- Postcode district
- SE3
- 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
- Lewisham, Greenwich, Catford
- Building rules
- England
Are sliding doors for extensions right for your Blackheath home?
Most homeowners choosing sliding doors for extensions want the same things: more light, a clear view and a door that is easy to live with.
If your Blackheath builder is about to pour the screed, confirm the finished floor level for the threshold first, because it is very hard to change afterwards.
Planning an extension in Blackheath? Send us the drawings before the steel is ordered, so the beam above the doors can be designed with the door in mind.
- 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.
- 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.
Planning glass for the light in Blackheath
The midday sun over Blackheath ranges from about 15° at the winter solstice to about 62° at midsummer. Low-angle winter light reaches further into a room through a tall door, which is one reason taller panels are worth considering; on south or west walls, pair them with solar-control glass.
Guide prices for sliding doors for extensions in Blackheath
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) |
|---|---|---|
| 2.4 m | 2 panels | £5,995–£7,295 |
| 3.0 m | 2 panels | £6,895–£8,395 |
| 3.6 m | 2 panels | £7,795–£9,495 |
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 Blackheath?
A surveyor visits your Blackheath home to check the wall, the structure above and the floor levels, and talks through glass and finish. Any building work is planned to the engineer's design, the door is made to 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.
Do you need approval in Blackheath?
In England, sliding doors in a new extension are covered by the extension's own Building Regulations application rather than a separate door notification. Approved Document L limits the glazed area: windows, roof windows and doors should not normally exceed 25% of the extension's floor area plus the area of any windows or doors lost to the extension, unless the extra glass is compensated for elsewhere. The doors must also meet the energy and safety glazing standards.
Options to consider for your sliding door for an extension
- Triple glazing. For low-energy extensions or north-facing walls, subject to panel size limits.
- Corner opening. Sliding panels meeting at a corner with no post, for extensions open on two sides.
- Flush threshold. A level floor from inside to out, with a drainage channel set into the patio.
Questions about sliding doors for extensions in Blackheath
Do I need building approval for sliding doors for extensions in Blackheath?
In England a replacement door is a controlled fitting, so compliance is arranged through a competent person scheme installer or Building Control; new openings need a Building Regulations application. 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.
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.