Flat rooflights for Carshalton: the essentials
Thinking about flat rooflights in Carshalton? 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. Flat rooflights suit landings, bathrooms and rear extensions with flat roofs.
From Carshalton to Wallington, Sutton and Mitcham, the same survey-first process applies: measure, specify, fix the price, then fit.
Options we can specify in Carshalton
- Frame colours: anthracite, black, white or RAL
- Double or triple glazing
- Insulated kerb or timber upstand built to suit
- Square, rectangular or long-format sizes
- Solar-control or self-cleaning outer pane
- Fixed units are simple, quiet and low-maintenance
- Even, top-down daylight across the whole room
Before you order: points to check
- New openings in an existing roof need a structural check on joists
- The roof membrane must be dressed up the upstand before the unit goes on
Planning, building control and Carshalton
Most rooflights on English houses do not need planning permission, provided they keep within 150 mm of the roof surface and below the ridge line. 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.
Building Regulations Approved Document L sets a limiting U-value of 2.2 W/m²K for new or replacement rooflights in existing homes, measured in the horizontal plane; roof windows need 1.4 W/m²K or a Band B energy rating. Replacing a rooflight or roof window can be self-certified by an installer registered with an authorised competent person scheme; otherwise building control approval is needed.
Our planning guide covers each nation in more detail.
Guide prices for Carshalton
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 |
From enquiry to finished job
- Tell us what you have. Send the SM5 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.
Flat rooflights near Carshalton
Related work in Carshalton
Common questions
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.
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.
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.
Do I need to be at home for the survey in Carshalton?
Yes — someone needs to let us into the room below and, where possible, show us how the roof is reached.
Is the survey in Carshalton free?
Yes for new installations. Repair visits are charged, and we tell you the price before we book.
