that involves plumbing, and electrical work of certain kinds [S2]. If you cannot decide, it says check with a building control body [S2].
You do not need to get approval yourself if you use someone registered with a competent person scheme, for the work that scheme covers [S2]. An extension is still a building, not a like-for-like repair of a socket. Put the building-control route in the quote: who applies, which body, and whether their fee is inside the total.
GOV.UK: find your local council for building control. QuoteZila is not affiliated with this organisation.
Foundations, drains and the boundary
A single-storey room still needs something to stand on. How deep that goes is a site question. GOV.UK says that excavation near to and below a neighbour's foundation level is one of the things the Party Wall etc. Act 1996 covers, along with new building on or at the boundary [S3]. Cutting into a party wall is listed among the examples [S3].
The Act is not planning permission and it is not building regulations approval [S3]. Where it applies, a party wall notice is the formal step, not a text message. Read the guidance before you assume a rear kitchen on a terrace is only your affair.
Drains are the other hidden line. Moving a manhole, building over a sewer, or shifting a soil pipe can be a separate consent from the water company. Ask the water company what that consent costs, and ask each builder whether the run of drain they can see is inside their price.
Lines that make two quotes incomparable
| Line | Why two quotes diverge |
|---|---|
| Footprint and height | The Portal's metre limits are legal caps, not a tariff [S1] |
| Detached or not | Rear projection differs: four metres detached, three metres otherwise, before any prior-approval stretch [S1] |
| Foundations and the soil | Depth is a design matter. Neighbour foundations can bring in the Act [S3] |
| Joining the existing roof | Altering the existing roof is excluded from this class of permitted development [S1] |
| Kitchen, bathroom or empty shell | Plumbing and electrics are extra trades |
| Glazing and doors | Materials must look similar if you are relying on permitted development [S1] |
| Building control fee | The regulations cover extensions [S2] |
| Waste, scaffold and making good | Often the gap between a low sheet and a full one |
| VAT | Register when taxable turnover goes over £90,000 [S5] |
What to send with the enquiry
- A sketch with the projection you want, marked from the original rear wall, not from a later conservatory.
- House type, and whether an extension is already there [S1].
- Photos of the rear, the boundary, manholes and the room you would open up.
- What the new space is for. A dining area and a bathroom are different services.
- Whether you have spoken to the neighbour.
- The postcode. A crew working in Cheshire still has to reach the garden with materials.
Jobs you might post
These are examples, not taken from real job posts.
- "Semi-detached house. We want a single-storey rear room about the depth the ordinary limit allows, not the prior-approval stretch. Please include foundations, the steel if the back wall opens up, insulation, and building control. Kitchen units are not required."
- "Detached house on a corner. Please say if the side we want to build on fronts a highway, and price a single storey only if the Portal's side rules allow it. If they do not, say so rather than guessing."
- "Terrace. Rear extension for a dining table. The neighbour's kitchen is the other side of the party wall. Include the cost of finding out about a party wall notice, as its own line, and do not start digging until that is clear."
The phrase "about the depth" in the first example is a householder's description, not a measured figure from a source.
Comparing the paperwork, not the headline
Citizens Advice describes a quote as a fixed price and an estimate as a rough guess [S4]. It says the trader should not charge more than the quoted price unless you ask for extra work, you agree to extra work they have told you about, or they made a genuine mistake in the writing or the calculation [S4]. Get at least three written quotes [S4]. Be wary of a trader who will not put the quote in writing, and be cautious if one price is a lot lower: it may not be the same work [S4].
| Ask to see this | What it tells you |
|---|---|
| The projection in metres from the original rear wall | Shows they have priced your limit, not a generic box [S1] |
| A fixed total, and how long it stays open | Citizens Advice wants a fixed total, not a daily rate left open [S4] |
| Whether VAT is inside that total | Turnover over £90,000 means the business must register [S5] |
| Who applies to building control | Extensions are covered by the regulations [S2] |
| Foundations, drains and the boundary | The Act can cover excavation near a neighbour [S3] |
| What is excluded: kitchen, floor finish, decoration | The usual reason a second quote looks higher |
For insurance, Citizens Advice says ask what the trader holds, ask to see the policies, and check they do not run out before the job finishes [S4]. If there is a guarantee, ask whether it is insurance-backed [S4].
Official sources
QuoteZila is not affiliated with these organisations.
- Extension limits: Planning Portal [S1].
- Building regulations: GOV.UK, when you need approval [S2].
- Party walls: GOV.UK [S3].
- Quotes and deposits: Citizens Advice [S4].
- VAT: GOV.UK, when to register [S5].
This page is general information, not professional or legal advice. QuoteZila does not check Gas Safe, WaterSafe, NFRC, NICEIC or other registrations against the register on your behalf: look them up yourself.
Where this applies. The metre limits are the Planning Portal's account for houses in England. They are not a quote. Scotland, Wales and Northern Ireland set their own tests. A house outside England needs its own council's answer before you treat four metres or three metres as your allowance.
Ask for extension quotes
Describe the room and the town. Up to five matched local businesses can reply [QZ2]. QuoteZila is free for customers and local businesses [QZ1].
Honest status: QuoteZila is new. We're starting in Cheshire, beginning with Crewe, Nantwich and Sandbach, and growing area by area. Anyone in the UK can still post a job or register a business. How fast you get quotes depends on how many local businesses have joined near you. Businesses can register and receive jobs straight away. We don't check insurance, qualifications or registrations, so please check these yourself before you hire.
Posting a job is not open yet
Wider structural jobs sit on the builders page. New glazing may also involve glaziers. Plumbing for a new bathroom is closer to plumbers. All services lists the rest.
Questions about extension quotes
How much is a house extension in Cheshire?
The Federation of Master Builders' single-storey guide of 4 March 2026 and its house extensions guide, read on 30 October 2026, put a single-storey extension at £1,800 to £3,000 per square metre. Its two-storey guide of 13 January 2026 and the at-a-glance line on that extensions guide put a two-storey extension at £1,000 to £2,500 per square metre. Neither figure is a Cheshire price. Footprint, foundations, glazing and the approval route still change the total. Prices vary by the job and the location, and QuoteZila does not set prices.
When can a house be extended without a planning application?
The Planning Portal says many house extensions can be permitted development if the limits are met. Only half the land around the original house may be covered by extensions and other buildings. A single-storey rear extension must not go more than four metres past the rear wall of a detached house, or three metres for any other house, and must not exceed four metres in height. Flats are outside these rules.
What is the larger rear extension route?
Where the site is not Article 2(3) designated land and not a Site of Special Scientific Interest, the Planning Portal says the single-storey rear limit can rise to eight metres for a detached house, or six metres for any other house, but only with prior approval. The local planning authority has to be informed through that application. It is not an automatic right, and it is not a price.
Does an extension still need building regulations approval?
Planning and building regulations are different, and you might need both. GOV.UK says the Building Regulations 2010 cover the construction and extension of buildings. Being inside a permitted-development size does not switch that off. Ask a building control body before work starts.
Could foundations affect my neighbour?
They can. GOV.UK says the Party Wall etc. Act 1996 covers excavation near to and below the foundation level of neighbouring buildings, and new building on or at the boundary of two properties. The Act sits apart from planning permission and from building regulations approval. Where it applies, use a party wall notice.
What should I do about a deposit?
Citizens Advice suggests you try not to pay a large sum up front, that you can offer to buy the materials yourself, and that an unavoidable deposit should not go above 25%. Ask for a receipt. Also ask whether the trader charges to prepare the quote, because some do.
Does QuoteZila check builders who quote for an extension?
No. We don't check insurance, qualifications or registrations, so please check these yourself before you hire. You can report a quote or a business from your job page.
Can I ask for extension quotes on QuoteZila?
Yes. Post the footprint you have in mind, the house type and a Cheshire postcode. Up to five matched local businesses can send quotes. QuoteZila is free for customers and local businesses.
Related reading
- Roof repair cost: if the existing covering is the thing that has failed
- Plumber cost: for the services inside the new room
- Builders: the trade page for extension work
- All cost guides
Part of Cost guides. All services
Related trades
Cost guides
Related pages
- House Survey Cost: What Changes a Surveyor's Quote. What changes the cost of a house survey: the level of report, the size, age and type of home, extra specialist checks and VAT, and how to compare quotes.
- Kitchen Extension Cost: What Changes the Price. What changes the cost of a kitchen extension: size, foundations, roof and glazing, steels, the kitchen itself, planning, building control, party walls and VAT.
Sources
- QZ1: QuoteZila product fact. QuoteZila pricing line.
- QZ2: QuoteZila product fact. QuoteZila FAQ How does getting quotes work?.
- S1: Planning permission: extensions, Planning Portal. Accessed 2026-10-27. https://www.planningportal.co.uk/permission/common-projects/extensions/planning-permission/
- S2: Building regulations approval, GOV.UK. Accessed 2026-10-27. https://www.gov.uk/building-regulations-approval
- S3: Party Wall etc Act 1996 guidance, GOV.UK. Accessed 2026-10-27. https://www.gov.uk/guidance/party-wall-etc-act-1996-guidance
- S4: Before you get work done on your home, Citizens Advice. Accessed 2026-10-27. https://www.citizensadvice.org.uk/consumer/getting-home-improvements-done/before-you-get-building-work-done/
- S5: When to register for VAT, GOV.UK. Accessed 2026-10-27. https://www.gov.uk/register-for-vat
- S6: House extensions: the ultimate guide, Federation of Master Builders. Accessed 2026-10-30. https://www.fmb.org.uk/find-a-builder/ultimate-guides-to-home-renovation/house-extensions-the-ultimate-guide.html
- S7: Single-storey extension costs, Federation of Master Builders. Accessed 2026-10-30. https://www.fmb.org.uk/resource/single-storey-extension-costs-a-practical-guide-for-homeowners.html
- S8: Two-storey extension costs, Federation of Master Builders. Accessed 2026-10-30. https://www.fmb.org.uk/resource/two-storey-extension-costs.html