- Postcode district
- SM5
- 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
- Sutton, Mitcham, Morden
- Building rules
- England
Is a sliding door for an extension a good fit for your home in Carshalton?
Most homeowners choosing sliding doors for extensions want the same things: more light, a clear view and a door that is easy to live with.
If your Carshalton builder is about to pour the screed, confirm the finished floor level for the threshold first, because it is very hard to change afterwards.
For a garden room at the bottom of a Carshalton garden, think about access: large glass panels need a clear route from the road to the site.
- Agreeing a fitting date with your builder lets the extension be made weathertight on programme, so plastering and flooring can follow without waiting on the doors.
- 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.
- We provide the structural opening size and fitting tolerances in writing, giving your builder a clear target and avoiding disputes about who measured what.
Daylight in Carshalton and what it means for your glass
Daylight in Carshalton runs from about 7 h 51 min in December to 16 h 37 min in June, with the noon sun at roughly 15° and 62° respectively. Use that to choose your glass: standard low-E double glazing for north and east elevations, and consider solar-control or triple glazing for sunny south and west walls.
What should you budget for sliding doors for extensions in Carshalton?
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 |
| 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.
Timescales for sliding doors for extensions in Carshalton
Nothing is ordered until you sign off the surveyed specification. The door is made from the finished opening sizes (typically 6–8 weeks for slimline systems after check survey sign-off), and fitting usually takes 1–2 days, scheduled to the build programme. If you are in Sutton or Mitcham, the same process and prices apply.
Do you need approval in Carshalton?
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.
Finishes and extras for sliding doors for extensions
- Corner opening. Sliding panels meeting at a corner with no post, for extensions open on two sides.
- Triple glazing. For low-energy extensions or north-facing walls, subject to panel size limits.
- Three or four panels. More panels for wider extension openings, with one or more sliding.
Questions about sliding doors for extensions in Carshalton
Do you fit sliding doors for extensions in Carshalton?
Yes. We survey and fit sliding doors for extensions in Carshalton and across Greater London, including nearby Sutton and Mitcham. Start with a guide price online or call us, and we will arrange a free survey for a new or replacement door.
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 do I get a level threshold in an extension?
A level or flush threshold in an extension needs the finished floor level inside to be set relative to the door sill and the outside paving before the screed goes down. Outside, a drainage channel is needed across the threshold so rain cannot run in. Our thresholds guide explains the options.
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.