DIY Doctor UK DIY Forums

Damp appearing around this sliding door top corner. New extension built just 3 years ago - cavity wall with render top half and slate cladding bottom half.

Previously been fine and signed off by building control etc.

There is a bath in the room above this area but it’s not been used for many months.

We have no idea as to the cause of this issue. Could it be the roof but can’t see any obvious cracked tiles.

Advice would be v much appreciated as causing a lot of stress.
Thanks in advance

Hi eddieboy,
Given the location of the damp, do you know whether a cavity tray was fitted above the window?
Regards S

Thanks for your reply. Yes a cavity tray is above the door. I’ve had the builder look at it today. He reckons rainwater might be getting in behind the slate cladding and building up. Going to try and silicone along the top of the line of slate and fingers crossed that might help. Any other suggestions? Thanks

Hi eddieboy,
I’m not sure how your builder checked the tray since it is located inside the walls. I cannot see any weep holes above the door - may be worth checking.
Regards S