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Damp in corners of window

I have recently moved into a property and noticed condensation on DG window in bedroom. No trickle vents or air vents. Discovered damp in loft above which has now been resolved and dehumidifier cleared problem.
Decorated room and after heavy rain, damp patches have appeared in both bottom corners of the wall next to the frame and starts to rise up. I have resealed the silicon inside but no change. Checked the silicon outside and it does not appear to be broken but water must be getting in? Does anyone have an obvious suggestion other than replace all the sealant that I might be missing? Plaster is wet.
Also, paint in top corner of room above window is now wet and after inspection in loft above, plaster above is bone dry so I assume this is a condensation problem.
Will fitting an air vent close to the ceiling help this issue?
Very frustrating as after expensive survey, of course nothing came up

5 Answers from MyBuilder Window & Door Fitters

Best Answer

Depending on window manufacturer there is usually a void outside between the cill and the window if this void isn’t sealed then water can be directed internally in the corners of the plaster areas.
Or when the window is glazed if bridging packers arnt used then water can get trapped and bleed through the beads once frame is full this will be apparent if there is discolouring one the bead seam.


Answered 12th Nov 2019

I would check to see if the cill end caps have be fitted correctly some times fitters cut them short. They should fit to the back of the cill, then a bead of sealant should be applied before fitting to the bottom of the window. concerning the condensation issue. I would have trickle vents fitted this allows circulation of air to help stop the build up of damp.


Answered 12th Nov 2019

This could be a problem with the cavity. If the cavity is bridged with mortar or debris, your outside brick work could be transferring moisture to the inside blockwork. I have seen plasterboard stuck over a cavity with plasterboard adhesive without a cavity closure installed that has caused this same problem.


Answered 12th Nov 2019

Usually this means you have a gap between the frame and brickwork and water is coming through this way or if you have condensation on your glass this sometimes trickles down on the window cill in the corners, Do not seal the gap between the frame and cill this allows water to come out of your frame and soak away down the cill, if the void is sealed it will cause your window to leak internally


Answered 14th Nov 2019

the answer i would say is the water running down felt under tiles on roof above window into soffit then running into room and socking into plaster.have you had new facias and soffits gutter drip ether not on or has rotted of allowing water into soffit hope this helps


Answered 14th Nov 2019

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