When a roof window drips, the glass is rarely to blame. This guide looks at the real causes of leaks around VELUX and similar roof windows on Patchway homes.
A drip below a roof window does not always mean the window has failed. On the lofts and dormers of Patchway's semis and bungalows, the more common causes are the flashing, the sealing, condensation or the roof covering around the frame. We work out which, and fix that.
Flashing that has worn or shifted
Every roof window sits in a flashing kit matched to the roof covering. If the flashing was fitted poorly, has corroded or has been disturbed by later work, water can get under it and run down the lining. It is the most frequent cause of genuine leaks, and it tends to show in heavy, wind-driven rain.
Sealing and the frame
Seals and gaskets age. If the sealing at the frame has hardened, split or shrunk, rainwater can pass through the gap. Sometimes the original installation left a weak spot at a corner that only opens up after years of movement. This is normally repairable without replacing the whole window.
Older installations on bungalow and dormer lofts have often been through many seasons of sun, frost and rain. The materials simply wear. A thorough inspection of the frame edges, corners and sealing strips tells us whether a reseal is enough or a refit is needed.
Condensation that looks like a leak
Moisture on the inside of the glass, or running down the lining, may be condensation. Poor insulation or vapour control around the window, or a lack of airflow in the room, can cause it. It can look just like a leak, so we check the conditions and the lining before pointing at the roof.
The roof around the window
Slipped tiles, damaged slates or failed lead beside the window can feed water towards the frame. Misting between the panes is a separate issue: it means the sealed glass unit has failed and needs replacing. We separate these causes, because the right repair depends entirely on which one applies.
- Stains on the lining or ceiling around the opening.
- Drips only during wind-driven rain.
- Misting between the two panes of glass.
- Damp or algae on the roof beside the window.
What we do about it
We check inside for staining and damp, then examine the window, flashing and covering from safe access. Repairs may mean refixing or replacing the flashing, resealing, renewing the lining or insulation, or fitting a new window. We explain what we found and why before starting.
We would rather find the cause properly than seal over it. A bead of sealant on the outside may stop a drip for a few weeks, but if the flashing is the real fault, the leak will come back and the damage behind it will carry on.
Frequently Asked Questions
Is it the glass leaking?
Rarely. Glass is sealed in the window. Water that appears usually comes from the flashing, the sealing, condensation or the covering. Misting between panes is a failed sealed unit, which is a different problem.
Can the window be fixed without replacing it?
Rarely. Glass is sealed into the window frame. Water that appears usually comes from the flashing, the sealing, condensation or the covering around it. Misting between the panes is a failed sealed unit, which is a separate problem with a separate fix.
Why does it only leak in some weather?
Wind-driven rain pushes water sideways under flashings and through small gaps, which a vertical shower would not reach. A leak that only shows in strong wind points to an edge, flashing or sealing fault, and tells us where to look first.
Talk to our team about VELUX and roof window installation in Patchway
Every roof is different — the fastest way to get an accurate answer is a quick chat with our team.