- Postcode district
- BT18
- 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
- Newtownabbey, Belfast, Carrickfergus
- Building rules
- Northern Ireland
What sliding doors for extensions offer homes in Holywood
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:
If your Holywood builder is about to pour the screed, confirm the finished floor level for the threshold first, because it is very hard to change afterwards.
Where an extension in Holywood faces south or west, ask about solar-control glass, because a wall of glass in a single-storey room can overheat in summer.
- Being involved at drawing stage means the opening is formed to suit the door, rather than the door being compromised to suit an opening built a few centimetres out.
- 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.
- 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.
How much sun will a door in Holywood get?
In Holywood the shortest day has roughly 7 h 14 min of daylight and the longest about 17 h 17 min. The noon sun sits near 12° above the horizon in winter and 59° 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.
What should you budget for sliding doors for extensions in Holywood?
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) |
|---|---|---|
| 2.1 m | 2 panels | £5,495–£6,795 |
| 3.6 m | 2 panels | £7,795–£9,495 |
| 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.
How fitting works in Holywood
Here is the usual sequence in Holywood: guide price, free survey, written quote, any building work, then manufacture (typically 6–8 weeks for slimline systems after check survey sign-off). Fitting typically takes 1–2 days, scheduled to the build programme. Nearby, we also survey in Newtownabbey, Belfast and Carrickfergus. Holywood 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.
Options to consider for your sliding door for an extension
- Three or four panels. More panels for wider extension openings, with one or more sliding.
- Flush threshold. A level floor from inside to out, with a drainage channel set into the patio.
- Two-panel slimline. One sliding and one fixed panel, suiting openings up to around 3.6 m depending on the system.
Questions about sliding doors for extensions in Holywood
Do I need building approval for sliding doors for extensions in Holywood?
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.
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.
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.
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.

