- Postcode district
- NW7
- 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
- Edgware, Finchley, Hendon
- Building rules
- England
New and widened openings for sliding doors in Mill Hill: what to know
The right door depends on the opening, the room and the way you use the garden. Here is how sliding doors for new openings tend to work out in practice:
Thinking about a wider opening in Mill 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.
If your Mill Hill home is semi-detached or terraced and the new steel would sit on the shared wall, budget time for party wall notices before work starts.
- A structural engineer sizes the steel beam and padstones for the actual loads above, so the opening is designed rather than guessed.
- The door is measured from the finished opening rather than from drawings, so it fits the opening as built, not as it was intended to be built.
- 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.
Light and sun in Mill Hill
Daylight in Mill Hill runs from about 7 h 48 min in December to 16 h 40 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.
What should you budget for sliding doors for new openings in Mill Hill?
Use these guide prices to budget for the whole job in Mill Hill: the door, the steelwork, making good and the engineer's calculations, including VAT. Building Control or warrant fees are charged by the council on top.
| 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 Mill Hill
Here is the usual sequence in Mill Hill: guide price, free survey, written quote, any building work, then manufacture (typically 4–6 weeks for the door after the opening is measured; building work scheduled around approvals). Fitting typically takes 3–5 days of building work, then 1–2 days to fit the door. Nearby, we also survey in Edgware, Finchley and Hendon.
Do you need approval in Mill Hill?
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.
Choosing the specification
- Widening an existing door. Removing masonry each side of an old patio door to take a wider slider.
- Low threshold detail. Adjusting floor and outside levels during the building work to allow a lower sill.
- 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 Mill Hill
Is the price different in Mill Hill?
No. Guide prices for sliding doors for new openings are the same across mainland Britain, including Mill Hill. The fitted price depends on size, system, glass and finish, and any structural work, all fixed in your written quote after survey.
Does the Party Wall Act apply to my new opening?
The Party Wall etc. Act 1996 (England and Wales) may apply if the new steel beam bears on, or is cut into, a wall you share with a neighbour, as is common in semi-detached and terraced houses. If it applies, you must serve notice on the neighbour before the work starts. A rear wall entirely on your own property is less likely to be affected.
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 long does it take to form a new opening?
Forming or widening an opening typically involves 3–5 days of building work, including propping, cutting out, installing the steel and padstones, and making good. The sliding door is then made to the finished opening, which typically takes 4–6 weeks for aluminium, so a secure temporary closure is fitted in between. The door itself typically goes in within one to two days.