Sliding doors for extensions and garden rooms across County Londonderry
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 County Londonderry or elsewhere in County Londonderry? 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.
If your County Londonderry builder is about to pour the screed, confirm the finished floor level for the threshold first, because it is very hard to change afterwards.
- We provide the structural opening size and fitting tolerances in writing, giving your builder a clear target and avoiding disputes about who measured what.
- 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.
- Garden rooms benefit from the same approach, with a door sized to the frame and a header designed to carry the roof without pressing down on the door.
Guide prices for sliding doors for extensions in County Londonderry
These are guide prices for fitted doors, including VAT. They run from an entry-level system to a premium one at the same size; the survey confirms which suits your opening.
| Overall width | Typical panels | Guide price (fitted, inc VAT) |
|---|---|---|
| 1.8 m | 2 panels | £5,095–£6,195 |
| 3.0 m | 2 panels | £6,895–£8,395 |
| 4.0 m | 3 panels | £8,395–£10,195 |
| 4.8 m | 3 panels | £9,595–£11,695 |
Every size is on the sliding doors for extensions page.
Daylight and glass in County Londonderry
At the latitude of County Londonderry, the midday sun climbs to about 58° in late June but only about 12° in late December, when daylight lasts around 7 h 10 min against 17 h 22 min in midsummer. A south-facing sliding door for an extension lets that low winter sun deep into the room; on a west or south elevation, solar-control glass keeps summer afternoons comfortable.
Towns we cover in County Londonderry
We survey and fit sliding doors for extensions in 7 towns across County Londonderry, including the BT45, BT46, BT47, BT49, BT52, BT55 postcode districts.
Approvals in Northern Ireland
Extensions in Northern Ireland are approved by district council building control under the Building Regulations (Northern Ireland), including their doors. We take on work in Northern Ireland by arrangement.
Questions about sliding doors for extensions in County Londonderry
Do I need building approval for sliding doors for extensions in County Londonderry?
In Northern Ireland the Building Regulations (Northern Ireland) apply through district council building control; work there is by arrangement. We confirm the right route for your property at survey, so the paperwork is in place before fitting.
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.
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.
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.

