[foothill]

We're preparing to tile our shower/tub surround. I'll be removing existing cultured marble wall panels and removing the existing lathboard and plaster to a height of 5 feet above the tub. The plaster walls are about 3/4 inch or slightly more in thickness. I can buy cement board in 5/8 thickness. I'm planning to lay felt building paper over the bare studs and shim them with carboard drywall shims to match the plaster thickness. I'm thinking the shims will go under the felt paper and should do the job. Do you agree? Would 1/4 inch lattice under 1/2 inch cement board be more reliable?

At the cement board/cement board joints I want to finish with mesh tape and thinset and where the cement board meets existing plaster the plan is to finish the joint with mesh tape and drywall setting compound which I've been told will also support tile. Any suggestions?

Thank you for sharing your experience and expertise.

 

[Paragon]

Foothill,

I use 6 mil vapor barrier instead of tar paper/ builders felt it is just my personal preference as I can cover the entire wall with no breaks in the vapor barrier. The staples will penetrate the vapor barrier and so if need be you can tape the stud lines with a exterior grade tape that is designed for taping house wrap but is not necessary.

You can then apply your lath to the walls to fir these out as I am assuming your intent is to get over the tile flange of the tub with the cement board? Also, if you are tiling I would make sure that I set the cement board at a height so that the last course of tile goes over the edge of the joint. This way you ensure that the seam is covered by something less permeable than paint and you don't have to worry about finishing the joint so neatly and the finish edge of the tile falls on the painted wall and looks attractive.

I would use the lattice or lathe and am not familiar with the cardboard drywall shims you referenced. However I would stay away from any kind of "spongy" backing materials as you want that wall to be solid to avoid any kind of movement that will deteriorate your wall. Also I always caulk my expansion joints where I may get movement such as the corners. I do not grout these corners and the corners I have seen grouted over time cracks and open up introducing a possible water source more significant that what would usually be introduced through the grout lines. You can also get some corner strips made by Schluter but the final appearance of the project is up to your determination.

Good luck and be safe!

 

[foothill]

Great advice! I sincerely appreciate it. Have a nice weekend.:yes:

 

[foothill]

A quick followup. My purpose in using the 1/4 inch lath strips under the cement board is two fold: to get over the tub flange with the cement board and also to put the surface of the 1/2 inch cement board in the same vertical plane as the surface of my (approx.) 3/4 inch plaster wall above. I am only planning to tile to a height of 5 feet above the tub flange.

In pricing out the 1/4 inch lath strips at Home Depot today I discovered that at 64 cents a running foot, it would be cheaper to just use 1/4 inch cement board under the 1/2 inch cement board and I am sure it would be stiffer as well.

Any drawbacks and pitfalls to sandwiching a sheet of 1/2 inch on top of 1/4 inch? I'll use the 1 5/8 inch screws for adequate penetration. Would you tack the 1/4 inch board to the studs with a screw in each corner and the lay the 1/2 inch on top and run the screws every 8 inches through the two sheets?

As Paragon notes I want to set the cement board at a height so that the last course of tile goes over the edge of the cement board/plaster joint so I may need to shim another 1/16 or 1/8 inch at the stud facings after all. I haven't seen wood lattice that thin so I may be forced to resort to the cardboard drywall shims for that purpose.

All suggestions and observations are welcomed. Thanks in advance.

 

[Ikehater]

Lathe Strips

Home Depot sells 3/16" pressure treated lattice strips in their exterior decking dept for $.99/ 8ft strip. I've used these to true up & shim walls for drywall and I expect to use them in my current shower project. Perhaps this will get you close enough. If not, make your own by ripping a 2X4 with a table saw.

 

[foothill]

Ikehater,
Thanks for the info. Like a dummy I was looking at the finish grade lattice in the moulding department. 99 cents for 8 feet is more like it.