Had this in my bathroom, fixed as follows:
Remove tiles
Cut out all damaged plasterboard and let the timber dry out.
Replaced plasterboard with Hardibacker cement board using stainless countersunk screws.
Tanked with a Mapei tanking kit for the joints and then sealed the Hardibacker board with the Mapei sealer.
Fitted the sealing kit ( http://www.showersealsdirect.co.uk/seal ... 5-kit.html )
Retiled and grouted.
No sign of any leak after 3 years, thats with a 2 head monsoon power shower.
As has been pointed out the "score and snap" on the cement board doesn't really work. I used a diamond blade to cut mine but was using 8 boards as I had to bring the wall back true due to the moisture damage , had a 25mm run out horizontally between the ends.
HTH,
Jon.
Remove tiles
Cut out all damaged plasterboard and let the timber dry out.
Replaced plasterboard with Hardibacker cement board using stainless countersunk screws.
Tanked with a Mapei tanking kit for the joints and then sealed the Hardibacker board with the Mapei sealer.
Fitted the sealing kit ( http://www.showersealsdirect.co.uk/seal ... 5-kit.html )
Retiled and grouted.
No sign of any leak after 3 years, thats with a 2 head monsoon power shower.
As has been pointed out the "score and snap" on the cement board doesn't really work. I used a diamond blade to cut mine but was using 8 boards as I had to bring the wall back true due to the moisture damage , had a 25mm run out horizontally between the ends.
HTH,
Jon.