Flat rooflights for Isleworth: the essentials
For Isleworth homes and buildings we offer flat rooflights: fixed double or triple glazed rooflights for flat roofs and extensions. We measure first, specify to the opening and confirm any planning or building-control points before quoting.
Mansard and loft conversions are common across London, and roof windows are often set out alongside dormers on the rear slope. Think of flat rooflights for landings, bathrooms and rear extensions with flat roofs.
We work across Greater London, including Isleworth, and in neighbouring towns such as Hounslow and Richmond. Access, parking and how the glass reaches the roof are all checked at the survey.
What you can choose
- Double or triple glazing
- Plastered or lined internal reveal
- Frame colours: anthracite, black, white or RAL
- Solar-control or self-cleaning outer pane
- Integral or fitted blinds
- Slim sightlines from inside — mostly glass, little frame
- Double or triple glazed with a warm-edge spacer
Before you order: points to check
- 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
Do you need permission in Isleworth?
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. In an extension, glazing including rooflights is normally limited to 25% of the new floor area plus any windows or doors the extension covers, unless a whole-house calculation shows otherwise.
Our planning guide covers each nation in more detail.
Guide prices for Isleworth
These are typical supply-and-fit ranges. For an address in Isleworth, scaffold, a hoist for heavy glass, or a new structural opening can move the figure, which is why we survey first.
| 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 |
How the job runs
- Send the details. Postcode, rough size and a photo of the roof and room.
- Measure and check. A surveyor visits Isleworth, measures and checks structure and access.
- 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
Other services in Isleworth
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.
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.
Do I need to be at home for the survey in Isleworth?
Yes — someone needs to let us into the room below and, where possible, show us how the roof is reached.
How do I book a survey in Isleworth?
Send your postcode and, if you can, a photo of the roof and the room. We offer a survey date when we reply.
