- Postcode district
- SE23
- Survey
- Free for new and replacement doors
- Typical lead time
- Typically 4–6 weeks for the door after the opening is measured; building work scheduled around approvals
- Guide price
- From £6,595 inc VAT
- Nearby
- Sydenham, Catford, Dulwich
- Building rules
- England
New and widened openings for sliding doors in Forest Hill: what to know
Most homeowners choosing sliding doors for new openings want the same things: more light, a clear view and a door that is easy to live with.
Thinking about a wider opening in Forest Hill but unsure of the size? Mark it out on the wall inside and out with tape, then picture the furniture and the view before you decide.
For homes in Forest Hill that are listed or covered by an Article 4 direction, ask the council about the new opening before paying for structural calculations.
- Telling the engineer that a sliding door will sit beneath the beam lets them limit its deflection, which matters because a beam that sags can stop panels sliding freely.
- Widening a standard patio opening to a larger span can transform how a room connects to the garden, giving a wall of glass rather than a doorway.
- If the work affects a party wall, notice can be served under the Party Wall etc. Act 1996 (England and Wales) before it starts, avoiding disputes with neighbours later.
Sunlight, glass and orientation in Forest Hill
Daylight in Forest Hill runs from about 7 h 50 min in December to 16 h 38 min in June, with the noon sun at roughly 15° and 62° 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.
How much do sliding doors for new openings cost in Forest Hill?
These figures combine an aluminium sliding door with the building work to form or widen the opening, including structural calculations and VAT. Your price is fixed in a written quote once the wall in your Forest Hill home has been surveyed; council fees are extra.
| Overall width | Typical panels | Guide price (fitted, inc VAT) |
|---|---|---|
| 1.5 m | 2 panels | £6,595–£7,295 |
| 4.0 m | 3 panels | £10,295–£11,595 |
| 6.0 m | 4 panels | £13,295–£15,095 |
See every size on the sliding doors for new openings page or try the guide price tool.
Timescales for sliding doors for new openings in Forest Hill
A surveyor visits your Forest Hill 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 4–6 weeks for the door after the opening is measured; building work scheduled around approvals — and fitting usually takes 3–5 days of building work, then 1–2 days to fit the door.
Rules for sliding doors for new openings in England
A new or wider opening in England needs Building Control approval for the structural work as well as compliance for the door itself under Approved Documents L and K. Expect structural calculations, a steel beam and, where a party wall is involved, notices under the Party Wall etc. Act 1996.
Which options matter for sliding doors for new openings?
- Window to door conversion. Cutting down below an existing window to form a door opening to the garden.
- Concealed steel. Setting the beam so it sits above the ceiling line, giving a cleaner head detail inside.
- Temporary door or boarding. A secure, weathertight closure while the made-to-measure door is being manufactured.
Questions about sliding doors for new openings in Forest Hill
Is the price different in Forest Hill?
No. Guide prices for sliding doors for new openings are the same across mainland Britain, including Forest Hill. The fitted price depends on size, system, glass and finish, and any structural work, all fixed in your written quote after survey.
Can you turn a window into a sliding door?
Yes, a window opening can usually be extended down to the floor and often widened to take a sliding door. The work involves removing the masonry below the window, forming a new threshold, and fitting a steel beam or lintel if the opening is widened. Drains, air bricks and floor levels outside need checking, and the work needs a Building Regulations application.
How much does it cost to widen an opening for sliding doors?
Our guide price for forming or widening an opening is £3,595 for 2.4 m and £4,495 for 4.8 m, covering steel, padstones, making good and structural calculations. The door is priced separately, and Building Control fees are set by your council. All figures are guide prices inc VAT, fixed in a written quote after we survey the wall and see what is above it.
Do I need planning permission for a new opening?
Planning rules for altering an elevation depend on the property and where you are, so it is worth checking with your council before you commit. Flats, listed buildings and properties covered by an Article 4 direction are the most likely to need consent. Wales and Scotland have their own planning rules. Our planning guide sets out the questions to ask.