From £1,350 per window*
Based on a 1200 x 1200mm window in white, fitted, inc VAT, based on 4 windows fitted.
uPVC Mock Sash Windows
The character of a traditional sliding sash, on our proven uPVC casement mechanism. A budget-friendly way to keep period style without the depth a real sliding sash needs.
Designed, supplied and fitted by our own team across Surrey, Berkshire, North Hampshire, Middlesex and West Sussex. Showroom in Guildford.
Mock sash windows look like a traditional vertical sliding sash, but open like a casement: a fixed pane and a single tilting sash rather than two panels that slide. That makes them a genuine option where a property does not have the depth for a real sliding sash installation.
From £1,350 per window, supplied and fitted, including VAT.*
A+ rated
The only A+ window in our range, with a 1.2 whole window U-value
PAS 24 available
Enhanced security, specified on any window
Quote in 4 working days
Home visit in 2, written quote 2 after that
8 to 10 weeks
Order to installation, then 1 to 2 days on site
10 year guarantee
Insurance backed as standard, plus your FENSA certificate
What uPVC mock sash windows cost
From £1,350 per window, supplied and fitted, including VAT.*
Most window companies will not put a number on a page. We will, because you need one before you invite anyone into your house.
Prices are indicative. Access, the condition of the existing frames and the fitting itself all move the final figure. Your quotation is the accurate number, and it is free.
Spread the cost
Your payment can be spread monthly over a term of up to 10 years.** Finance is provided by Dopple and you apply through our finance portal. A small deposit is due on order, the balance on completion.
How long it takes
| Stage | How long |
|---|---|
| Enquiry to home visit | As little as 2 working days |
| Home visit to quotation | 2 working days, up to 5 for specialist items |
| Order to technical survey | Up to 10 working days |
| Order to installation | Generally 8 to 10 weeks |
| Time on site | Typically 1 to 2 days for a full house |
| Do you need to move out? | No. You stay in the house throughout |
Why quotes are valid for 14 days
Glass manufacturing is heavily energy dependent, so our costs move with energy prices. Rather than pad every quotation against a rise that may not happen, we quote the real number on the day. If it lapses, come back whenever you are ready and we will requote free of charge.
Why homeowners choose uPVC mock sash
You want period character without the price of a real sliding sash. Mock sash gives you the traditional look at a more accessible cost.
You want it where a genuine sliding sash will not fit. Real sliding sashes need depth in the frame that not every property has. Mock sash does not.
You want proven performance, not an unfamiliar mechanism. It shares the same low maintenance, energy efficiency and security as our standard uPVC casement.
You want a wide choice of finishes. 34 colours, including 8 woodgrains, so it can match a period elevation properly.
uPVC mock sash window security
A traditional look does not mean a compromise on security. Every mock sash window can be specified to PAS 24, the enhanced standard Building Regulations require on new homes, which means it has been physically attacked under test conditions and held.
- Can be specified to PAS 24, the enhanced security standard used by Building Regulations
- Trojan multi point shootbolt locking, tested to BS7950
- Reinforced frames and internal beading
- Hinge protection against jemmying
- Lockable handles
Tell your surveyor if security is a priority and we will specify accordingly.
Expertise You Can Trust
Proudly serving Surrey since 1972, we’re a family-run glazing company offering quality windows, doors, conservatories, and bespoke glass solutions. Whether you’re upgrading your home’s look with double glazing, choosing a new front door, or planning a unique orangery, our team is here to bring your vision to life.
Mock sash or traditional sliding sash?
Both give you the classic sash look. The difference is how they open, and what your property can take.
| Mock sash | Traditional sliding sash | |
|---|---|---|
| How it opens | Fixed pane, one tilting sash, like a casement | Two panels that slide vertically |
| Frame depth needed | Standard casement depth | Deeper frame required for the sliding mechanism |
| Maintenance | Low, no sliding mechanism to maintain | Sash cords, weights or spiral balances need occasional attention |
| Look | Close match to a traditional sash from the outside | The genuine period mechanism |
| Price | More accessible | Higher |
Mock sash is the practical choice where the depth is not there for a real sliding sash, or where budget matters more than having the authentic mechanism. Bring a photo of your elevation to the Guildford showroom and we will tell you honestly which suits your house.
Planning your next project? Check if we cover your area.
Sheerwater Glass proudly provides window and door installations, repairs, and glazing services throughout Surrey and the surrounding areas from our showrooms in Guildford and Woking.
To find out whether we cover your area, simply click the button below and check your postcode.
Styles and configurations
A fixed pane with a single top or side hung tilting sash, styled to echo a traditional two over two or six over six sliding sash. Georgian bars and astragal bars are available to complete the period look. Trickle vents fitted where Building Regulations require them.
Colour Options
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White
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Tan
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Cream
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Brown
-
Agate Grey
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Windsor
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Grey
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Slate Grey
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Slate Grey Finesse
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Buckingham Grey
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Pebble Grey
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Basalt Grey Smooth
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Anthracite Grey Smooth
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Hazy Grey Finesse
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Anthracite Grey
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Steel Blue
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Swamp Oak
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Silver D Smooth
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Sage Smooth
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Rosewood
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Pyrite
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Honey Oak Super Matt
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Irish Oak
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Flemish Gold Smooth
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Dark Red
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Dark Green
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Cream White
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Black Ulti Matt
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Black Brown
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Claystone
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Chartwell Green
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AnTEAK
uPVC mock sash specification
| Window Energy Rating | A |
|---|---|
| U-value | 1.2 W/(m²K) whole window, as standard |
| Configuration | Fixed pane with a single tilting sash |
| Frame depth | 70mm, six chamber |
| Maximum sash size | Ask your surveyor |
| Security | Can be specified to PAS 24. Trojan shootbolt locking, tested to BS7950 |
| Colours and finishes | 34, including 8 woodgrains |
| Guarantee | 10 years on frames, glass units and workmanship. 5 years on moving parts and hardware |
Hear from our customers
“Nick from Sheerwater Glass just finished fitting my windows – Great service, quick, efficient and very friendly. Definitely recommend.”
Deborah Proudfoot
Sheerwater Glass Customer
Your Glass Options
| Option | What it does | Standard or upgrade |
|---|---|---|
| Argon fill | Better insulation than air | Standard |
| Low emissivity coating | Reflects heat back into the room | Standard |
| Warm edge spacer bar | Cuts heat loss and condensation at the edge of the glass | Standard |
| Toughened safety glass | Required by Building Regulations in some positions. We will tell you where | Where required |
| Acoustic glass | Worth it on a main road, but only ever as good as the fabric of the building around it. Ask your adviser | Upgrade |
| Laminated security glass | Holds together if broken | Upgrade |
| Obscure and patterned | Bathrooms and overlooked windows | Upgrade |
| Leaded and Georgian bar | Period elevations and conservation areas | Upgrade |
| Upgraded thermal unit | Improves the U-value of the whole window | Upgrade |
| Triple glazing | Best performance, heaviest units. Available on selected frames | Upgrade |
Your guarantee
| Frames, glass units and workmanship | 10 years |
|---|---|
| Moving parts and hardware | 5 years |
| Insurance backed guarantee | QANW, as standard |
| FENSA certificate | Issued automatically on qualifying installations |
The insurance backed part matters: your cover survives even if we are not here to honour it, and we provide it even on installations that do not qualify for FENSA. Most local companies do not.
Questions we get asked
How much do Slimline uPVC windows cost?
From £1,350 per window, supplied and fitted, including VAT, on the basis set out above. Prices are indicative and your quotation is the accurate figure.
Can you match my existing windows and doors?
Usually. Slimline is designed alongside the rest of our range, so a new front door will match. If you are replacing in phases we record your finish so the second phase matches the first. Bring a photo to the showroom and we will tell you honestly whether we can match what you have.
Do I need planning permission?
Usually not, but you might if your house is listed or sits in a conservation area. We will flag it at survey if we think you are affected.
Will I get a FENSA certificate?
Yes, automatically, on every installation that qualifies. You will need it when you sell the house, and we hold a copy in your customer portal.
What happens if something goes wrong in a few years?
Call us. Your workmanship, frames and glass are covered for 10 years and moving parts for 5, backed by a QANW insurance backed guarantee. The Glass and Repairs Surgery at the Guildford showroom is open Tuesday and Thursday afternoons and Saturday mornings.
Can I buy the windows without installation?
Yes. We supply only if you are arranging your own fitting.
Ready to get a quote?
You’ll speak to a real person, not a call centre. We’ll talk you through options, no pressure.
Pricing, finance and page notes
* Prices are indicative starting prices, reviewed regularly. They are based on a 1200 x 1200mm window in white with one side hung opener, a fanlight and a fixed pane below, supplied and fitted including VAT, and an order of four windows to the same property. Colours and woodgrain finishes cost more.
** Finance is provided by Dopple, not by Sheerwater Glass. Sheerwater Glass Ltd is an Introducer Appointed Representative of Social Money Ltd, trading as Dopple, which is authorised and regulated by the Financial Conduct Authority, firm reference number 675283. We introduce you to Dopple and we do not lend or give credit advice. Applications are made through our finance portal and all lending is subject to status and affordability. Dopple provides the rate, the term options and a representative example before you apply.
Specifications vary by window style, so a figure given here for a Slimline casement may not apply to another style, size or material. What governs your installation is the specification in your written quotation and signed contract. If a particular figure matters to your decision, ask your surveyor and we will put it in writing.
