Flat rooflights in Sevenoaks: what is involved?
Our flat rooflights service in Sevenoaks covers fixed double or triple glazed rooflights for flat roofs and extensions. Every job starts with a survey of the opening, the roof covering and the room below, and a fixed written price.
Larger gardens in much of the South East mean deeper rear extensions, and deeper rooms need light from above rather than only from the doors. Flat rooflights suit landings, bathrooms and rear extensions with flat roofs.
Neighbouring towns include Tonbridge (10 km) and Orpington (13 km). We offer a survey date when we reply to your enquiry.
What you can choose
- Rain sensor if paired with an opening unit
- Insulated kerb or timber upstand built to suit
- Plastered or lined internal reveal
- Integral or fitted blinds
- Solar-control or self-cleaning outer pane
- Double or triple glazed with a warm-edge spacer
- Fixed units are simple, quiet and low-maintenance
What to check first
- Rooflights count toward glazing in an extension, which matters for Building Regulations energy and overheating rules
- New openings in an existing roof need a structural check on joists
Do you need permission in Sevenoaks?
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. Listed buildings need listed building consent, flats have no householder permitted development rights, and an Article 4 direction can remove the rights in some conservation areas.
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.
Our planning guide covers each nation in more detail.
What do flat rooflights cost in Sevenoaks?
Guide prices for flat rooflights in Sevenoaks are the same as anywhere we work — what changes the price is the job: access, structure, scaffold and finishing.
| 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 |
The process, step by step
- Tell us what you have. Send the TN13 postcode, a rough size and a couple of photos.
- Survey. We measure the opening, check the roof build-up and agree the options.
- Fixed quote. Product, work and price in writing — nothing is ordered until you agree.
- Fitting and handover. We install, clean down and leave product and warranty documents.
Neighbouring towns
More we do in Sevenoaks
Common questions
Do flat rooflights leak?
A well-fitted flat rooflight should not leak. Leaks almost always come from the upstand or membrane detailing, not the glass unit, which is why the upstand height and the way the roof covering is dressed up and under the frame matter more than the brand.
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.
Is the survey in Sevenoaks free?
Yes for new installations. Repair visits are charged, and we tell you the price before we book.
Will I need planning permission in Sevenoaks?
English householder permitted development (Class C) normally covers rooflights that stand no more than 0.15 m proud of the roof plane and stay below the highest part of the roof.
