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What a patio door replacement quote should list
A patio door replacement price is the price of a sliding frame in the opening you already have, or of a wider hole if you ask for one. Compare quotes that say whether the opening stays the same width.
Last reviewed:The door that slides
A patio door, for this quote, means a sliding door: panels that pass each other, a track, rollers, and an interlock where the panels meet. It is not a hinged French pair and it is not a run of folding leaves. If the quote uses those words, stop and ask which product is being priced. The replacement is the frame in your opening, the glass, the ironmongery, and the making-good where the old frame came out. A photograph of a show home is not a specification.
The table is the lines to make the fitter write. VAT registration, when taxable turnover for the last 12 months goes over £90,000, is a tax rule and not a door price [S5].
| Line | What to make the fitter write |
|---|---|
| Number of sliding panels and which one moves | A three-panel set is not a two-panel set |
| Track, rollers and interlock, named | Wear happens in these parts |
| Cill drainage and the level of the outside paving | Water sitting in the track is a specification |
| Opening width and height, marked as unchanged or as wider | Wider work is a support question [S3] |
| Glass specification, not the word standard | The U-value limit is in Approved Document L [S2] |
| Making good inside and the outside cill | Plaster and render are easy to omit |
| Taking the old frame away | A missing waste line is not included by silence |
| VAT | Included or not. Registration when taxable turnover for the last 12 months goes over £90,000 [S5] |
Rollers, the interlock and the cill
Ask the fitter to stand at the door and name what is tired. Rollers that have dropped make the panel drag. An interlock that does not meet lets weather in at the meeting stile of a slider, which is a different detail from a hinged pair. The cill has to shed water. If the patio slabs have been raised over the years, they can sit higher than the track and hold water against the door. That is a paving question as well as a frame question. Say so on the job if you want the slabs altered, and do not assume the glazier will lift them.
Roller adjustment is the fitter's method. If the panel is only stiff, you can still ask for a replacement quote and compare it with a repair quote. They are different jobs. A repair that leaves the old frame is not the replacement the booklet is talking about when it lists door units.
Same hole, or a wider one
Write the measurement you want. "About the size of the current door" is not a width. Measure the brick opening in two places, because old openings lean, and put both numbers in the job as approximate. If both fitters are pricing the opening you have, their frames should be close. If one of them has priced a wider structural opening, the totals cannot be compared.
Lancaster's replacement-window leaflet, issued 21 January 2013, says the competent-person route does not remove a building regulations application where the opening is widened and a new support lintel goes in [S3]. Keep that as a prompt to ask your own building control body. It is not a rule made for Cheshire, and the leaflet's old thermal numbers are not used here. Propping and cutting belong in the builder's method for building control.
The certificate, and the controlled fitting
The GOV.UK booklet applies to England and was updated on 3 November 2014 [S1]. Replacement of window and door units is an example of work to tell a building control body about unless a competent person scheme installer certifies it [S1]. FENSA is named for replacement doors [S1]. Expect a certificate within 30 days of completion, and contact the scheme if it does not come [S1]. Most repairs are outside that list, with stated exceptions that include glazing units [S1]. A full new door unit is the example, not a dab of sealant.
The Planning Portal building regulations page says replacement glazing has been covered since 1 April 2002 and that an external door is a controlled fitting [S2]. Heat loss, safety, air supply, means of escape and ventilation are in scope [S2]. The U-value must not be exceeded. See Approved Document L for the maximum [S2]. Ask the fitter to write the maximum they are meeting. The portal also describes safety glazing zones and escape-window sizes. Those millimetre lines are not copied here, so a patio quote is not a clone of a hinged-door page. Ask the fitter to confirm glass in the door against the approved document, in writing.
GOV.UK: building regulations approval. QuoteZila is not affiliated with this organisation.
Planning permission stays with the look of the door
The Planning Portal planning page says repairs and new doors of a similar appearance to the original usually do not need planning permission [S6]. A slider that replaces a slider of a similar look is the ordinary case to describe. A new bay is treated as an extension on that page, which is a different project [S6]. Listed buildings, conservation areas, Article 4 directions and leases can still restrict you [S6]. Upper-floor side windows have a 1.7 metre rule that a ground-floor patio door does not automatically share [S6]. If the rear wall faces a neighbour and the new door is much larger in appearance, ask the local planning authority rather than guessing [S6].
How to compare two replacement quotes
Citizens Advice wants a quote, meaning a fixed price, rather than an estimate, meaning a rough guess [S4]. Do not rely on a spoken figure [S4]. Try for written quotes from at least three traders [S4]. Be wary if the price is far below the others or if the trader will not write the specification down [S4]. The paper should show a fixed total, a breakdown, how long the figure stays open, and whether VAT is included [S4].
If a deposit is unavoidable, do not agree to more than 25%, take a receipt, and ask whether the money is protected if the firm stops [S4]. Some traders charge for coming to quote. Ask first. Ask to see insurance that runs until the frame is in [S4]. An insurance-backed guarantee is sometimes offered with replacement doors. Read the exclusions before you pay for the extra [S4].
Put both quotes against the table. The one that omits the cill, the waste or the certificate route is not the cheaper version of the same job.
Cheshire openings, measured on the ground
QuoteZila is new, starting in Cheshire with Crewe, Nantwich and Sandbach. Anyone in the UK can still post a job or register a business [QZ5]. A rear slider in Crewe may face a yard that is already higher than the cill. Measure the opening and the step, and say whether the paving will be altered. Replies depend on who has joined [QZ5].
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.
Up to five matched local businesses can send quotes [QZ2]. QuoteZila is free for customers and local businesses [QZ1].
Posting a job is not open yet
Glaziers, joiners and builders are the trade pages. Roof repair cost, locksmith cost and fencing cost are other guides to a written price.
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.
Locks, keys and the night you can close it
A replacement is unfinished if you cannot lock it. Ask the quote to name the lock, whether the key is a replacement for the one you already hold, and who keeps the spare on the day the old frame leaves. That is joinery and ironmongery, not a structural method, and it is a line two sliders can disagree on while looking like the same door. If the panel must be left unglazed overnight, say you want that risk written down rather than discovered at dusk.
Count the sliding panels and say which one moves. Ask the quote to name the track, the rollers and the cill, and to say whether the opening stays the width it is now. A price that says only patio door can hide a different glass specification and a different making-good line. Photograph the step and the outside paving from the ground, and say whether that paving will change. If one fitter widens the hole and another keeps it, they are not pricing the same job.
Jobs you might post
These are examples, not taken from real job posts.
- "Crewe. Two-panel sliding patio door. Opening must stay the same size. Please name rollers, interlock and cill drainage, and say whether the slabs outside are higher than the track."
- "Nantwich kitchen. I want a replacement slider only. If you think the opening should be wider, price that as a separate line and do not start it."
- "Sandbach. The panel drags. Please quote a repair and a full unit replacement as two totals, with waste included on the replacement."
Questions about patio door quotes
Is a like-for-like slider still building regulations work?
Yes, as a class of job. The GOV.UK booklet lists replacement of door units as an example to tell a building control body about, unless a competent person scheme installer certifies it. The Planning Portal says an external door is a controlled fitting and that replacement glazing has been covered since 1 April 2002. Keeping the same hole in the wall does not take the door out of that description. It does change whether anyone is also talking about a new support.
What should the quote say about the cill and the rollers?
Ask for the track, the rollers and the cill as named parts, plus whether the outside paving sits above the track and will hold water. A patio door fails in use when the rollers or the drainage in the cill are wrong, even if the glass looks right. Ask the quote to price the track, the rollers and the cill as named lines. If the quote says only "patio door", ask which of those parts are included.
When does widening change the paperwork?
Lancaster City Council's 2013 note says a competent-person installer does not remove a building regulations application where the opening is made wider and a new support lintel is installed. That note is from Lancashire, not a Cheshire rule. If you want the same opening, write "opening unchanged" on the job so a fitter cannot assume a wider hole. If you do want it wider, ask for that as its own line.
How long does the booklet say you should wait for a certificate?
You should receive a certificate within 30 days of completion, and you should contact the scheme if it does not arrive. FENSA is one of the schemes the booklet names for replacement doors. The lists in the booklet are examples, not a complete catalogue. A missing certificate is a question for the scheme, not a reason to guess a completion date.
What about deposits and VAT?
Citizens Advice says that if you cannot avoid a deposit, do not agree to more than 25%, and get a receipt. Some traders charge for a quote. Ask before they visit. A business must register for VAT when taxable turnover for the last 12 months goes over £90,000. Ask whether VAT is inside the total.
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.
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Related pages
- Resealing Windows: What to Compare. What changes a window reseal quote: a draught at the frame, mist between the panes, or a new glass unit. This guide prints no price.
- Triple Glazed Windows: What Changes the Price. What changes the price of triple glazed windows: frame material, size and style, glass spec, fitting, making good, building regulations, FENSA and VAT.
Sources
- QZ1: QuoteZila product fact. QuoteZila public pricing line.
- QZ2: QuoteZila product fact. QuoteZila terms, customers.
- QZ5: QuoteZila product fact. QuoteZila coverage wording.
- S1: Building work, replacements and repairs to your home, GOV.UK. Accessed 2026-10-25. https://www.gov.uk/government/publications/building-work-replacements-and-repairs-to-your-home/building-work-replacements-and-repairs-to-your-home
- S2: Building regulations: doors and windows, Planning Portal. Accessed 2026-10-25. https://www.planningportal.co.uk/permission/common-projects/doors-and-windows/building-regulations
- S3: Building Control Guidance Note 05, Lancaster City Council. Accessed 2026-10-25. https://www.lancaster.gov.uk/assets/attach/1344/Leaflet-5-Replacement-Windows-to-Dwellings.pdf
- S4: Before you get work done on your home, Citizens Advice. Accessed 2026-10-25. https://www.citizensadvice.org.uk/consumer/getting-home-improvements-done/before-you-get-building-work-done/
- S5: Register for VAT, GOV.UK. Accessed 2026-10-25. https://www.gov.uk/register-for-vat
- S6: Planning permission: doors and windows, Planning Portal. Accessed 2026-10-25. https://www.planningportal.co.uk/permission/common-projects/doors-and-windows/planning-permission