We have a very large (1500mm wide) upvc sash window in our kitchen, and we're having problems with it leaking out from under the interior window cill when there is driving rain (which is quite often here as our house is quite exposed). The whole house had new windows replaced at the same time, but this is the only one that leaks so I don't think its just the driving rain that is the problems as others on the same side of the house are dry. If I turn a hose on the window it leaks within 30 seconds. When opened, there is a lot of water standing in the tray along the bottom inside the cill, though I can't see where its getting into the wall below as this visually looks like a pretty sealed piece of UPVC. I've cleaned out the drip holes but they working fine and water is getting out of them, its just like its too much water for them to cope.
When being closed, the window seems to slightly bow in in the centre - I'm not sure if this is just because it is so large, but it means that I have to lightly push the middle of the window to get into the grove at the bottom when closing it, which you can see here (you can see it's touching in the centre with light showing through at either side if you look closely)
but once its closed, the window seems to be snug, and the locks engage properly.
There are no gaps in the silicone round the edges of the window or anything else obvious. This is the view from the outside looking towards the corner which is leaking.
And this is the interior of the window in the corner where it is leaking (the leak is coming out of the area where the bowl is, just under the window board).
I'm desperate to find out what's going on so it'd be great if anyone could shed some light on any possible issues we haven't noticed. The house has just been rendered, plastered and painted, so I'm really hoping theres a solution that won't involve reinstalling the window and damaging all the new plaster and render. The windows were installed by builders, not a window company, as part of a massive reno and unfortunately we've now fallen out with them due to some issues we've had with their workmanship, so to be honest, its perfectly possible they've done something wrong, but I'm not going to be getting them back to fix it. I had an idea that perhaps a weather strip/drip bar siliconed on along the edge above the exterior cill could be a possible option but maybe I'm barking up the wrong tree?
Thanks
When being closed, the window seems to slightly bow in in the centre - I'm not sure if this is just because it is so large, but it means that I have to lightly push the middle of the window to get into the grove at the bottom when closing it, which you can see here (you can see it's touching in the centre with light showing through at either side if you look closely)
but once its closed, the window seems to be snug, and the locks engage properly.
There are no gaps in the silicone round the edges of the window or anything else obvious. This is the view from the outside looking towards the corner which is leaking.
And this is the interior of the window in the corner where it is leaking (the leak is coming out of the area where the bowl is, just under the window board).
I'm desperate to find out what's going on so it'd be great if anyone could shed some light on any possible issues we haven't noticed. The house has just been rendered, plastered and painted, so I'm really hoping theres a solution that won't involve reinstalling the window and damaging all the new plaster and render. The windows were installed by builders, not a window company, as part of a massive reno and unfortunately we've now fallen out with them due to some issues we've had with their workmanship, so to be honest, its perfectly possible they've done something wrong, but I'm not going to be getting them back to fix it. I had an idea that perhaps a weather strip/drip bar siliconed on along the edge above the exterior cill could be a possible option but maybe I'm barking up the wrong tree?
Thanks
