- Postcode district
- AL1
- 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
- Radlett, Harpenden, Hatfield
- Building rules
- England
Why choose sliding doors for extensions in St Albans?
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.
Self-building in St Albans or elsewhere in Hertfordshire? Ask for the sliding doors to be quoted as part of a wider glazing package so the frames, colours and glass match across the house.
When your St Albans extension is going through Building Control, keep the energy information for the doors to hand, as the inspector may ask for it.
- 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.
- We provide the structural opening size and fitting tolerances in writing, giving your builder a clear target and avoiding disputes about who measured what.
- 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.
Planning glass for the light in St Albans
The midday sun over St Albans ranges from about 15° at the winter solstice to about 62° at midsummer. Low-angle winter light reaches further into a room through a tall door, which is one reason taller panels are worth considering; on south or west walls, pair them with solar-control glass.
Typical costs for sliding doors for extensions around St Albans
The table shows guide prices for common sizes, supplied and fitted, including VAT. Your exact price is fixed in a written quote once the opening in your St Albans home has been measured.
| Overall width | Typical panels | Guide price (fitted, inc VAT) |
|---|---|---|
| 2.1 m | 2 panels | £5,495–£6,795 |
| 2.4 m | 2 panels | £5,995–£7,295 |
| 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.
From survey to fitted door in St Albans
A surveyor visits your St Albans home to check the wall, the structure above and the floor levels, and talks through glass and finish. Any building work is planned to the engineer's design, the door is made to 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.
Rules for sliding doors for extensions in England
Doors in an English extension go through the extension's Building Regulations approval. Under Approved Document L, the total area of windows, roof windows and doors is normally capped at 25% of the extension's floor area plus any openings the extension removes, unless your designer shows compensating improvements; the glass must be safety glazing under Approved Document K.
Which options matter for sliding doors for extensions?
- Solar-control glass. Coated glass for south- and west-facing extensions prone to summer overheating.
- Corner opening. Sliding panels meeting at a corner with no post, for extensions open on two sides.
- Three or four panels. More panels for wider extension openings, with one or more sliding.
Questions about sliding doors for extensions in St Albans
How soon can you survey in St Albans?
Surveys in the AL1 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.
When should I order sliding doors for an extension?
Order sliding doors for an extension as soon as the opening is built and a check survey can be done, and agree the target fitting date with your builder in advance. Slimline doors typically take 6–8 weeks to make after sign-off. Getting a quote from drawings early means the specification is settled and only the final measurements are needed.

