- Postcode district
- L37
- 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
- Maghull, Southport, Bootle
- Building rules
- England
Is a sliding door for an extension a good fit for your home in Formby?
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:
Where an extension in Formby faces south or west, ask about solar-control glass, because a wall of glass in a single-storey room can overheat in summer.
Self-building in Formby or elsewhere in Merseyside? 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.
- 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.
- 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.
- 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.
Daylight in Formby and what it means for your glass
Daylight in Formby runs from about 7 h 27 min in December to 17 h 03 min in June, with the noon sun at roughly 13° 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.
Guide prices for sliding doors for extensions in Formby
Guide prices are the same across Merseyside. 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 |
| 2.4 m | 2 panels | £5,995–£7,295 |
| 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 Formby?
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 Maghull or Southport, 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.
Choosing the specification
- Flush threshold. A level floor from inside to out, with a drainage channel set into the patio.
- 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.
Questions about sliding doors for extensions in Formby
Do you fit sliding doors for extensions in Formby?
Yes. We survey and fit sliding doors for extensions in Formby and across Merseyside, including nearby Maghull and Southport. Start with a guide price online or call us, and we will arrange a free survey for a new or replacement door.
Can you work with my builder and architect?
Yes, working with your builder, architect and structural engineer is the normal way we approach extension doors. We can provide technical details, opening sizes, threshold requirements and fixing information, and attend site for the check survey. Your builder forms the opening and prepares the floor, and our installers fit the doors to the agreed programme.
Can you measure from drawings rather than the built opening?
We can quote from drawings, but we manufacture from a check survey of the built opening, because real openings often differ slightly from the plans. Making a large made-to-measure door from drawings alone risks it not fitting. If a programme makes that unavoidable, any arrangement and who carries the risk would be agreed in writing first.
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.