Can you waterproof timber joist.

[Craftycocknet]

Hi.

Im doing a stud wall.
Whats the best product to coat onto timber joists to protect them from water. As the joist are going against an old tiled wall but this is a cold surface which attracts water and so the moisture will touch the joists.

Thanks

P. S tiles cannot be removed. The joists are definitely going onto the wall....

 

[Chalker]

I take it you mean a timber wall is being built?
If you are worried, install a vapour barrier (visqueen etc) between the stud wall and the existing tiled wall.
Then insulate, between the timbers with 50mm kingspan. This will keep the moisture inside the room an detach it from the cold wall.

Or you could install a vapour barrier, fit 2x1 inch battens to the wall vertically and then use 25, or 50mm insulated plasterboard. This will have the same effect as above.

A lot depends on what the wall/ room is going to be used for.

 

[widler]

Glue some dpc on the back of each 3x2 ,