Leak under velux

[PickledWilly]

We bought a house with an extension in March, with obvious damp patches on the ceiling under the veluxes. Had a roofer in and he checked the flashing and the membrane, and then did a 'cement fillet' around the window to stop leaks. There have been no leaks since we had this done in March and have had some pretty driving rain. Had everything decorated in March once fixed and all good.

In the seriously heavy rain this evening a damp patch has appeared under the velux - am devastated! This is much higher up than the previous damp patches. Anyone know what could be wrong now?

Bumping :-)

Without being on the roof and having a look at it, there’s no way of telling where water might be getting in , sorry not much help .

Could be the fact the wind was very strong in a certain direction with driving rain. Nothing can be done really, all flashing have their limits

I bought a house with a similar problem in 2014. It turned out that the Velux windows had not been installed properly. There is supposed to be some kind of material in the surrounding frame that the Velux window sits in to form a barrier and stop water getting in. For some reason the builders had removed the material from the frame during the installation.

I had to get new installation kits for the windows as (allegedly) the filling material wasn't sold separately.

We had a “leaking” velux. Various people had tried to seal it to no avail. Eventually we had it replaced as it was a very old style and didn’t open properly. The builder found it had been installed incorrectly causing condensation to pool between the window and something (maybe a roof joist?) and then drip. We’ve had no issues at all since in was replaced 6 months ago.

Could be so many things; installation, flashings, loose tiles or ridge tiles on the apex. You'll need a roofer again I think.

Ours leaked because the roof angle was too shallow for the windows, and heavy rain couldn't run off the roof properly (and water was blown back under the tiles when it was windy). We had to replace the windows and retile the roof, so I hope this isn't your problem!

Thanks all - I really hope we don't need to replace windows and re tile!!! Roofer reluctant to come back saying that no roofing work can be guaranteed..

We had this with an old extension. When you say "Velux" is it really a Velux or another make...a copy? We had real Velux in our new extension and the roofer told us that proper Venus windows have three forms of defence against leaks and they rarely happen, but the copies it is far more common.

Difficult but rip it out as otherwise the damage will be largely unseen but significant.

They normally only leak if they have been installed incorrectly, I’ve put 2 on our house ( 15 degree pitch ) and you have to be really careful when fitting not to damage the flashing or cut the foam strips too short.

Could be a leak above the window ( tiles ) and running down .

They are real branded velux

Are you sure it's coming from the outside in?

Just asking as there appears to be a couple of water droplets on the UPVC frame.

I have a couple of velux in my loft conversion, and the amount of condensation I get on the glass is huge, particularly in winter.

I have noticed that if I don't go up there and dry off the glass, fairly regularly, it will puddle at the bottom of the window and once the window ridge is full, will overflow and run down the corners then either drip on the floor or, soak into the plasterwork.

I keep them cracked open a touch and dry regularly to stop this.

If it is under 10 years old it will still have the Velux warranty. Even if the owners didn't register it, Velux can check the manufacturing date. They are really helpful

If over, then yes you need a decent roofer as from what I was told they are excellent and very rarely leak

Hello,

Could you elaborate a little please? The reason I ask is that we have relatively recently replaced Velux windows in a loft conversion and also get quite a lot of condensation on them.

In the main bedroom area are wooden windows that seem to have a bigger ridge and a (bit) less condensation on them. In a small en suite area there’s a polycarbonate window that (seems to have) a smaller ridge and pick up a bit more condensation on the window (it’s a little colder in the en suite), but also on the frame (not only the frame around the glass but the main frame the sash part sits in).

Anyway, that’s kind of background that might be important. My main question is, where exactly does the water soak into the plaster, how big an area does it cover (and is the area “evenly spread”), and how quickly can it “appear”?

The reason I ask is that we noticed quite a large area wet patch overnight recently in the en suite velux. Unlike OP where the damp patch is well below the window, ours starts at the bottom of the main frame. It goes about 1 inch up the side from the bottom left corner, about 6 or 7 inches along the bottom edge and the in the very corner about 3/4 of the way down. In other areas it doesn’t go down more than an inch or two, but it’s quite variable - in the middle it’s maybe only 1 inch, past that it goes about 2 inches down before tapering off to the edge of the patch.

A couple of slight additions. As I said it was damp to the touch - but only barely, not wet wet, and it dried very quickly the following day (by lunchtime) so it seems to be a surface issue. There was a lot of rain and wind overnight, but we’ve never noticed this before no matter the weather. We think it appeared overnight but I can’t guarantee we just didn’t notice. There was a lot of condensation on the window, and I could see a drip a little way down in the corner - but otherwise the frame of the sash was completely dry. The main frame was slightly moist with condensation, but I couldn’t see any obvious drips. When I look outside, as far as I can tell, the flashing all looks fine.

In other words, it’s either a leak coming from a strange place and tracking over - but it seemed to be all “surface” moisture so I can’t see where from and would expect it to be more persistent. But then it came so suddenly, and over such a large area compared to how I interpret what you describe that I can’t see how it could be condensation.

So yeah, would you mind describing your problem in a little more detail please. to see whether ours could be the same, or whether it’s completely different.

@Wingedharpy

Are you sure it's coming from the outside in?

Just asking as there appears to be a couple of water droplets on the UPVC frame.

I have a couple of velux in my loft conversion, and the amount of condensation I get on the glass is huge, particularly in winter.

I have noticed that if I don't go up there and dry off the glass, fairly regularly, it will puddle at the bottom of the window and once the window ridge is full, will overflow and run down the corners then either drip on the floor or, soak into the plasterwork.

I keep them cracked open a touch and dry regularly to stop this.

I should say, my above comment was a reply to this - it’s probably not clear the way I wrote it, sorry!