Leak on floorboards in bedroom (bay window)

10 Sep 2008
Reaction score
United Kingdom
Had this leak for about 6 months (i think), when it rains it creates a wet patch on the floorboards just in the bay window in the bedroom.

I have sealed the window outside as best I could, I have also painted the roof sealant on the bay roof, which has felt on it, but these have done nothing. When it doesn't rain!!! the patch drys out.

Today I have tried to put some translutent sealant around the rubeer seal around the double glazed window on the outside. The windows are external glazed been in about 15 years. We have only lived here 18 months. The windows in the bedroom and now the rest of the house are getting condenstation on them in a morning which seems to be getting worst. Fingers crossed...

Wall in bedroom seems ok, no damp patches...

Tiles on front of bay look ok, flashing isn't brillant but sealed and looks ok.

Any help would be appreciated.
Sponsored Links
I had a bay window that leaked like that, it was nowhere where the water ended up, ran along the wood from somewhere then dripped down & fell off the sill.

Can you see where its actually coming in to get to the floorboards?
No, can't see where it's coming in, was going to remove the plasterboard on the internal bay wall in the bedroom to see, but not sure once it is removed it will be much help and it's a messy job. I least I could insulate the wall behind the tiles once I have finished.

Still leak showing after last nights rain so the window seals must be ok.

Not sure what to do next?? any help please
Sponsored Links
Check the flashing / seal under the window sill. The wind may well be driving the rain between the sill and the timber studding.
That looks like its actually coming from behind the plasterboard under the sill, and down the plasterboard back to hit the floorboards then spreading out.

As awbcm says, have a look at the seal at the bottom of the window & under the sill.
Although it could still be from above, is trickling down the side then running along something to get to where it them comes further down, investigations outside are in order.
If you think you may have found the point, hose it down to see :D
You may have this type of situation.

yes, there is nowt worse than horrible brown fancy edging :D
Thanks for all the comments

I have tried to seal the under the sill to the lead flashing but it doesn't seem to solve it. I am waiting for a few dry days so I can then hose it down starting from the bottom.

Do you think the flat roof on the bay could be leaking and running down the window frame column on the bay, i.e where the windows connect together?

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Sponsored Links