VELUX Window Installers › Aberdare › Guide
Roof windows get blamed first when water appears nearby, but the glass is seldom at fault. A roof window is a system of frame, flashing, sealing and insulation, set into a roof covering that has to shed heavy rain. Aberdare's wet, windy weather finds the weak point in any of them.
Flashing that does not suit the roof
The flashing is the metal and sealing that joins the window frame to the slates or tiles. If it is the wrong kit for the covering, or was fitted badly, water gets under the edge and runs down inside. This is the most common cause we see.
Older roofs that were re-covered after the window went in are especially prone, because the new tiles may not sit properly with the old flashing. A tidy-looking repair from a previous owner can hide a flashing that was never right for the tiles in the first place, and it fails the next wet winter.
Failed sealing and worn parts
Seals and sealing strips age. Sun, frost and heavy rain perish them, and the gap that opens lets water in at the corners first. Moss and debris collecting on the upper side of the frame can also hold water against the joint.
From the ground you will not see this clearly. Check the ceiling and lining around the window for stains, and tell us where they are. Also note whether the stains are on one side only, since a streak running down from the top corner points to a different fault from one at the bottom.
- Stains at the corners of the lining.
- Water marks below the sill of the window.
- Soft or flaking plaster around the reveal.
- Drips only during heavy or wind-driven rain.
Condensation that looks like a leak
Not every wet window is leaking. Warm, damp air from a bedroom or bathroom condenses on cold glass and frames, then runs down and drips. In a loft room with poor insulation or no vapour control, this can happen all winter.
The pattern gives it away: wet mostly on cold mornings, in dry weather as well as wet. Better ventilation and correct lining fix that, not new flashing. If the loft room is used as a bedroom, drying clothes or showering nearby adds to it, so keep the room ventilated while we look into the cause.
Problems with the roof around the window
Sometimes the window is fine and the covering beside it is not. A slipped slate, cracked tile or blocked valley above the frame sends water towards the window and makes it look like the culprit. We follow the path of the water upslope.
On Aberdare terraces, moss and shared stacks nearby can add to the problem. We look at the surrounding roof as well as the window itself. Cleared moss, refixed slates and sound gutters nearby can stop the window being blamed for something it did not do, and we tell you which is which.
What we do about it
We check inside and out, find where the water enters, and tell you whether it needs new flashing, resealing, a replacement sealed unit or a repair to the roof covering. We do not replace a window that does not need it.
If the glass has misted between the panes, that is a failed sealed unit, which is a separate matter from a leak. We explain what we find in plain terms, so you can decide what to do about it with the facts in front of you and without any pressure.
Need velux window installers in Aberdare? See our velux window installers in Aberdare page, or call 07766 547309.
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Common Questions
Can I seal a leaking roof window myself?
We advise against it. Getting to the roof is dangerous, and a bead of sealant on a badly flashed window usually hides the problem for a short time. Mark the stain, put a bowl down, and call us for a proper look.
Why does my window only leak in heavy rain?
That points to a flashing or covering fault, where water only gets in when it is driven hard. Wind pushes rain sideways up the valley slopes and finds gaps that stay dry in light showers. We trace it from inside and out.
How can I tell condensation from a leak?
Condensation appears on cold mornings, often in dry weather, and wets the glass and frame first. A leak shows after rain, with staining at the corners or below the sill. If you are unsure, tell us what you see and when.
Get a Quote in Aberdare
Tell us what the roof is doing in Aberdare and we will look at it. Call 07766 547309, message us on WhatsApp or use the form below.