- Postcode district
- CR5
- 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
- Purley, Carshalton, Sutton
- Building rules
- England
Sliding doors for extensions and garden rooms in Coulsdon: what to know
Before you settle on a door type, it helps to know what sliding doors for extensions do well and what to check before you order.
When your Coulsdon extension is going through Building Control, keep the energy information for the doors to hand, as the inspector may ask for it.
Planning an extension in Coulsdon? Send us the drawings before the steel is ordered, so the beam above the doors can be designed with the door in mind.
- A check survey once the opening is built means the door is made to the real dimensions, accounting for any small variation in the brickwork or blockwork.
- 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.
Light and sun in Coulsdon
In Coulsdon the shortest day has roughly 7 h 51 min of daylight and the longest about 16 h 36 min. The noon sun sits near 15° above the horizon in winter and 62° in summer — so glass that faces south collects useful warmth from October to March, while a west-facing door may need solar control to stop it overheating in July.
Sliding doors for extensions and garden rooms prices in Coulsdon
Guide prices are the same across Greater London. 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) |
|---|---|---|
| 2.4 m | 2 panels | £5,995–£7,295 |
| 4.0 m | 3 panels | £8,395–£10,195 |
| 4.8 m | 3 panels | £9,595–£11,695 |
See every size on the sliding doors for extensions page or try the guide price tool.
What happens when you order sliding doors for extensions in Coulsdon?
Here is the usual sequence in Coulsdon: 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 Purley, Carshalton and Sutton.
Rules for sliding doors for extensions in England
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.
Options to consider for your sliding door for an extension
- 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.
- Three or four panels. More panels for wider extension openings, with one or more sliding.
Questions about sliding doors for extensions in Coulsdon
How soon can you survey in Coulsdon?
Surveys in the CR5 district are booked at a time that suits you, and we offer survey dates when we reply to your enquiry. After you approve the written quote, manufacture is typically 6–8 weeks for slimline systems after check survey sign-off.
What sliding doors suit a garden room?
A garden room usually suits a two-panel or three-panel sliding door sized to the front of the building, with a header strong enough to carry the roof without pressing on the frame. Aluminium systems are a common choice because they are stable and need little maintenance. Glass with good insulation helps if the room will be used all year.
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.
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.

