Leak above new UPVC window

[rhamson]

Hello all, I'm wondering if anyone can advise how to solve the issue with the new UPVC window in our loft room? After recent stormy weather, we found it had been leaking from above the window on the left hand side, plus a bit of a stain in the middle (see pictures).

The window is located in a dormer covered in lead (c1990 conversion above Edwardian house); as you can see from a picture I took after the old wooden window had been removed, the lead curls around the edges of the gap, and so I'm thinking that maybe the wind is able to drive rain through the gaps where the lead overlaps, which is then directed towards the interior of the house above the window frame. There is another overlap above the centre of the window as well, where the other stain is.

The window company have confirmed that it's all sealed correctly so have said it's not an issue with their installation. However after looking online, I'm wondering if they should have installed drip caps/headers above, as these seem to be absent; I'm guessing it would need to be installed so that it starts up inside the wall just behind the edge of the lead, then down and over the window frame to the outside, in order to direct out any water that flows down behind the lead - which would involve removing the windows again presumably... There is also a second smaller window, so we would need to ask them to redo that one as well.

Is this correct, or any other ideas what would solve this? E.g. sealing up the lead better - the installer thought the lead might have lifted a bit in places, but I feel like there should be a measure in place in the window itself to divert water out again, not just rely on everything above being fine.

Thanks for any help/suggestions!

 

[ronniecabers]

Looks to me like the window is fitted right out level with the outer face of the wall?... so there is no reveal? Looking at your picture of the head , Ivery much suspect water could run down and in, normally i'd expect to see some form of reveal ....even if its only 10-15mm, and then water from above would just drip off the face of the dormer

 

[crank39]

Definitely the top, water doesn't run uphill and if the plaster above the window is getting wet then it's leaking either level with the plaster or above it, agree with Ronnie I'd be looking at that plastic trim and the silicone seal, ideally you need to remove it, check to see if there's a gap between the window and lead, seal it with something suitable for sticking to lead and replace or renew that trim piece and seal it good and proper

 

[foxhole]

The window company have confirmed that it's all sealed correctly so have said it's not an issue with their installation.
Hardly likely to admit they f*cked up , which would appear to be the case .

 

[rhamson]

Looks to me like the window is fitted right out level with the outer face of the wall?... so there is no reveal? Looking at your picture of the head , Ivery much suspect water could run down and in, normally i'd expect to see some form of reveal ....even if its only 10-15mm, and then water from above would just drip off the face of the dormer

Definitely the top, water doesn't run uphill and if the plaster above the window is getting wet then it's leaking either level with the plaster or above it, agree with Ronnie I'd be looking at that plastic trim and the silicone seal, ideally you need to remove it, check to see if there's a gap between the window and lead, seal it with something suitable for sticking to lead and replace or renew that trim piece and seal it good and proper

Thanks for replies! So do you all feel it's more likely to do with how the window is fitted against the lead, rather than my theory about needing a drip cap? It just seems like the rain can potentially get in from above the sealed area and go behind it via the lead, so resealing wouldn't fix that?

The installer already removed the interior trim to check the seal but couldn't see an issue there. Maybe need to check if it's suitable for lead though...

The window company have confirmed that it's all sealed correctly so have said it's not an issue with their installation.
Hardly likely to admit they f*cked up , which would appear to be the case .

They were prepared to admit it could be a seal issue when I first rang up as they said it was probably the seal they needed to fix, but then said that this looked fine after checking in person - hence I'm wondering if there is a different issue they didn't want to admit to!