A reader's Miscellaneous question: Leaking shower?

Zeny C,   from   Algester, Qld : Australia   had this Leaking shower question.

Hi Bill
Re: moldy wall
We added a bathroom 4 yrs ago. Now, we noticed the lower part of the adjacent gets big patches of mold indicative of moisture or dampness.
This wall is directly behind the shower of the new bathroom. Should we pry out the shower tiles and seal its wall before refixing the tiles and cut out the wall board of the moldy wall?
Please us with your most needed advice. I tried to apply silicone sealer to the corners and edges of the shower floor but this obviously did not help.

Bill's answer

• Silicone itself does not like sticking to damp surfaces. (unless you use the special one for damp areas, I forget the name now).
• It might be worth a try with something else. The tilers use "Caulk and seal" which is acrylic, (water clean up) which will have a better chance of sticking to the damp surfaces.
• Do all the corner joints, scrape the old stuff out as good as you can. This may help for a while.
• If this doesn't work then you may have to do as you say. Take off the tiles in the shower area and do a proper waterproofing job.
• Make sure that the area you are going to seal is clean, and try to get it as dry as you can before doing the waterproofing membrane.
• It is fairly easy to do, I use a paint roller to put the waterproofing on, and an old 75mm paint brush to lay the fiberglass tape into the corners.
• If you get the wet area fixed correctly, and no more moisture is going through the wall, them maybe the plasterboard on the other side will dry out OK and you may not have to replace it.