Are sliding doors for extensions right for homes in Cornwall?
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.
Where an extension in Cornwall faces south or west, ask about solar-control glass, because a wall of glass in a single-storey room can overheat in summer.
When your Cornwall 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.
- 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.
- We provide the structural opening size and fitting tolerances in writing, giving your builder a clear target and avoiding disputes about who measured what.
Guide prices for sliding doors for extensions in Cornwall
Guide prices are the same across Cornwall. 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) |
|---|---|---|
| 3.6 m | 2 panels | £7,795–£9,495 |
| 4.0 m | 3 panels | £8,395–£10,195 |
| 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 Cornwall
Daylight in Cornwall runs from about 8 h 01 min in December to 16 h 26 min in June, with the noon sun at roughly 16° and 63° respectively. Use that to choose your glass: standard low-E double glazing for north and east elevations, and consider solar-control or triple glazing for sunny south and west walls.
Towns we cover in Cornwall
We survey and fit sliding doors for extensions in 15 towns across Cornwall, including the EX23, PL12, PL14, PL15, PL25, PL27 postcode districts.
Approvals in England
Doors in an English extension go through the extension's Building Regulations approval. Under Approved Document L, the total area of windows, roof windows and doors is normally capped at 25% of the extension's floor area plus any openings the extension removes, unless your designer shows compensating improvements; the glass must be safety glazing under Approved Document K.
Questions about sliding doors for extensions in Cornwall
Can you match other doors and windows in my Cornwall home?
Usually, yes. Most aluminium and uPVC systems come in standard RAL colours and finishes, and we can quote dual colour where the inside and outside need to differ. Bring photos of existing frames to the survey.
Can you work with my builder and architect?
Yes, working with your builder, architect and structural engineer is the normal way we approach extension doors. We can provide technical details, opening sizes, threshold requirements and fixing information, and attend site for the check survey. Your builder forms the opening and prepares the floor, and our installers fit the doors to the agreed programme.
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.

