What do flat rooflights in Sidcup involve?
Flat rooflights in Sidcup means fixed double or triple glazed rooflights for flat roofs and extensions. We cover the DA14 district and the rest of Greater London, with a survey before any price is fixed.
London homes often run deep from front to back, so the middle of the ground floor is the darkest space — exactly where an overhead rooflight earns its keep. In Sidcup, as anywhere, flat rooflights are the usual choice for landings, bathrooms and rear extensions with flat roofs.
Neighbouring towns include Bexley (4 km) and Welling (4 km). We offer a survey date when we reply to your enquiry.
Choices for your Sidcup project
- Integral or fitted blinds
- Insulated kerb or timber upstand built to suit
- Square, rectangular or long-format sizes
- Solar-control or self-cleaning outer pane
- Frame colours: anthracite, black, white or RAL
- Pairs with an opening unit where you also need ventilation
- Slim sightlines from inside — mostly glass, little frame
What to check first
- Needs a properly formed upstand — usually at least 150 mm above the finished roof surface (check the manufacturer's figure)
- Rooflights count toward glazing in an extension, which matters for Building Regulations energy and overheating rules
Consents for flat rooflights in Sidcup
In England a rooflight on a house is usually permitted development under Class C if it projects no more than 150 mm beyond the roof slope and sits no higher than the ridge. A rooflight on a side-facing slope must be obscure-glazed, and fixed shut unless the opening part is more than 1.7 m above the floor.
Under Approved Document L, a rooflight added to an English home must achieve at least 2.2 W/m²K (horizontal plane), and a roof window 1.4 W/m²K or Window Energy Rating Band B. The Future Homes and Buildings Standards, published in March 2026, apply from 24 March 2027 and keep the 2.2 W/m²K limit for rooflights.
Read the planning permission guide before you commit to a design.
Guide prices for Sidcup
The ranges below are typical for straightforward jobs; your fixed price follows a survey of your roof.
| Option | Guide price inc VAT | Ex VAT |
|---|---|---|
| Large or triple glazed (1500 × 2500 mm and up) | £2,395 – £4,195 | £1,995 – £3,495 |
| Mid-size double glazed (1000 × 2000 mm) Typical | £1,675 – £2,395 | £1,395 – £1,995 |
| Small double glazed (up to 1000 × 1000 mm) | £1,195 – £1,795 | £995 – £1,495 |
What happens next
- Tell us what you have. Send the DA14 postcode, a rough size and a couple of photos.
- Survey. We measure the opening, check the roof build-up and agree the options.
- Agree the quote. You approve the specification and price before anything is ordered.
- Fitting and handover. We install, clean down and leave product and warranty documents.
Nearby towns
Related work in Sidcup
Common questions
Can you fit into my existing flat roof?
Yes. We form a new opening, trim the joists, build and waterproof an upstand and make good the ceiling. A survey confirms the joist direction and roof build-up first.
Will it make the room too hot?
A big unglazed-to-sky area can add solar gain in summer. Solar-control glass, a blind, or pairing a fixed unit with an opening one keeps it comfortable.
Can a flat rooflight be walked on?
Not unless it is designed as a walk-on unit with structural laminated glass. A standard flat rooflight is for light only — if the roof is used as a terrace, choose a walk-on rooflight instead.
Can you work alongside my builder in Sidcup?
Yes. On new extensions we fit once the opening and upstand are ready and coordinate dates with your builder.
Do I need to be at home for the survey in Sidcup?
Yes — someone needs to let us into the room below and, where possible, show us how the roof is reached.
