Home / Cost guides / What changes a single-storey extension price in Cheshire?
What changes a single-storey extension price in Cheshire?
In Cheshire, a single-storey extension still needs its own quote, while the Federation of Master Builders' single-storey guide of 4 March 2026, and its house extensions guide read on 30 October 2026, put that work at £1,800 to £3,000 per square metre [S7][S8]. Prices vary by the job and the location, and QuoteZila does not set prices.
Last reviewed:What you are asking a builder to price
Cheshire is where this guide starts, for someone comparing a single-storey extension in Crewe, Nantwich or Sandbach. A single storey extension cost is the cost of one design on one house. The Federation of Master Builders' single-storey extension guide of 4 March 2026 says the UK average is between £1,800 and £3,000 per square metre, and its house extensions guide, read on 30 October 2026, gives the same £1,800 to £3,000 per square metre [S7][S8]. That extensions guide does not show a publication date. The rate is not a Cheshire price. Prices vary by the job and the location, and QuoteZila does not set prices.
The usual pieces are the design, the foundations, the floor slab, the walls, the roof, the openings, the insulation, any moved drain, the electrics, the plaster and the floor finish, then making the garden and the existing rooms good again. A quote that names only "a rear extension" can leave half of those pieces out. Ask which of them are inside the figure and which would be extra.
Builders who cover this part of Cheshire can still price two houses differently, because the ground, the access and the specification are part of the job. Anyone in the UK can post or register.
Planning limits that sit under the price
In many cases, permitted development rights let you extend a house without a planning application, if the limits and conditions are met. If you want to go past them, the Planning Portal says a householder planning application is likely to be required [S1].
For every extension, only half the area of land around the original house can be covered by extensions or other buildings [S1]. The extension cannot be higher than the highest part of the existing roof, or higher at the eaves than the existing eaves [S1]. Where it comes within two metres of the boundary, the height at the eaves cannot exceed three metres [S1]. It cannot be built forward of the principal elevation or, where it fronts a highway, the side elevation [S1].
A single-storey rear extension cannot extend beyond the rear wall of the original house by more than four metres if the house is detached, or more than three metres for any other house. It cannot exceed four metres in height. Where the site is not Article 2(3) designated land or a Site of Special Scientific Interest, and subject to prior approval, that rear limit rises to eight metres for a detached house and six metres for any other house. The local planning authority has to be told through a prior-approval application [S1].
The original house means the house as first built, or as it stood on 1 July 1948 if it was built before that date [S1]. A previous owner's extension counts in the total enlargement. These rules are for houses, not flats or maisonettes. On Article 2(3) land, which includes a conservation area, a National Park, the Broads, a World Heritage Site and an area of outstanding natural beauty, extra limits apply, including a ban on cladding the exterior. An Article 4 direction or a planning condition can remove the rights. If the work adds over 100 square metres of floor space, it may also be liable for a Community Infrastructure Levy charge [S1].
Read the Planning Portal extension page against your own drawings. These limits do not confirm that your own sketch is permitted development.
Building regulations are a different permission
Building regulations approval is different from planning permission. You might need both [S2]. The Building Regulations 2010 cover the construction and extension of buildings. Without approval you may not have the certificates you need when you sell, and the person doing the work could be prosecuted if they do not comply [S2].
Citizens Advice says you usually need to follow building regulations if you extend an existing building, and that an extension is an example of work that cannot be carried out only under a competent person scheme. You need approval from a building control body before that work starts. You usually pay a fee when you apply, and you might pay again when the work is inspected [S3].
You can use your council's building control department or a private registered building control approver for work that is not higher-risk [S2]. Find the council for the address on GOV.UK. GOV.UK: building regulations approval. QuoteZila is not affiliated with this organisation. GOV.UK: find your local council for building control. QuoteZila is not affiliated with this organisation.
Higher-risk buildings, for the Building Safety Regulator route, are at least 7 storeys or 18 metres high and are a hospital, a care home, or contain at least two residential units [S2]. A single-storey addition to a house is a different project from that route. Still ask the building control body which application they want for your drawings.
The boundary, the drains and the neighbour
The Party Wall etc. Act 1996 is separate from planning permission and from building regulations approval. It covers new building on or at the boundary of two properties, work to an existing party wall, and excavation near to and below the foundation level of neighbouring buildings [S4].
A rear extension that sits on the boundary, or that digs below a neighbour's foundation, can fall inside that list. GOV.UK says a building owner who proposes work covered by the Act must give adjoining owners a party wall notice in the way the Act sets down. Adjoining owners can agree or disagree [S4]. Read the party wall guidance before you assume a handshake is enough.
Drains are a price line of their own. If a manhole or a run of pipe sits where the slab wants to go, the quote should say who moves it and who pays. That is a question for the builder and, where the pipe is shared, for the water company. This page does not print a drain-alteration price.
Lines that belong on the written quote
Citizens Advice says a quote is a fixed price and an estimate is a rough guess, so an estimate can end up costing more. A trader cannot 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 calculation [S3]. Try to get written quotes from at least three traders [S3]. Be cautious if one price is a lot lower: the work may not be the same work [S3].
| Line to look for | What the quote should say | If the line is missing |
|---|---|---|
| Footprint and height | Metres beyond the rear wall, and the eaves and roof height, checked against the Planning Portal limits [S1] | You cannot tell whether the design needs an application |
| Foundations and slab | Depth, concrete specification and who designs them | A shallow pad and a deep trench are different jobs |
| Walls, roof and openings | Materials, insulation, doors and windows, and whether the outside matches the house [S1] | The shell can be priced without the envelope you actually want |
| Drains and manholes | Whether any pipe moves, and who pays | The slab price can assume a clear garden |
| Electrics and heating | New circuits, lights and radiators, and who connects them | A shell quote often stops at the plaster |
| Making good and waste | Patching the existing room, and where soil and rubble go | Skip hire and redecoration appear later as extras |
| Permissions | Planning, prior approval, building control and any party wall notice, and who fills the forms | The build price can exclude the applications |
| VAT | Whether the total includes VAT at the standard rate for this kind of work [S5] | Two totals cannot be compared |
GOV.UK says VAT for most work on houses and flats by builders and similar trades is charged at the standard rate of 20% [S5]. Building a new house is listed as a case where you may not have to charge VAT, if the conditions are met [S5]. An extension is not that case on the page [S5]. A business must register for VAT when taxable turnover for the last 12 months goes over £90,000 [S6]. Ask whether the builder is registered and whether the total on the quote includes VAT [S3].
If a deposit cannot be avoided, Citizens Advice says not to agree to more than 25%, and to get a receipt [S3]. They also suggest offering to buy the materials yourself instead of handing over a deposit [S3]. Contact your buildings insurer before work starts. You might pay more for the cover during and after the work, and the insurer will probably want to know which trader you are using and what insurance that trader holds [S3].
Crewe, Nantwich and the access question
Crewe is a railway town, with Crewe station on the West Coast Main Line. Nantwich sits on the River Weaver. Neither fact sets a price. They are a reminder that the van, the muck-away and the materials have to reach the back garden.
Say, in the job, whether there is a side passage, how wide it is, and whether a skip can sit on the drive. A rear extension behind a house near the station is not the same access problem as a plot with a side gate wide enough for a digger. Do not assume the builder has seen the path. Photos of the passage, the manholes and the neighbour's wall belong in the enquiry.
Sandbach can be included in the same post if that is where the house is. The comparison is still three written quotes for the same drawing, not a town average. This page does not print one.
Jobs you might post
These are examples, not taken from real job posts.
- A four-metre rear extension on a detached house in Nantwich, with a kitchen opening, bi-fold doors, and the existing patio drain to move.
- A three-metre rear extension on a semi-detached house in Crewe, single storey, with a side passage too narrow for a pallet.
- Prior-approval paperwork and a build for a longer rear extension, once the council has said which route applies.
- Foundations, slab and shell only, with the homeowner supplying the kitchen separately, so the builder's quote stops at a stated line.
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A job can be sent to up to five matched local businesses [QZ2].
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Questions people ask
How much does a single-storey extension cost per square metre?
The Federation of Master Builders' single-storey guide of 4 March 2026 says the UK average is between £1,800 and £3,000 per square metre, and its house extensions guide, read on 30 October 2026, gives the same £1,800 to £3,000 band. The March guide says the figure depends on location and the quality of the work. It is not a Cheshire price and not a price for one drawing. Prices vary by the job and the location, and QuoteZila does not set prices.
Does QuoteZila check the businesses?
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.
Does a single-storey rear extension always need a planning application?
Not always. The Planning Portal sets rear limits of four metres beyond the original rear wall for a detached house and three metres for any other house, with a larger prior-approval route of eight metres or six metres where that route is open. Flats are outside these householder rights, and Article 4 or a planning condition can remove them. Ask the council about your own house before you treat a sketch as allowed.
Is building regulations approval the same decision as planning permission?
No. GOV.UK says building regulations approval is different from planning permission and that you might need both. The Building Regulations 2010 cover the construction and extension of buildings. Citizens Advice gives an extension as an example of work that is not left only to a competent person scheme, so a building control body is involved before the job starts.
Why can two single-storey quotes look far apart?
Citizens Advice says a written quote should include a breakdown of the work and the materials. Be cautious if a price is a lot lower than other quotes: it might mean the trader does not have the right skills or experience, or is not being honest, and it could also mean they are not quoting for exactly the same work. Line the quotes up on paper before you decide.
What should I do about a deposit on an extension?
Citizens Advice says not to pay everything up front. If a deposit cannot be avoided, do not agree to more than 25%, and get a receipt. Offering to buy the materials yourself is the alternative they suggest, so you still own those materials if the job stalls. Stage payments, written into the contract, keep the rest of the money tied to finished parts of the build.
Does VAT apply to a single-storey extension?
GOV.UK says VAT for most work on houses and flats by builders and similar trades is charged at the standard rate of 20%, with exceptions that include building a new house. An extension of an existing house is not described there as a new house. Ask the builder whether the quoted total includes VAT, which is one of the items Citizens Advice says a written quote should state.
Where do I find the council that covers a Cheshire address?
GOV.UK has a page for finding your local council, which is the route to the planning department and to local authority building control. A private registered building control approver is the other route GOV.UK describes for work that is not a higher-risk building. Take the address of the house, not a town name alone, because the council boundary is what decides who you apply to.
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Related pages
- Soakaway Drains in Cheshire: What to Ask. What to ask about a soakaway drain in Cheshire before anyone digs. This guide prints no pound figure. It points at planning and building rules, not a tariff.
- Structural Engineer Fees: What Changes the Cost. What moves a structural engineer's fee: a site visit or calculations only, wall removal, extensions, cracks, drawings for building control and revisits.
Sources
- QZ1: QuoteZila product fact. QuoteZila pricing line.
- QZ2: QuoteZila product fact. QuoteZila matching cap.
- S1: Planning permission: extensions, Planning Portal. Accessed 2026-10-26. https://www.planningportal.co.uk/permission/common-projects/extensions/planning-permission
- S2: Building regulations approval, GOV.UK. Accessed 2026-10-26. https://www.gov.uk/building-regulations-approval
- S3: Before you get work done on your home, Citizens Advice. Accessed 2026-10-26. https://www.citizensadvice.org.uk/consumer/getting-home-improvements-done/before-you-get-building-work-done/
- S4: Party Wall etc. Act 1996 guidance, GOV.UK. Accessed 2026-10-26. https://www.gov.uk/guidance/party-wall-etc-act-1996-guidance
- S5: VAT for builders: houses and flats, GOV.UK. Accessed 2026-10-26. https://www.gov.uk/vat-builders
- S6: Register for VAT, GOV.UK. Accessed 2026-10-26. https://www.gov.uk/register-for-vat
- 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: 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