Water within wall of bay window

[lxand4]

hi
We have recently found water dripping into our lounge from the join at the ceiling at the bay window, we first thought it may have been a leak in the radiator directly upstairs, having taken the floorboards up upstairs the pipes are fine. We then discovered that below the bay window upstairs the wall in very wet! However there isn’t any evidence of this on the bedroom walls, it’s only when you put your hand within the wall, behind the plaster it’s soaked. The two smaller angled walls are worse and the rad sits within the bay, so I’m guessing this is why the biggest wall isn’t as bad (drying it out).
We haven’t really had rain recently for the water to be getting in and there are no pipes in the loft for anything to be leaking down.
Any suggestions???

 

[JohnD]

show us some photos of the bay, from the front and from above.

pay special attention to the lead flashing that prevents rainwater penetration where it joins the house.

Also of the gutter above.

 

[lxand4]

View attachment 156752

View attachment 156754

Hi,
Thanks for responding. I have just taken a few snaps of outside the house and under the boards of upstairs. The black material is wet.

View attachment 156752

 

[lxand4]

Unable to upload more pics of inside

 

[JohnD]

good overhang. So have a look in the loft, and from across the street with binoculars. The water may be leaking through the roof.

there is a possibility of plumbing in the loft.

Can't see your attachment. You can copy and paste pics into your reply.

 

[lxand4]

this is a membrane within the wall, it appears that the other side of this is brick and inside is lost insulation and then plaster. This membrane is wet

 

[JohnD]

that looks like you have some kind of dry lining on the bay. If the water is only seen beneath the window, it might be that rainwater is leaking at the window. But it should be protected by that big roof overhang so I don't see why. If construction is correct then water should be on the outside of that felt or whatever it is.

Have you looked in the loft?

 

[Notch7]

cill drainage issue?

 

[lxand4]

Think we are going to 're seal everything this weekend, strange as this is the first day we have had rain since we noticed the issue. We think it may be a condensation issue. From reading it seems bay windows are notorious for this due to the single skin being colder and meeting the warm house . I wouldn't have expected so much water though. Glad we did discover what seems quite early and damp hasn't filtrated through the walls yet. Especially as we have 8 month old twins! Only been in the house a year too

 

[foxhole]

Windows have no trickle vents?