Is Concrete Adhesive In Mortar Ok When Raising Shower Curb To Its Final Height?

[Iggy]

Last night I set the inside and outside tiles of my shower curb, finally! In the liberry article JB wrote:

Now that both sides of the curb are tiled, you can use the top edge of the tiled surfaces to guide you as you smooth off the top of the curb. Smear a little thin set on the dry mortar and add more mortar to the curb, raking the new mortar off flush with the tops of the sides.

In working with concrete such as a slab, or pool plaster, I use a cement adhesive to create a bond between the new and the old concrete. My questions are:

1. Should I pre coat the top of the curb and the back sides of the tiles with concrete adhesive before I apply the layer of thinset and additional mortar on top of that in bringing my curb to the proper elevation?

2. Should I also mix a little of concrete adhesive into the mortar also, as I do when working with concrete? Will the upper insides of the bare tiles adhere to the mortar by themselves without some type of adhesive applied to them and mixed into the mortar? Will it weaken or hurt the curb if I do this?

3. Since I formed my curb a year ago I fergit....this is the same mortar as that used in forming my shower pan, right? I think its called "fat mud"? I guess I can look this one up again...just thot I could save some time.

Thanks, Mike

[John Bridge]

Hi Mike,

I don't like concrete adhesive. Thin set is foolproof. It works every time if you dump the mud on it while it's fresh.

[Iggy]

Hi John,

Thanks. Should I also spread a little thinset on the bare inside uppers of the tile on either side of the curb also to provide adhesion into the mortar as well? Or does the mortar provide adequate adhesive to the bare tile?

[John Bridge]

Yeah, you can put it on the tiles, too. Just keep things nice and neat.

[Iggy]

John, thank you! I will definitely keep it clean, thin and not thick, and keep the thinset away from the spaces between the tiles and the top edges. This definitely makes more sense to me than doing nothing to create a bond between the cementuous materials at the upper part of the curb.