I used walther strong deck tape last year to good effect. Put it over all the joists and beams and am only a year in but it seems to be keeping everything nice and dry.
You need to investigate further and find out why it's like it before we can help to stop the problem.
I'd start with taking down the wallpaper and go from there.
My best guess would be a ventilation problem but that is just a guess.
Hi Guys,
I have a BT master socket located in the loft where the router/server and other stuff is and have other rooms wired with phone lines but at the moment these other lines just run to the loft.
What is the correct way to hook these all up to the master socket?
They are called a big foot system and mainly used in Canada where they have heavy frosts.
The sonotube (large bog roll) is similar but doesn't have the large footprint at the bottom and are generally used for smaller projects.