I am installing 13" tile by my back door. I installed the hardi and taped. Now I think that if I use a 3/8 trowel, my door may not open! Could I get away with a 3/16?? I think where I went wrong was putting 1/4 under the backer but I had to fill in gaps on a rough sub. I would like to use 3/16. if not, will 1/4 work? Anything bigger will cause door clearance problems. My brother-in-law said I could get away with a thinner bed if I use mastic...any thoughts??

Also, the tape made some speed bumps on the backer. Is this okay or should I sand down? It is thin now....I can see the tape.

 

Before you put down your tile, I'd remove the 1/4" from under the backer and reset the backer. I really don't think the 1/4" is helping that much. The backer will provide a smooth surface over the rough sub, once you apply your thinset to the sub.

 

I have never taped the seams on backerboard on the floor. I know it's recommended but unless the seam falls directly under a tile space I don't see what it accomplishes.

But then, I don't understand why CBU needs to be bedded in thinset. It's screwed to the subfloor with a jillion screws

 

I don't see how the tape made speed bumps if you can see the tape.

No, you need to use the 1/4x3/8x1/4" trowel It'll raise the tile about 3/32" once set.

Ahh..... keep him away from tile work.

* Chandler, I think DJ didn't mean he installed 1/4" board under the cbu, he used a 1/4x1/4" trowel to spread the thin set under the cbu.

Well...... many people that aren't tile setters think the same way. Actually, there are lots of people that charge for installing tiles that don't understand why you need to install ALL backer boards into fresh spread thin set. We can talk about it.

Jaz

 

Not worth the effort. There's nothing to be said that would change either of our opinions.