Figuring out the basement bathroom layout happened pretty early on in our project. We needed to know how to route the new sewer system and what drains to put where.

We also learned during the deconstruction process that moisture and water leaks can become a real headache. Bathrooms, in building science terms, are considered wet rooms. There is a whole laundry list of moisture management strategies for bathrooms (or wet rooms) that we researched and wrote about.

Moisture that is not properly managed or contained can lead to sever durability issues and indoor air quality (IAQ) issues, such as mold growth.

One wet room recommendation was to include a floor drain. We actually have two. And no, we don’t have a second one because I am German, but because we opted for a walk-in shower. The concrete floor is already sloped toward the shower drain and floor drain.

Tiles and grout are a good idea on the floor and in the shower area, but they are not water proof. To actually create a water proof environment, it is recommended to use a waterproofing membrane under/behind the tile.

The logical place to start is on the bathroom floor. Whatever membrane we use, we will have to fold it up by a few inches on the walls – walls that are not in place yet.

Well, maybe I should get started on those walls …

Moisture management is often connected to indoor air quality (IAQ). Another moisture management recommendation for wet rooms that helps with the long term IAQ  is to use cement board instead of paperbacked gypsum board (or drywall). Cement board is much more water resistant and less prone to mold growth as it lacks the paper backing component.

The installation involves some puzzling. I have to measure in and cut out holes and openings for the plumbing connections. That took some time, but we got all the openings to fit.

For now I just installed the cement board around the bottom so that we can get started with the water proofing membrane.