- Postcode district
- BT47
- Survey
- Free, area covered by arrangement
- Typical lead time
- Typically 6–8 weeks for slimline systems after check survey sign-off
- Guide price
- From £5,095 inc VAT
- Nearby
- Strabane, Limavady, Dungiven
- Building rules
- Northern Ireland
Sliding doors for extensions and garden rooms in Derry/Londonderry: what to know
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:
Planning an extension in Derry/Londonderry? Send us the drawings before the steel is ordered, so the beam above the doors can be designed with the door in mind.
When your Derry/Londonderry extension is going through Building Control, keep the energy information for the doors to hand, as the inspector may ask for it.
- 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.
- Telling the engineer the door type and span early lets them design the beam above it to limit deflection, protecting the smooth running of large sliding panels.
Planning glass for the light in Derry/Londonderry
In Derry/Londonderry the shortest day has roughly 7 h 10 min of daylight and the longest about 17 h 22 min. The noon sun sits near 12° above the horizon in winter and 58° 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.
How much do sliding doors for extensions cost in Derry/Londonderry?
Guide prices are the same across County Londonderry. 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 |
| 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.
What happens when you order sliding doors for extensions in Derry/Londonderry?
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 Strabane or Limavady, the same process and prices apply. Derry/Londonderry is in an area we cover by arrangement: the survey is still free, and survey dates, delivery and any travel cost for delivery and fitting are confirmed in your quote before you order.
Rules for sliding doors for extensions in Northern Ireland
In Northern Ireland, an extension needs building control approval from your district council, which covers the doors and glazing. Work in Northern Ireland is by arrangement.
Specification choices for sliding doors for extensions in Derry/Londonderry
- Three or four panels. More panels for wider extension openings, with one or more sliding.
- Triple glazing. For low-energy extensions or north-facing walls, subject to panel size limits.
- Solar-control glass. Coated glass for south- and west-facing extensions prone to summer overheating.
Questions about sliding doors for extensions in Derry/Londonderry
Do you fit sliding doors for extensions in Derry/Londonderry?
Yes, by arrangement. Derry/Londonderry is in an area we cover by arrangement: the survey is still free, and survey dates, delivery and any travel cost for delivery and fitting are confirmed in your quote before you order.
Why does the steel beam matter for sliding doors?
The steel beam above an extension's sliding door matters because every beam bends a little under load, and a large sliding door needs a straight, level head to run freely. If the engineer knows a wide slider will sit under the beam, they can design for low deflection. Too much movement can make panels stiff or bind.
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.
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.