What do flat rooflights in Barnes involve?
Thinking about flat rooflights in Barnes? The short answer: fixed double or triple glazed rooflights for flat roofs and extensions. The longer answer depends on your roof, which is why we survey before we price.
Mansard and loft conversions are common across London, and roof windows are often set out alongside dormers on the rear slope. Typical uses for flat rooflights include kitchen extensions, side returns and flat-roofed back rooms.
Jobs in Barnes are planned around access: whether the roof can be reached from the garden, whether a hoist or crane is needed, and where we can park. We check this when we measure.
Options we can specify in Barnes
- Double or triple glazing
- Solar-control or self-cleaning outer pane
- Insulated kerb or timber upstand built to suit
- Integral or fitted blinds
- Rain sensor if paired with an opening unit
- Double or triple glazed with a warm-edge spacer
- Pairs with an opening unit where you also need ventilation
Before you order: points to check
- 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
Planning, building control and Barnes
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.
See our building regulations guide for U-values, glazing limits and self-certification.
Guide prices for Barnes
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
- Send the details. Postcode, rough size and a photo of the roof and room.
- 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.
- Fit and make good. We fit, seal, test and finish the reveal, then hand over the paperwork.
Neighbouring towns
More we do in Barnes
Flat rooflights in Barnes: questions
Double or triple glazing?
Double glazing suits most domestic jobs. Triple glazing improves thermal performance and cuts noise from rain, which is worth it over bedrooms or where the energy calculation is tight.
How long does it take?
Fitting into a prepared upstand usually takes a day. Forming a new opening in an existing roof, including making good inside, is often two to three days.
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.
Can you work alongside my builder in Barnes?
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 Barnes?
Yes — someone needs to let us into the room below and, where possible, show us how the roof is reached.
