Hello,
A few days ago I noticed what appears to be a leak in the bottom left of my velux window - see pic. It appears to be a damp patch, it’s slightly noticeable that it’s damp to the touch but it’s not wet wet. It seems to be mainly surface as it dried very quickly. We did have a lot of rain and wind the night before, but since then we’ve had some rain and it doesn’t seem to have come back. I have a vague recollection of seeing something smaller months ago, maybe last winter, and dismissing it as poor / discoloured paint (long story). My point being I’m not 100 % convinced this happened “overnight” during the rain as opposed to being a slow / progressive issue.
Some background (sorry this is long but I thought it might be helpful):
The velux is only 2 years old (a replacement) and is the polycarbonate coated type. It’s in an en-suite bathroom associated with a converted loft bedroom. There is a toilet, sink and (never used) shower in the bathroom. In the bedroom there are another 3 velux windows (normal not polycarbonate coated).
In winter all 4 velux windows gather a fair bit of condensation on the inside of the glass, but usually dry by the end of the day if I don’t remember to wipe them down first. The polycarbonate window also seems to gather a fair bit of condensation on the inside of the main frame (not the sash frame - this never has any), you can get wet finger tips if you run your finger along the bottom section on both sides of the frame (yet the damp patch is only on the left). Also when you open the window you can see a fair amount of condensation water above where the seals shut - but it doesn’t seem to be coming in. I’ve never noticed any of that actually dripping down the frame to the painted wall below (where the damp patch appears to be). Well, you can see the occasional drip on the frame of the actual sash part, but it’s very rare and doesn’t seem to make it off the sash part before it dries.
The normal velux windows in the bedroom never show this level of condensation on the frame, perhaps due to a slightly higher temp in the bedroom part or maybe the polycarbonate coating has a tendency to build up more condensation. I also notice that they have a much larger “valley” between the glass and frame at the bottom of the window for the water to well in when it runs down.
I’ve done some googling and it seems this sort of problem could be a proper leak, or condensation. I’ve had a look at the flashing outside the windows and can see no problems - no gaps/holes or debris/moss build up. The tiles around the window (concrete overlapping type) all seem sound and secure - and the foam the installer put under them is still in place.
Except there is one potential problem tile. When looking out the window and up the roof, it is 2 up from the velux (ie one overlapping the tiles that would have had to be removed during installation). It’s on the same side as the damp patch but within the line of the window.
The only problem I can see is that the end 1-2 inches of the under “lip” (where adjacent tiles overlap) is missing from one of the tiles. The top part of the tile on the left is perfectly fine and aligned, but where the tile on the right would have the lip part that goes under the left tile is missing a short segment at the bottom.
As far as I can see the missing part is not long enough to mean that there is any missing “lip” far enough up so that the missing segment reaches the overlapping tile below it. And even in the rain I can see a clear dry few mm around the edge of the missing segment - so it seems there’s no way for water to ingress and it’s an unimportant chip. Perhaps the wind could blow it up to the “hole” on the left, but the wind was in exactly the opposite direction that night. This missing segment could have been there for 25 years since when the original Velux were installed for all I know, or since the recent replacement and they never noticed / fixed it. I’m inclined to think this is coincidence rather than water getting in and tracking all the way down to the window - it seems more likely any problem would be at the top of the window as the water would have to be tracking all the way around the window before leaking in at the bottom. But I mention it just in case it’s not a red herring. A pic is attached.
I was previously leaving the vent on the velux open as I thought that would be better for condensation but Velux’s website says not to do that in very cold weather. Although I can’t see how condensation would get from the vent to the damp patch.
I’ve been inside the roof and looked up at the underside of the window - I can’t see the frame proper but I can see a rafter that runs parallel to the bottom of the frame and that’s bone dry.
Oh and one last thing, we have blinds fitted and I can’t see any evidence of water dripping over the bottom of the blind mount.
I think that’s all the important background. No wait, one more thing, there is a radiator in the other side of the wall to the left from that corner of the window.
So my question is, could this realistically be condensation? It’s not obvious how it could be condensation, especially as I think it appeared very quickly overnight. There only seems to be the occasional condensation drip - but it’s hard to be sure as the polycarbonate coating seems to repel water so you don’t ever really see a “trail” from any drips. Plus I’d have thought such a problem would be more localised to the corner whereas this is a large area damp patch. But it does seem to follow the line of the frame so maybe water runs down the frame and then spreads out where the frame meets the plaster.
The fact it appeared over night in heavy rain makes me think leak - but then we’ve had lots of rain before (albeit I never thought to check it one direction so maybe not *this* wind) and not noticed anything like this. But then we’ve had leaks on the old velux and they always seem to be at the bottom of the sidewall plaster part, not between the frame and top of the sidewall plaster part - so I’m back to condensation.
I’ve invested in a dehumidifier anyway and the first time I turned it on up there (2 days after the patch was first noticed) it said 82 %! Below 60 % elsewhere in the house. I’ve got it down to about 60 - 65 up there over the last couple of days, but still plenty of condensation on the window... yet no damp patch. I’m a bit stumped and the velux approved specialist who installed them is not replying to messages / calls.
Thanks in advance.
A few days ago I noticed what appears to be a leak in the bottom left of my velux window - see pic. It appears to be a damp patch, it’s slightly noticeable that it’s damp to the touch but it’s not wet wet. It seems to be mainly surface as it dried very quickly. We did have a lot of rain and wind the night before, but since then we’ve had some rain and it doesn’t seem to have come back. I have a vague recollection of seeing something smaller months ago, maybe last winter, and dismissing it as poor / discoloured paint (long story). My point being I’m not 100 % convinced this happened “overnight” during the rain as opposed to being a slow / progressive issue.
Some background (sorry this is long but I thought it might be helpful):
The velux is only 2 years old (a replacement) and is the polycarbonate coated type. It’s in an en-suite bathroom associated with a converted loft bedroom. There is a toilet, sink and (never used) shower in the bathroom. In the bedroom there are another 3 velux windows (normal not polycarbonate coated).
In winter all 4 velux windows gather a fair bit of condensation on the inside of the glass, but usually dry by the end of the day if I don’t remember to wipe them down first. The polycarbonate window also seems to gather a fair bit of condensation on the inside of the main frame (not the sash frame - this never has any), you can get wet finger tips if you run your finger along the bottom section on both sides of the frame (yet the damp patch is only on the left). Also when you open the window you can see a fair amount of condensation water above where the seals shut - but it doesn’t seem to be coming in. I’ve never noticed any of that actually dripping down the frame to the painted wall below (where the damp patch appears to be). Well, you can see the occasional drip on the frame of the actual sash part, but it’s very rare and doesn’t seem to make it off the sash part before it dries.
The normal velux windows in the bedroom never show this level of condensation on the frame, perhaps due to a slightly higher temp in the bedroom part or maybe the polycarbonate coating has a tendency to build up more condensation. I also notice that they have a much larger “valley” between the glass and frame at the bottom of the window for the water to well in when it runs down.
I’ve done some googling and it seems this sort of problem could be a proper leak, or condensation. I’ve had a look at the flashing outside the windows and can see no problems - no gaps/holes or debris/moss build up. The tiles around the window (concrete overlapping type) all seem sound and secure - and the foam the installer put under them is still in place.
Except there is one potential problem tile. When looking out the window and up the roof, it is 2 up from the velux (ie one overlapping the tiles that would have had to be removed during installation). It’s on the same side as the damp patch but within the line of the window.
The only problem I can see is that the end 1-2 inches of the under “lip” (where adjacent tiles overlap) is missing from one of the tiles. The top part of the tile on the left is perfectly fine and aligned, but where the tile on the right would have the lip part that goes under the left tile is missing a short segment at the bottom.
As far as I can see the missing part is not long enough to mean that there is any missing “lip” far enough up so that the missing segment reaches the overlapping tile below it. And even in the rain I can see a clear dry few mm around the edge of the missing segment - so it seems there’s no way for water to ingress and it’s an unimportant chip. Perhaps the wind could blow it up to the “hole” on the left, but the wind was in exactly the opposite direction that night. This missing segment could have been there for 25 years since when the original Velux were installed for all I know, or since the recent replacement and they never noticed / fixed it. I’m inclined to think this is coincidence rather than water getting in and tracking all the way down to the window - it seems more likely any problem would be at the top of the window as the water would have to be tracking all the way around the window before leaking in at the bottom. But I mention it just in case it’s not a red herring. A pic is attached.
I was previously leaving the vent on the velux open as I thought that would be better for condensation but Velux’s website says not to do that in very cold weather. Although I can’t see how condensation would get from the vent to the damp patch.
I’ve been inside the roof and looked up at the underside of the window - I can’t see the frame proper but I can see a rafter that runs parallel to the bottom of the frame and that’s bone dry.
Oh and one last thing, we have blinds fitted and I can’t see any evidence of water dripping over the bottom of the blind mount.
I think that’s all the important background. No wait, one more thing, there is a radiator in the other side of the wall to the left from that corner of the window.
So my question is, could this realistically be condensation? It’s not obvious how it could be condensation, especially as I think it appeared very quickly overnight. There only seems to be the occasional condensation drip - but it’s hard to be sure as the polycarbonate coating seems to repel water so you don’t ever really see a “trail” from any drips. Plus I’d have thought such a problem would be more localised to the corner whereas this is a large area damp patch. But it does seem to follow the line of the frame so maybe water runs down the frame and then spreads out where the frame meets the plaster.
The fact it appeared over night in heavy rain makes me think leak - but then we’ve had lots of rain before (albeit I never thought to check it one direction so maybe not *this* wind) and not noticed anything like this. But then we’ve had leaks on the old velux and they always seem to be at the bottom of the sidewall plaster part, not between the frame and top of the sidewall plaster part - so I’m back to condensation.
I’ve invested in a dehumidifier anyway and the first time I turned it on up there (2 days after the patch was first noticed) it said 82 %! Below 60 % elsewhere in the house. I’ve got it down to about 60 - 65 up there over the last couple of days, but still plenty of condensation on the window... yet no damp patch. I’m a bit stumped and the velux approved specialist who installed them is not replying to messages / calls.
Thanks in advance.
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