[jimmyj]

Hi I am in the process of repairing a stall shower where originally, ceramic tile was installed on water resistant sheetrock.The shower has a fiberglass base which I am going to leave in place.Due to leaks in the bottom part of the shower wall just above the shower base,the sheetrock behind the tiles rotted and disintegrated and needs to be replaced. I am considering replacing the bottom two feet of damaged sheetrock with new ceramic tiles installed on hardie backer board.If what I read is correct I should set the hardie backerboard 1/4 inch above the top of the shower base flange and put some form of waterproof barrior in back of the hardie board. If the above is correct my questions are as follows:
1)should the waterproof barrior material overlap the shower base flange in any way or should it just be cut off at the end of the hardie board?
2)which should I apply between the gap created between the shower base top of flange and where hardie board meet, mastic or silicon.?
3)when I bridge the bottom ceramic tile across the gap beteen the hardie board edge and top surface of shower base flange should I continue with the mastic cement holding the top portion of the tile against the hardie board to the part of the tile where it presses against the inside of the fiberglass base or should I silicone that half? I know you have to leave a small gap of maybe 1/8 inch between the fiberglass base and bottom edge of tile for application of the silicone.
Any help would be much appreciated jim

 

[oh'mike]

What you are describing is a patch job---they seldom look good,or last very long.

However if you can't afford to take out the rest of the walls---here you go.

Peal the tiles one or two rows above the patch area.

Make a nice straight cut into the old green board,all the way around--

Add your new Durrock--use screws----stop the Durrock at the top of the shower pan flange.

Get a roll of tilers mesh (looks like drywall mesh but is alkali resistant.)

Cover the seams and corners with the mesh---Mix a small batch of modified thinset and 'tape' the meshed seams---thin---you don't want a hump.

Paint the new work with Hydroban or Redguard---this will waterproof the rock.

Set your new tile with modified thinset---pack the void at the shower base as you tile that area.

Grout,silicone caulk the corners and pan and call it done.----Mike----