Interior corners of window sills wet

[Barn Owl]

We're renovating our cottage and there's a couple of problems we just can't solve. We've got water getting in from the outside and making the corners of our interior walls that join with our windows extremely wet. We've tried replacing the outside sealant, filling in cracks etc and nothing is working. Our new plaster is getting destroyed and we're running out of idea's other than replacing the windows with new ones. Has anyone got any suggestions or had this happen to them?

[raysparx1]

It could be the reveals on the outside need hacking off and redoing, also if it is a stone cottage some of the pointing could need replacing, remember water very rarely comes in where you think it does, the first thing to check is the guttering, if they are slightly blocked and water is coming over the top it will run down the wall like a waterfall, have alook at all of the stonework or if it has been rendered, tap the rendering to see if there is a hollow sound anywhere, Good luck, Ray

[Barn Owl]

Thanks Raysparx1 will give your suggestion a go
Barn Owl

[mrpeter]

Are you sure it is water from the outside? You mention the problem is with 'our windows' (plural) it would seem odd if the problem is at several windows and the cause is from outside unless the whole place needs pointing. Could the problem be a condensation problem especially if the house is not heated very well?

[Barn Owl]

Hi Mrpeter
Thanks for your answer. We do have the problem on several window sills but i'm not convinced its condensation. The more it rains the more water we have, which does suggest the problem is from the outside. The reveals & rendering has been checked and there didn't appear to be a problem, so we are at a bit of loss.

[timeserved]

is it getting wet in the corners at the top of the opening or the bottom?. Does your cottage have cavity walls? It could be that you need cavity trays installed above the affected windows. If it is getting wet at the bottom and not at the top of the opening it is obviously penetrating rain that is causing the problem. As well as checking your gutters and rendering as already pointed out. it may be worth sealing the outside of the openings with troweling mastic rather than window/door sealant. This should be done by removing any loose stuff and forming a fillet using a finger trowel. Replacement windows should not be an option for water getting in unless they are rotten.

[Barn Owl]

Thank you timeserved.
In answer to your question the water is at the bottom of the windows. We have brand new guttering & fascias so we don't think it's a problem from the top of the cottage. I understand the windows which are PVC we're installed about 3 years ago. We have a friend who fits windows and he has already done a check on the reveals and apparently there was no problem. We've also put a waterproofer all around those reveals as well for extra protection. He is going to take one of the windows out to check the drainage situation as apparently that can cause a similar situation.
We are running out of theories so I will happily give your troweling mastic a go & keep you posted.