- Postcode district
- SG6
- Survey
- Free for new and replacement doors
- Typical lead time
- Typically 6–8 weeks for slimline systems after check survey sign-off
- Guide price
- From £5,095 inc VAT
- Nearby
- Hitchin, Stevenage, Biggleswade
- Building rules
- England
Are sliding doors for extensions right for your Letchworth Garden City home?
The right door depends on the opening, the room and the way you use the garden. Here is how sliding doors for extensions tend to work out in practice:
Planning an extension in Letchworth Garden City? Send us the drawings before the steel is ordered, so the beam above the doors can be designed with the door in mind.
When your Letchworth Garden City extension is going through Building Control, keep the energy information for the doors to hand, as the inspector may ask for it.
- Setting the finished floor level before the screed goes down allows a low threshold, typically 15–25 mm, or a flush one with a drainage channel outside.
- Being involved at drawing stage means the opening is formed to suit the door, rather than the door being compromised to suit an opening built a few centimetres out.
- Slimline aluminium systems with interlocks typically around 20–25 mm maximise the glass in a new rear wall, keeping the view as open as possible.
Sunlight, glass and orientation in Letchworth Garden City
Because Letchworth Garden City sees long summer days (about 16 h 44 min) and short winter ones (about 7 h 45 min), the elevation your door faces makes a real difference. With the midday sun at about 15° in winter, a south-facing door brings light well into the room; a west-facing door catches hot late-afternoon sun in summer.
Sliding doors for extensions and garden rooms prices in Letchworth Garden City
Guide prices are the same across Hertfordshire. They cover the door supplied and fitted into a prepared opening, including VAT, with options itemised in your quote.
| Overall width | Typical panels | Guide price (fitted, inc VAT) |
|---|---|---|
| 2.1 m | 2 panels | £5,495–£6,795 |
| 3.0 m | 2 panels | £6,895–£8,395 |
| 3.6 m | 2 panels | £7,795–£9,495 |
See every size on the sliding doors for extensions page or try the guide price tool.
Survey, manufacture and fitting around Letchworth Garden City
Here is the usual sequence in Letchworth Garden City: guide price, free survey, written quote, any building work, then manufacture (typically 6–8 weeks for slimline systems after check survey sign-off). Fitting typically takes 1–2 days, scheduled to the build programme. Nearby, we also survey in Hitchin, Stevenage and Biggleswade.
Do you need approval in Letchworth Garden City?
In England, sliding doors in a new extension are covered by the extension's own Building Regulations application rather than a separate door notification. Approved Document L limits the glazed area: windows, roof windows and doors should not normally exceed 25% of the extension's floor area plus the area of any windows or doors lost to the extension, unless the extra glass is compensated for elsewhere. The doors must also meet the energy and safety glazing standards.
Specification choices for sliding doors for extensions in Letchworth Garden City
- Triple glazing. For low-energy extensions or north-facing walls, subject to panel size limits.
- Two-panel slimline. One sliding and one fixed panel, suiting openings up to around 3.6 m depending on the system.
- Solar-control glass. Coated glass for south- and west-facing extensions prone to summer overheating.
Questions about sliding doors for extensions in Letchworth Garden City
Do you fit sliding doors for extensions in Letchworth Garden City?
Yes. We survey and fit sliding doors for extensions in Letchworth Garden City and across Hertfordshire, including nearby Hitchin and Stevenage. Start with a guide price online or call us, and we will arrange a free survey for a new or replacement door.
What structural opening size should my builder leave for sliding doors?
Your builder should leave the structural opening size we give in writing for your chosen door, which is the frame size plus a small fitting tolerance on each side and at the head. The exact figure depends on the system and the threshold detail. We confirm it from your drawings early, then check the built opening before the door is made.
Why does the steel beam matter for sliding doors?
The steel beam above an extension's sliding door matters because every beam bends a little under load, and a large sliding door needs a straight, level head to run freely. If the engineer knows a wide slider will sit under the beam, they can design for low deflection. Too much movement can make panels stiff or bind.
How much do sliding doors for an extension cost?
Slimline sliding doors for an extension have a guide price of £7,795–£9,495 for a 3.6 m opening and £9,595–£11,695 for a 4.8 m opening, fitted, inc VAT at standard 2.1 m height. Taller doors, extra panels, special glass and flush thresholds move the price. Your written quote after the check survey fixes it.

