Water ingress - can’t locate

[Timberbubble16]

Hello, hoping someone can offer me some advice as so far we can find water ingress which is coming into our new extension,

I’ve recently had the extension to my house, completed in November. The water ingress that’s problematic is in the newly constructed part of the house.

Above is a flat roof which has SiG Armour guard, I’ve had this checked for leaks and they have confirmed this is fine. I also have no water ingress through my ceiling, it’s coming into the wall cavity and falling to the lowest point which is the bottom of my window, to the left side. It’s affecting the plasterboard on that side.

It’s driving me crazy as I’ve had the flat roof, the cladding, the vent, the window, the flashings and the seals all checked. It cannot be located.

I was hoping if I could post some pictures someone might have experience in this area to point me in the right direction.

Additional info;
- timber frame build
- concrete floor (insulation underneath)
- cladding on timber studs with building paper underneath
- flashings underneath the cladding in the shape of an upstand
- photographs are a mixture of during and post build.

Thanks in advance.

 

[freddiemercurystwin]

Have you got some photos from further away and an arrow pointing to where the damp is appearing?

 

[diy_fun_uk]

Who's checked it, the original contractor or an independent inspector?

 

[Timberbubble16]

The original contractor checked the flat roof section. We also have no leak coming through the ceiling where the flat roof is. It’s as though the water is coming into the cavity.

 

[Timberbubble16]

Thank you.

The ingress is landing at the bottom of the window. When I put my hand under I can feel drips coming from the bottom of the window unit. There is a picture with the wooden cill off too

 

[foxhole]

Cant see how the rain is being deflected over top of window, looks like the top of the window detail is iffy.

 

[diy_fun_uk]

If you have a hose with spray attachment, why not try spraying it over the window to replicate heavy rain? Start off just spraying lower third, see if you get the drips referred to. If not try two thirds up, then if need be from the top of the window. If you get the drips then you know the issue is the window or its installation/surrounding area and you'll also know approx. where the issue is located height wise.

That would at least rule the window and immediate area in/out.

Actually you could try just spraying at window cill height first.