Guide prices
Diagnostic visit
Roof and inside inspected, cause found, written repair price
Reseal and re-flash
Failed sealant and flashing taken out, joints cleaned, resealed and taped
Upstand or membrane repair
Rotten kerb section or roof membrane at the upstand repaired
Guide ranges. The first visit is charged and priced before booking; any repair is priced in writing before work starts. 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.
Coverage in and around Windsor
Covering Windsor means covering the people who live and work there, not a single postcode. We take on domestic and commercial jobs in SL4, SL3 and SL1, and are happy to quote further out in Slough and Egham. If your address sits between towns, tell us and we will confirm whether it falls in our normal area or needs travel set out separately on the quote.
On the day, we cover
- Rotten kerb sections replaced where the timber has gone soft
- Inside check of stains, frame drainage channels and the reveal
- Controlled water test where it helps pin down the entry point
- Warranty and who fitted it — We ask who fitted the rooflight and when before working on it.
- Age of the rooflight — We weigh the age and condition of the unit before recommending a repair.
How a repair visit goes
A repair visit starts outside. The fitter looks at the roof around the unit for ponding, split membrane, loose flashing and failed sealant, then moves inside to check stains, the frame and the condensation channels. Where it helps, a controlled water test narrows down the entry point. Before leaving, they explain what they found and whether a small fix can be done within the agreed visit, or needs a separate written quote.
Planning and building rules in England
In England, a new rooflight opening generally needs building regulations approval because the roof structure is altered and the glazing must meet energy rules: 2.2 W/m²K for a rooflight in an existing home, or 1.4 W/m²K (or WER Band B) for a roof window. Planning is often not needed on a house: permitted development covers rooflights that stand no more than 0.15 m proud of the roof slope and sit below the highest part of the roof. Flats, listed buildings and areas with an Article 4 direction are different, so we check your address first.
What to send us
Before booking a visit, send what you can: a photo of the ceiling or reveal where water shows, a photo of the rooflight from outside, the roof covering if you know it, and whether it is one rooflight or several. We use that to price the visit and to bring the right materials.
Common questions in Windsor
Can you replace just the misted glass?
Often, yes. Misting between the panes means the sealed unit has failed, but the frame around it may be perfectly sound. Where the maker's design allows the glass to be changed, we measure the unit and fit a replacement, which costs less than a whole new rooflight. Where it does not, or the frame is also worn out, we explain why replacement is the better option.
Is it condensation or a leak?
Condensation tends to appear on cold mornings, on the inner face of the glass, and runs down the frame. A leak usually follows rain or wind from a particular direction and often stains the ceiling around the opening. Blocked condensation channels can make the two look alike. Photos and a note of when it happens help us narrow it down before the visit.
Why is my rooflight leaking?
The usual causes are sealant that has cracked or pulled away, flashing or membrane that has perished at the edges, condensation channels blocked with dirt, water ponding against the kerb, or a seal failing on the glass unit. Sometimes the water is coming in elsewhere and running along to the rooflight. A diagnostic visit finds the real source before anyone starts applying sealant.
Got a leak or a misted unit in Windsor? Send photos first and we will tell you what the visit costs before booking.

