taping the backerboard joints [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


View Full Version : taping the backerboard joints

02-22-2008, 01:29 PM
Hello. I am a little new at this so I'm looking for some guidance. I am going to be securing my backerboard to the subfloor this weekend with mortar and the backer screws. When it comes to taping the seams, is there a certain method that should be used? Do you fill the joint first, then put the tape down and then more mortar? Are you supposed to use a different mortar for the seams than for what is used under the backer?

Also, is it okay to do this if we won't be tiling for at least another week?


Sponsored Links

02-22-2008, 02:12 PM
It is much easier to do it while you set the tile, but you can do it beforehand. Unlike a drywall joint, you DON'T want any buildup or the tile won't lay flat. Say NO to speedbumps!

Make sure you're using the alkali resistant stuff made for mortar, and just attach it centered over the joint, then, spread your thinset to set the tile. It may help if you run a damp sponge over it first to wipe any dust off. It should dry very quickly before you can put the tape on (it won't stick if it is wet or very dusty). Use the same thinset you are going to tile with (or to the floor, if that is different). No need to purposely force any extra into that joint if you spread the thinset properly, it will fill up. The tape adds that extra bit of reinforcement to tie the sheets together; you want the whole floor to move as a unit, not individual sheets.