Guide prices
Like-for-like swap
Old dome or unit removed and disposed of, new glass rooflight fitted to the existing sound kerb
New upstand and swap
Old kerb taken off, new insulated upstand built, roof covering made good, new unit fitted
Opening or large unit
Electric or larger replacement, including making good inside
Guide ranges for supply & fit; building control notice fee extra in England and Wales. Your price is fixed in a written quote after we have seen photos or surveyed. Scaffold, access towers or a crane are priced separately if the job needs them, and building control fees, where a job needs them, are shown as their own line.
Is your address covered?
Jobs across TW7, TW3 and TW5 are part of our normal cover for Isleworth. We are not an office on the high street. Our fitting teams come out to the property from wherever they are working that week. Neighbouring places such as Hounslow and Heston are covered on the same terms, so a house on the edge of town is no harder to book than one in the centre.
Already bought your unit?
Which works out better, buying your own or letting us supply? It depends on what you value. Buying your own gives you control of the product and what you pay for it. Letting us supply puts the whole job, unit and fitting, under one written quote. On a customer-supplied unit we still measure it against the opening, look at the upstand, and inspect the condition it arrived in. Warranty on the product sits with whoever sold it, while the fitting carries our own guarantee.
On the day, we cover
- Building notice given to the council in England and Wales, with its fee on the quote
- Packers, an adaptor or a new insulated upstand where the old kerb falls short
- New unit bedded, fixed and sealed exactly as its maker shows
- Inside finishes — We check the condition of the plaster and trim around the opening from inside.
- Dome to glass upgrades — We check that the opening and kerb suit a flat glass unit before quoting a dome-to-glass swap.
From arrival to clean-up
Protection comes before tools. Floors, furniture and stairs get covered, and the ceiling below the opening is sheeted to catch dust. Up top, the fitters confirm the opening is square and the upstand or flashing suits what the maker specifies. Fixing follows, then weather-sealing into the membrane, felt or tiles. Only once the roof is tight do they turn to the internal reveal. Time on site for a replacement rooflight: one day, weather permitting.
Regulations for Isleworth properties
England's rules in short: permitted development usually covers a rooflight on a house roof provided it doesn't stick out more than 0.15 m or rise above the ridge, though a listed building always needs consent and some streets have Article 4 directions. Building regulations apply to new openings, and replacements go through building control; as we are not registered with a competent person scheme, we use a building notice and show the fee on the quote. The energy limit for rooflights in existing homes is 2.2 W/m²K, and the 2026 Approved Document L, in force from 24 March 2027, keeps that figure.
What to send for a quick quote
For fit-only work, the product details matter most: the link, the spec sheet, or a photo of the label on the box. Alongside that, send pictures of the roof and the ceiling below, approximate opening sizes, the type of roof covering, and how someone would get onto the roof. For supply and fit, the same photos and sizes do the job. Finish with your postcode, such as TW7.
Common questions in Isleworth
What if my roof opening is the wrong size for the replacement rooflight?
We find out before the fitting day, not on it. If the opening is slightly out, it can usually be adjusted by trimming or by packing out the upstand. If it is a long way off, the choice is between altering the opening and changing the unit. Bear in mind that rooflights are often sold by builder's opening size rather than external size, so check which one your measurement refers to.
Does a rooflight need building regulations approval?
A new opening usually needs building regulations approval. A replacement is a controlled fitting: it must be self-certified by an installer registered with a competent person scheme or notified to building control. We are not registered with a scheme, so replacements we fit are notified to building control with a building notice, and the council's fee is shown on your quote.
Do you cover Isleworth?
Yes. Fitters travel to addresses in Isleworth and the surrounding districts, including TW7. We do not run an office there; the survey and the fitting happen at your property. A few island and remote postcodes are covered by arrangement; if yours is one, we confirm travel and dates before quoting.
Get in touch with the details of your Isleworth property and we will explain what the job involves and what it costs.

