Velux Window Leaking

A roof window interrupts the roof covering, so the details around the opening have to carry rain past the frame and back onto the roof. The flashing kit must suit the covering. Tiles cut short, an unsuitable kit or underlay that has not been lapped back correctly can leave a route for water even when the glazing and frame are sound.

The damp mark inside may be some distance from where water enters. Note whether it appears during rain, which side of the opening becomes wet first and whether water is on the glass or the surrounding trim. Those observations help explain the symptom, but close inspection of the roof is still needed before a repair is specified.

If your Velux window is leaking in the corner, the fault might lie in the flashing at that edge, in the weathering above it or in the window seal. Replacing the visible internal trim would hide the evidence without stopping the water. The relevant question is where water crosses the outside weathering, not simply which corner of the plaster has stained.

Heavy rain can make a defective junction more noticeable, but it does not identify the failed part. We check the surrounding covering as well as the window: a slipped tile above the opening can direct water towards it. The repair should address that route, with the roof covering reinstated correctly rather than relying on a surface smear around the frame.

Moisture on the glass or widespread damp nearby can need a different investigation from a localised rain leak. The site’s ventilation guidance explains that condensation tends to wet wider areas of underlay and timber, whereas a leak can leave a more localised trail. Record when the moisture appears and mention any damp elsewhere in the loft.

A ventilation problem will not be solved by changing a sound flashing, just as adding vents will not repair a broken window seal. If the symptoms extend beyond the opening, the assessment can consider the loft airflow as well. Keep the window complaint specific: water through the frame, water around it and condensation on the room side are not the same description.

Our roof-window service already covers failed seals, worn hinges and leaks around the flashing. Where those parts can be put right and the frame is serviceable, repair may avoid replacing the complete unit. A stiff handle or a sash that no longer sits properly should also be mentioned, because it helps separate an operating fault from the surrounding roof work.

Flashing work must use the appropriate kit for the tile or slate covering and leave the underlay dressed back around the frame. If nearby slates are lifted for access, they need reinstating with the proper laps. A repair is not complete just because the window opens again; the outside weathering has to work as part of the roof.

A rotten frame or failed glazing can make like-for-like replacement into the existing opening more practical. That is different from creating a new opening in the roof. The survey checks the window dimensions, the roof pitch and the covering before the replacement and its flashing are selected. It should also identify what internal making-good is involved.

We supply and fit roof windows across the North East and give an itemised written quote. The window, flashing kit, reinstatement of the covering and internal trim are considered together so you can understand the proposed job. Use the form below to describe when the leak happens; please leave climbing onto the roof and dismantling weathering to someone with suitable access equipment.