In course of constructing my shower pan, I realized I would need to add a fourth 2x4 to my shower curb. This addition was to accommodate the need for an exceptionally thick mortar bed (drain located at the end of a 60" shower). Anyway, the new curb height is now slightly above the screws securing my Hardie Backer to the wall opposite the curb. The final bed is already placed, so I'm wondering if I'm in trouble.

On a different note, I put some small gouges in the bed (1/16" to 1/8" in depth) when I tried to sweep off some residual sand on the surface. Should I take any steps to repair the gouges? Will the thin-set application resolve the problem?

Thanks,

Ben

Hi Ben:

How did you TEST your shower pan.. You did test the pan and connections before pouring the floor... yes? Let me know.. ok.

In terms of the issue you raised with screws... at this point I think you'll be fine. It is not IDEAL... but as long as screws aren't below the floor/tile level you should have no leaks.

Unless, of course, shower drain backs up and the entire shower fills up with water to the threshold height and then you may have an issue. But just don't let that happen and you'll be fine!

The gouges in the floor... no issue at all! The mortar will fill these gaps fine!

Let me know about the pan test.

Thanks... MARK

Thin set will fill in gouges. Coat nail heads with construction adhesive just as a precaution. Thin set of wall tiles should seal but thin coat of adhesive won't hurt. Water should never reach that height anyway.

Hi Mark

Mark,

Thanks for the input. I filled the pan with water overnight just to make sure I hadn't punctured it. This was before I cut the hole for the drain. I didn't use a test plug to check my caulk job around the drain, but it was pretty well coated. Thanks for the feedback.

Harold,

I used CBU screws to secure the hardibacker and some of them are slightly covered by the mortar bed (I have a pretty aggressive slope, which is necessary for pebble tile). At any rate, I was thinking I might be able to shoot some caulk between the CBU and the stud after I tear off the sheathing on the exterior wall. What do you think?

I wouldn't think caulking on the exterior side would help.

I'm a little confused. Do you have screws below the top of the threshold, or below the top of the cement base?

If you have screws at or below the top of the base I think I would seal the joint between the base and the wall with either silicone or Liquid nails (love that stuff, it holds my truck together). You shouldn't have any water getting through the base material to the screw but some could find its way through the joint if settleing or shifting occurs later.

The thin set or adhesive of the tiling the floor and walls should seal that joint however. The silicone or construction adhesive would just be something you can do for insurance. I wouldn't be at all uncomfortable with screws below the mortor bed if the joints between the bed and the walls are sealed with a thick application of adhesive or silicone about 1/2 to 3/4" wide. Don't make it thick enough to screw up tileing.

I have a jetted tub intended to be set in a deck installed in an alcove like a regular tub. Because it's a deck tub it does not have the lip for the walls like a regular tub. I set the cement board of the walls in a bed of construction adhesive on top of the tub deck, I coated the back side of the joint in the wall interior with thick coat of adhesive. Making the outer wall of the tub and cement board one continious surface. Haven't had a problem in 16 years.