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How much does a glass extension cost in Cheshire?
In Cheshire, a glass extension price depends on whether the new room stays separated from the house and on the structure, the glass and the base. Ask the quote to name that split before you compare totals.
Last reviewed:Two glass rooms that should not share a price
In Cheshire, "glass extension" covers at least two jobs. One is a conservatory that stays cut off from the house by walls and doors of external quality. The other is a glass room that becomes part of the kitchen, with the old back wall opened up. They can look alike in a brochure and sit in different regulatory boxes. No figure is printed, because we could not find two dated public sources that agree on one. Ask the council that covers the address, with a sketch, rather than copying a neighbour's glass room.
Planning: the Portal files a conservatory with other extensions
The Planning Portal says that if you want to add a conservatory to a house, this falls within the same set of planning rules as any other home extension [S1]. Permitted development can allow the work when the limitations and conditions are met. If you exceed them, a householder application is the likely next step [S1]. The rules apply to the new work plus any previous enlargement [S1]. They apply to houses, not to flats and maisonettes, and not 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]. Check that rather than assuming a small glass box is automatically clear. The metre-by-metre tests (rear projection, height, boundaries, appearance) are the extension tests. Read them on the Portal's extensions page before you treat a show-home as permitted. The house extension guide points at the same limits. Read those metre tests there, and ask the council with a sketch of the glass room.
Materials and the link to the old roof still matter. A glass box that changes the existing roof, or that sits forward of the principal elevation, is outside the casual reading of "it's only a conservatory". Ask the council with a sketch.
The building-regulations exemption is a list, not a mood
Building regulations will generally apply if you want to build an extension [S2]. Conservatories are the exception the Planning Portal describes, and only when all of the following are true [S2]:
- Built at ground level and less than 30 square metres in floor area.
- Separated from the house by external-quality walls, doors or windows.
- An independent heating system, with separate temperature and on/off controls.
- Glazing, and any fixed electrical installations, comply with the applicable requirements.
- Single storey.
The Portal also advises you not to build a conservatory where it will restrict ladder access to windows serving rooms in a roof or loft conversion, particularly if those windows are for escape or rescue if there is a fire [S2]. That is a siting warning, not a price.
A new structural opening between the conservatory and the house requires building regulations approval even if the conservatory itself is exempt [S2]. An open-plan glass kitchen fails the separation test in the list above. Call it an extension, budget for approval, and do not remove the lintel or the back wall as a weekend job.
GOV.UK: find your local council for building control. QuoteZila is not affiliated with this organisation.
Glass, wiring and who does which part
Glazing has to comply where the exemption still demands it, and fixed electrics have to comply too [S2]. Separately, the Planning Portal's electrics guidance says work in a home or garden in England and Wales must comply with the building regulations [S3]. It says it is the right route to use an installer registered with a competent person scheme, who can self-certify [S3]. Notifiable jobs include a new circuit, a new consumer unit, and alterations in special locations, which in England means the spaces around baths and showers [S3]. Most other alterations outside those locations are not notifiable, but they still have to comply [S3].
A glass room with new sockets, underfloor heating or a new circuit is electrical work. Hire a registered electrician for that part. Do not wire it yourself.
Electrical Safety First: find a registered electrician; NICEIC; NAPIT. QuoteZila is not affiliated with this organisation.
Fixed wiring in the new room should be done by someone listed on the Electrical Safety First register search. You can also look at NICEIC and NAPIT. A glazing firm that only supplies the units is not that person unless the quote says they are registered.
The frame and the base are the builder's or the glazier's lines. Ask which firm is responsible for the dwarf wall or the ring beam, and which firm is only supplying sealed units. A quote that says "glass extension" and does not split those lines cannot be compared with one that does.
What the paperwork should separate
| Line | Why it is its own question |
|---|---|
| Separated conservatory or open to the house | Exemption depends on external-quality separation [S2] |
| Floor area | Exemption looks at under 30 square metres, at ground level, single storey [S2] |
| Base and foundations | Not described by the glass specification |
| Frame and sealed units | The visible part, often ordered before the base is agreed |
| Structural opening | Needs approval even if the box would have been exempt [S2] |
| Heating | Exemption expects an independent system with its own controls [S2] |
| Electrics | Fixed installations must comply [S2] [S3] |
| Building control fee | Generally applies to an extension [S2] |
| VAT | Register when taxable turnover goes over £90,000 [S5] |
What to send so the quotes match
- Say "separated by the existing back doors" or "back wall opened up". Do not leave it implied.
- A rough floor area, and whether the site is level.
- Photos of the rear elevation and of any loft windows the new roof might block [S2].
- Whether you want heating tied to the house boiler or kept separate.
- The postcode.
Jobs you might post
These are examples, not taken from real job posts.
- "Semi in Sandbach. We want a ground-floor glass room under 30 square metres, still separated by the existing external doors, with its own heater. Please confirm you are pricing an exempt conservatory and list anything that would stop the exemption."
- "Detached house. We want the back wall opened so the glass room is part of the kitchen. Please price it as an extension that needs building regulations approval, including the new opening, and do not describe it as an exempt conservatory."
- "Terrace in Cheshire. Glass roof on a small rear room. Please say how you will keep ladder access to the loft window, and price scaffold separately."
Comparing glass quotes
Citizens Advice says get the quote in writing, because a quote is a fixed price and an estimate is a rough guess [S4]. Try for at least three traders [S4]. Be wary if someone will not write it down, and be cautious if one figure is a lot lower [S4]. Ask to see insurance that covers the period of the work [S4]. If a guarantee is offered on the units, ask whether it is insurance-backed [S4].
Base, frame and the order they are bought in
Glass is often the line a household looks at first, and it is often ordered before the base is designed. Ask which happens first. A frame that arrives for a slab that has not been checked against the floor level of the house will sit wrong, and the fix is rarely free. Get the base, the structural opening and the frame in one written description before anyone pays for sealed units.
Cleaning and replacement of a unit years later are not the build price. Ask who can source a matching unit, and whether that sits inside any insurance-backed guarantee or outside it [S4].
Official pages
QuoteZila is not affiliated with these organisations.
- Planning, conservatories: Planning Portal [S1].
- Building regulations, conservatories: Planning Portal [S2].
- Electrics: Planning Portal [S3].
- Quotes and deposits: Citizens Advice [S4].
- VAT: GOV.UK [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 exemption list is the Planning Portal's account. It is not a price, and it is not a promise that your glass room qualifies. Outside England, ask the local authority. The electrics page cited here is written for England and Wales [S3].
Get glass extension quotes
Say whether the room is separated or opened up. 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
Glass itself is on the glaziers page. The structure is a builders job when walls and bases are involved. Circuits belong with electricians. All services.
Questions about glass extensions
How much is a glass extension?
A separated conservatory and a glass room opened into the house are different jobs. Ask for quotes that say which one they are pricing, and that list the base, the frame and the glass.
Is a glass extension planned like any other extension?
For planning, yes. The Planning Portal says adding a conservatory falls within the same rules as any other home extension. If you go past those limits, a householder application is likely. The size tests live on the extensions guidance, not in a separate glass tariff.
When is a conservatory exempt from building regulations?
The Planning Portal says conservatories are normally exempt only when they are at ground level, under 30 square metres, separated from the house by external-quality walls, doors or windows, have an independent heating system with separate controls, meet the glazing and fixed-electrical rules, and are single storey. Miss one of those and you should not assume the exemption.
What if we remove the back doors and open the room up?
That is the opposite of the separation condition. The Planning Portal says any new structural opening between the conservatory and the existing house needs building regulations approval, even where the conservatory itself would have been exempt. Do not knock that opening through yourself. Ask building control and a designer first.
Do the electrics in a glass room matter?
Yes. Even on the exemption list, glazing and any fixed electrical installations must comply with the applicable requirements. The Planning Portal also says electrical installation work in a home must comply with the building regulations, and that a registered competent person can self-certify. Use a registered electrician for new circuits.
What about a deposit on a glass room?
Citizens Advice says some traders charge to quote, so ask before they visit. Avoid a large upfront payment, consider buying materials yourself, and do not agree a deposit above 25% if you cannot avoid one. Glass is often ordered early, which is a reason to keep the receipt.
Does QuoteZila check glazing firms?
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 post a glass extension on QuoteZila?
Yes. Say whether the room will be separated by external-quality doors or opened into the house, and add your Cheshire postcode. Up to five matched local businesses can quote. QuoteZila is free for customers and local businesses.
Related reading
- Electrician cost in Cheshire: for circuits in the new room
- Roof repair cost: if the glass meets an existing roof that already leaks
- Glaziers
- All cost guides
Part of Cost guides. All services
Related trades
Cost guides
Related pages
- Lean-To Conservatory Cost: What to Ask. Planning a lean-to conservatory in Cheshire? See what changes the quote, from wall height and roof pitch to the base, glazing and rules on size and separation.
- New Windows Cost: What Changes the Price. The Federation of Master Builders puts double glazing from £200 a window, and a window fitter at £25 to £35 an hour. Prices vary. QuoteZila does not set prices.
Sources
- QZ1: QuoteZila product fact. QuoteZila pricing line.
- QZ2: QuoteZila product fact. QuoteZila FAQ.
- S1: Planning permission: conservatories, Planning Portal. Accessed 2026-10-27. https://www.planningportal.co.uk/permission/common-projects/conservatories/planning-permission/
- S2: Building regulations: conservatories, Planning Portal. Accessed 2026-10-27. https://www.planningportal.co.uk/permission/common-projects/conservatories/building-regulations/
- S3: Building regulations: electrics, Planning Portal. Accessed 2026-10-27. https://www.planningportal.co.uk/permission/common-projects/electrics/building-regulations-general-information
- 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