Shower Curb out of cement board

[catslikemice]

Could someone please advise on the best manner to build a shower curb out of cement board. I know this forum advises a mortar and metal lathe curb, yes, I've been the the Liberry, but my contractor wants to use cement board. He thinks it should be ok to nail thru the membrane to attach the cement board to the 2x4's, which I think would be the weakness with this plan.

The preslope is poured and we'll be installing the liner and doing a pan test tomorrow so I need good advice fast.

Thanks!

Vicki

[Westie]

Putting nails in the liner is OK only in one condition : If you want it to leak.

[Mike2]

Hi Vicki.

Just as you suspect, that be one big no-no, Seriously, if that is what your contractor wants to do it might be time to get another contractor. Not only would nailing CBU onto the curb, penetrating the liner be one big mistake, it's most likely just one of a series of mistakes this person would make, or has made.

[Rd Tile]

I shouldn't be telling you this, the tile police will lock me up, I did it a few times on repairs only, not when installing new, so this guy should be replaced, I installed Redgard waterproofing over the whole curb after the backerboard, but I guess water can still wick up from beneath to the nails, doubt that would happen if the reat of the pan is installed correctly though.

[catslikemice]

So I could sleep last night, I made a flying trip to HD to purchase lathe so we would have it for today (sneaky, eh?). Still didn't sleep well but did tell contractor this morning that I didn't want nails thru the membrane in the curb. He was very understanding. Contractor said he would go to HD to pick up lathe, so then I came clean and told him that I picked some up last night and it's in my van.

[catslikemice]

Hi! Follow up and questions....

Contractor formed curb with lathe (with no nails in curb), poured deck mud and formed curb with mud. He followed ratios/recipe for deck and curb mud, especially the physical descriptions of how both should clump and behave to determine how much water to add, but they both seemed a little too wet when applied. Curb was formed but I can see the top outline of the lathe thru the mud in some places.

Questions...

Regarding deck mud being a little too wet....other than taking a long time to dry, what are the problems that could come out of this.

What's the best plan of action on the curb. Is this curb ok to tile or should he come back on Monday and add another layer to cover lathe? If so, please describe bond needed between layers.

This guy is really good, very patient and is following all the advice in the liberry. We have a long history...he built my husband's office, has built a couple hotels...but his projects have been so big that alot of this specialized stuff has been subcontracted out. He's doing my "small" (not small to me or my pocket book!) remodeling project and has been wonderful about my request for this shower curb to be built in this manner.

[Steven Hauser]

Hi there,

To me its too early to rate. It may be fine once it cures. Did he use nails on the exterior of the shower curb?

Yes...lathe was secured to outside of curb.

[catslikemice]

Yes, from catslikemice...my kids must have logged me off!

V

[catslikemice]

Enjoy your turkey, football and weekend of R&R, you tile professionals, but I'll be looking forward to your expert advice on my shower curb and posted photo.

Many thanks in advance to your replies.

V

[LonnythePlumber]

If he's nailing on the outside of the curb I would project the tilers would consider that acceptable. Nailing inside is

[John Bridge]

I think it's about time to back off and let the guy do his work.

[catslikemice]

Hey John, thanks for your blessing on my shower curb!

V

[hammerhead]

There is one other option that I haven't seen mentioned. It's a preformed curb made by either Bonsal or Noble Co. I use it all the time. Nail your 3 2x4 to the floor, do the preslope, liner, and slide this baby over the curb area and nail the outside only, final mud bed, and tile away. Saves me a lot of time. Folks like JB wouldn't dare touch one of these, I'm sure.

[webmastercts]

I have one of those curbs and I am about to install it but I am concerned about the strength of it.... it seems like a hard compressed styrofoam and I can't imagine what would happen if someone stepped on the tiled curb once finished. Of course thinset underneath the curb and on top may be the solution to giving this curb firmness.

i do like the product though and great for rookies like myself.

Is this true that the thinset will stiffen it up a bit...