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RooflightInstallers.co.uk
Carshalton · SM5 · Greater London

Rooflight leak repairs in Carshalton

Look at the roof after rain. If water sits in a puddle against one side of the rooflight, that ponding may be the real culprit, soaking into the joint where the kerb meets the membrane. Fixing it can mean adjusting the falls, raising the upstand or redressing the membrane, not just fresh sealant. We carry out rooflight leak repairs across Carshalton by tracing the source first. The visit is charged, at a figure agreed before you book, and any further work is quoted in writing.

Guide price from £145 · Charged visit, then repair priced before any work

Guide prices in Carshalton

Diagnostic visit

£145 – £195including VAT at 20%

Roof and inside inspected, cause found, written repair price

Reseal and re-flash

£295 – £645including VAT at 20%

Failed sealant and flashing taken out, joints cleaned, resealed and taped

Upstand or membrane repair

£645 – £1,445including VAT at 20%

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.

Where our fitters travel

Fitters travel to the job, so the address is what counts. In Carshalton that means postcode districts SM5, SM1 and SM6, and the same teams can just as easily take on work in Wallington, about 1 mile away, or Sutton at roughly 2 miles. Survey and fitting dates are offered according to fitter availability, and travel is built into the quote rather than added later.

Included in the work

  • Membrane splits at the upstand cut back and patched
  • Lifted flashing or tape removed and renewed
  • Rotten kerb sections replaced where the timber has gone soft
  • Leak or condensation — We work out whether the water is coming from outside or forming inside on cold glass.
  • Warranty and who fitted it — We ask who fitted the rooflight and when before working on it.

How a repair visit goes

Most of the effort on a repair visit goes into finding the cause. We start with your account of when it leaks: heavy rain, wind from one direction, or cold mornings, which points towards condensation. That shapes where we look first. Findings are photographed so you can see them for yourself. You then get a clear explanation and, where needed, a written repair quote, fixed before anything further is booked.

Planning and building rules in England

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 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 Carshalton

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.

Will resealing fix my leaking rooflight?

Sometimes. If the sealant has simply aged and the flashing, upstand and glass are sound, a careful reseal on a dry day can solve it. If the real problem is ponding water, a low upstand or a perished membrane, fresh sealant will only hide it for a while. We tell you which one you are dealing with before recommending any work, and quote the proper fix in writing.

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.

Send photos of the problem in Carshalton and we will price the visit before you book it.

Rear extension at dusk with lit rooflights and a roof lantern
Ready when you are

Leak repairs in Carshalton

Send photos of the problem and we will tell you what a visit costs before booking.

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