- Postcode district
- LL29
- 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
- Conwy, Llandudno, Abergele
- Building rules
- Wales
What sliding doors for extensions offer homes in Colwyn Bay
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 Colwyn Bay builder is about to pour the screed, confirm the finished floor level for the threshold first, because it is very hard to change afterwards.
For a garden room at the bottom of a Colwyn Bay garden, think about access: large glass panels need a clear route from the road to the site.
- 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.
- 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.
Light and sun in Colwyn Bay
In Colwyn Bay the shortest day has roughly 7 h 30 min of daylight and the longest about 17 h 00 min. The noon sun sits near 13° above the horizon in winter and 60° 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.
Typical costs for sliding doors for extensions around Colwyn Bay
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 Colwyn Bay home has been measured.
| Overall width | Typical panels | Guide price (fitted, inc VAT) |
|---|---|---|
| 2.4 m | 2 panels | £5,995–£7,295 |
| 3.6 m | 2 panels | £7,795–£9,495 |
| 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 Colwyn Bay?
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 Conwy or Llandudno, the same process and prices apply.
Rules for sliding doors for extensions in Wales
In Wales, sliding doors in an extension are approved as part of the extension's Building Regulations application, and the glazing must meet the Welsh energy and safety glazing requirements, including the limits on how much of an extension can be glazed.
Specification choices for sliding doors for extensions in Colwyn Bay
- Solar-control glass. Coated glass for south- and west-facing extensions prone to summer overheating.
- Triple glazing. For low-energy extensions or north-facing walls, subject to panel size limits.
- Three or four panels. More panels for wider extension openings, with one or more sliding.
Questions about sliding doors for extensions in Colwyn Bay
Do I need building approval for sliding doors for extensions in Colwyn Bay?
In Wales a replacement door must meet the Building Regulations as applied in Wales, arranged through a registered installer or Building Control. We confirm the right route for your property at survey, so the paperwork is in place before fitting.
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.
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.
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.

