Window sill damp

[N8CYL]

HI, the photo attached shows some damp under the old tiles I have just removed . Will this just be a job to check and replace the old mortar on the outside or something worse such as the window itself?
It is North facing and just taken a battering from the snow that we have just had.

Cheers

[J6542]

Do you get a lot of condensation on the window?
If it is not condensation, then you may need to remove the glass unit and see if there is any drainage in the frame or of the drainage is blocked.

[N8CYL]

Hi thank you, this part of the window doesn't open, only the top half opens. No there isn't any condensation
Looking from outside it is sealant between the outside and the inside, could it just be the sealant that needs replacing.

[Skyedriver]

Possibly water getting between glass and frame and into the recess that the glass sits. There should be drainage holes from this channel to the outside, sometimes they get blocked and water fills the recess then leaks into the house. Check when it's raining heavily.

[wolfracesonic]

It looks like your window is sat on a separate cill, something like this…



It could be the cill needs re-sealing where it sits on the masonry: or if the window was not bedded on a bead of silicone where it sits on the cill, in extremis water can be forced under the window and up and over the small upstand you can see in the pic, I saw this happen once, quite impressive! If you try to fix the latter, don’t seal the gap where it says ‘drainage’ in the pic, that gap is to let water out! A thin bead of silicone between the frame and upstand is the best fix you can attempt at this stage.

ETA It could just be condensation, if the window suffer excessively .

Edited by wolfracesonic on Monday 6th January 14:53

[J6542]

Your best bet is leave it to dry, and the next time there is extreme rain (shouldn’t have to wait long) see if you can see any water coming in.
It doesn’t look like it will be caused by the external silicone seal because of where the damp patch is. It’s more likely one of the 3 reasons above.

[N8CYL]

Thank you all. It was extreme weather yesterday. Snow on ledge built up and then wind straight at it with fast thawing.
I'll let dry and monitor.
Cheers