[Master Brian]

I'm working on adding a bathroom in our basement. The question I have is regarding the shower. The house is a 100yr old house with block foundation, where the shower will go is an area that has been dug out, so a newer block retaining wall has been installed several feet in from the exterior walls. The shower will be in the corner and about 4'x4' in size. The concrete block retaining wall is reinforced with steal and each cell was filled with concrete. This wall only comes up about 4', so I'll have to frame about another 3' on top to reach the ceiling.

My question is what is the best method to prep this area for tile?

1)Do I build the framed wall on top, but set it back enough to place cement board flush with the block and tile directly to the block then to the cement board? I'm actually thinking of building the framed wall back ~12" back from front of concrete so there is a ledge to set stuff on in shower. Plus it would eliminate cracking asking the joint. My neighbor is a brick mason, should I have him put a scratch coat on the block to even it all out? It's pretty even as it is.

2)Do I add cement board directly to the concrete block? What would be the appropriate glue for that? I figured I'd secure it in place with tap con screws.

3)Do I frame a wall up just inside the block and build as if it were on any other floor off the house?

I realize concrete/masonry is porous, so figure the walls and floors need something, but I also don't want to over kill either. FWI....I still have to pour the foor in this area as it's dug up for the plumbing. It's a liner on the floor absolutely necessary or is there a way to go without?

As it stands I need to frame about 1/4 of a wall and the jams for the door, but if I am better off with concrete block I can have neighbor add block to the ceiling height. And do the jamb sides with block. I see public showers at gyms, lake, etc and they seem to be just concrete and tile and they get heavy use, so I'm thinking a liner might not be necessary.

Thoughts, feedback on this?

 

[oh'mike]

If you have room, frame up a new stud wall--this will avoid the shifting and cracking that might occur where the masonry wall meets the knee wall on top of it--

You will not be attaching durock to the masonry---tile directly on that--if you don't build a new stud wall.

Also---insulate the new wall---tile on a foundation in Kansas might make for a cold shower stall.

 

[cleveman]

Sounds like this shower area is set up within the basement area, not touching the exterior walls and the floor has been cut out to put a drain/pan in.

You might do well by looking into the Laticrete drain system. There is a nice video on it on their site. This will answer your question regarding if a liner is necessary.

You may have the opportunity to have a curbless shower.

If you have concrete block walls, why not just extend these to the ceiling?

 

[Master Brian]

Another thing to consider is we have been experiencing earthquakes in our area. As of now, they are primarily about 60-100 miles south of where I am located, but the rumbling is still felt where I am located and there are people getting some minor damage such as cracked walls, etc...

Does that affect the best practice in this situation?

As for the rest:
- The block wall isn't really an exterior wall per say, but two of the walls are on a corner. The new block wall is about 1-2' in from where the original block foundation is, so only the last course or two of block on the new wall is at the same elevation as the foundation. The new wall is about 6-7 courses high. Also, realize that the original foundation, for this portion of the house, is only about 12" tall, so it doesn't go below the frost line. With that said I'd assume it is possible on a really, really cold day the soil next to the lower, newer wall could still get cold and transfer that cold into the house. Everywhere else I am attaching rigid foam board, sealing the seems and then insulating with bat insulation in the stud wall built in front of it. If I decide to insulate the walls in the shower, I'd likely use cellulose since it is a little better at handling moisture if any were to transfer through due to condensation or such. Doubt that would happen, but on a small scale it is easy enough to do with the equipment I have and I actually like the cellulose better.

With that said I am currently debating the location of the shower. I might move it just south of where I was thinking and thus only have one exterior wall to contend with.

- If I decide it's ok to tile directly to the block, I'll have the block walls go as high as possible. I actually like this idea as it might also be the best place to double as a safe area during tornado season. At least I'd like to think a concrete/steal reinforced block shower enclosure should be pretty darn safe as opposed to just out in the open of the basement! Hmmm....

- I've looked at the Laticrete drain system and will study it some more. I'm sure the video will say why I need a liner....I may have seen it before, which is why I'm asking again. I'll go watch it again.

- I'd love to do a curbless shower. I'm also debating installing floor drain in the back part of this bathroom across from the shower, I guess if I did curbless there wouldn't be much reason.

I'll see about getting a diagram up and or some pics. I still have a ways to go before I'm ready to complete the shower, but I have to work it through in my mind to make certain I get it right and the way I want it. I'd also love to pour the slab where the shower might go sooner than later, which means I need to figure out how and where I'm locating the drain.