What do flat rooflights involve?
Our flat rooflights service in Cornwall covers fixed double or triple glazed rooflights for flat roofs and extensions. We survey every job before fixing the price.
Holiday lets and second homes across the South West often want roof windows with blinds and remote opening for when the house is empty. Stone cottages, slate roofs and conservation areas are common in the South West, and conservation-profile rooflights keep the roofline quiet.
Towns in Cornwall
Specification options in Cornwall
- Rain sensor if paired with an opening unit
- Insulated kerb or timber upstand built to suit
- Double or triple glazing
- Integral or fitted blinds
- Frame colours: anthracite, black, white or RAL
- Fixed units are simple, quiet and low-maintenance
- Double or triple glazed with a warm-edge spacer
Planning and building rules in England
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.
For English homes the energy rules ask for rooflights of 2.2 W/m²K or better and roof windows of 1.4 W/m²K (or WER Band B); most modern double glazed units meet both. 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.
What do flat rooflights cost in Cornwall?
Guide prices for flat rooflights in Cornwall 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 |
How the job runs
- Tell us about the roof. Send the postcode, rough sizes and a photo or two through the form, WhatsApp or the guide-price tool.
- Free survey. For new installations a surveyor measures the opening, checks the roof build-up and talks through glass and options.
- Fixed written quote. You get the product, the work and the price in writing. Nothing is ordered or paid for until you agree.
- Fitting and handover. We fit, seal and make good, then hand over product data, warranties and any certificate paperwork.
Flat rooflights in nearby areas
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.
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.
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.
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.
Will I need planning permission in Cornwall?
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.
