Help what do I do with this on my window ledge

Jodiehx91

Beginning of winter we noticed that our window ledge in the corner became raised with a bumpy texture we put a screw in to see whether the wood was damp but couldnt really tell I marked around the area and it seems to have stayed the same up until this week I noticed it had got larger. I have pulled some of the paint of and this is what is underneath. 

Can anyone help and point me in the direction of what to do/what could be causing it? 

We have vents at our window and I also have one of them humidifier boxes on the ledge also. There’s no marks in and of the walls at either side or underneath it just appears to be the ledge. 

Any advice would be appreciated.

Bigphil1474

Difficult to say. Is there anything under this shelf or is it atop the window brickwork? Does look like it could be damp from somewhere (maybe damaged external sealant to window letting a bit of water in in that area?), but I think i would strip the wood completely and see what it looks like then.

Jodiehx91

It’s a new build so probably built on nothing 🤣. 

The window is in the alcove of our bedroom the radiator is on the wall that’s underneath the window ledge. It only appears to be in one corner of the ledge the rest of it is fine I contacted a window fitter when it started to raise and bubble and they just said that could be from condensation inside the windows and never actually checked anything else now it’s got worse I don’t know if this could be the problem when I’ve put the things in place to  try prevent the condensation. Will have to strip it back and see what damage is for the rest. 

stuart45

Stripping the paint back to see the whole area of damp is the best idea. It's possible that moisture is tracking in from outside.

twopenny

My first thought was condensation.

Do you have heavy curtains there?

I have a similar bay and windowsill north/east facing and come winter mostly the condensation from sleeping/cold glass tends to cause black mildew on the sealant and a little on the paintwork.

My neighbour has the same layout and the same problem.

Those with living rooms facing the same direction don't get the problem.

I scrubbed and took the sealant out, rubbed down, replaced sealant carefully and repainted. Now it's stayed clean.

But I'd check the outside sealant too.

Martyn_H

As it's a new build, is your house still under guarantee?