- Postcode district
- PE21
- 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
- Spalding, Sleaford, Horncastle
- Building rules
- England
What sliding doors for extensions offer homes in Boston
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.
Where an extension in Boston faces south or west, ask about solar-control glass, because a wall of glass in a single-storey room can overheat in summer.
When your Boston extension is going through Building Control, keep the energy information for the doors to hand, as the inspector may ask for it.
- 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.
- We provide the structural opening size and fitting tolerances in writing, giving your builder a clear target and avoiding disputes about who measured what.
How much sun will a door in Boston get?
Daylight in Boston runs from about 7 h 34 min in December to 16 h 56 min in June, with the noon sun at roughly 14° and 60° 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 Boston?
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 Boston home has been measured.
| Overall width | Typical panels | Guide price (fitted, inc VAT) |
|---|---|---|
| 2.4 m | 2 panels | £5,995–£7,295 |
| 4.8 m | 3 panels | £9,595–£11,695 |
| 6.0 m | 4 panels | £11,395–£13,895 |
See every size on the sliding doors for extensions page or try the guide price tool.
From survey to fitted door in Boston
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 Spalding or Sleaford, the same process and prices apply.
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.
Specification choices for sliding doors for extensions in Boston
- Triple glazing. For low-energy extensions or north-facing walls, subject to panel size limits.
- Corner opening. Sliding panels meeting at a corner with no post, for extensions open on two sides.
- Flush threshold. A level floor from inside to out, with a drainage channel set into the patio.
Questions about sliding doors for extensions in Boston
Can you match other doors and windows in my Boston home?
Usually, yes. Most aluminium and uPVC systems come in standard RAL colours and finishes, and we can quote dual colour where the inside and outside need to differ. Bring photos of existing frames to the survey.
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 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.

