Sliding doors for extensions and garden rooms across Gwynedd
A few practical points decide whether sliding doors for extensions suit a particular room and opening:
If your Gwynedd 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 Gwynedd garden, think about access: large glass panels need a clear route from the road to the site.
- 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.
- We provide the structural opening size and fitting tolerances in writing, giving your builder a clear target and avoiding disputes about who measured what.
- 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.
Guide prices for sliding doors for extensions in Gwynedd
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 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 |
| 4.8 m | 3 panels | £9,595–£11,695 |
| 6.0 m | 4 panels | £11,395–£13,895 |
Every size is on the sliding doors for extensions page.
Daylight and glass in Gwynedd
In Gwynedd the shortest day has roughly 7 h 33 min of daylight and the longest about 16 h 57 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.
Towns we cover in Gwynedd
We survey and fit sliding doors for extensions in 9 towns across Gwynedd, including the LL23, LL40, LL49, LL53, LL55, LL57 postcode districts.
Approvals 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.
Questions about sliding doors for extensions in Gwynedd
Do I need building approval for sliding doors for extensions in Gwynedd?
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.
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.

