The farmhouse project has a wetroom rather than a traditional bathroom. The primary difference is that a wetroom is designed and built to get wet – which is not to be confused with a room that is meant to be wet as that would be a swimming pool.

The process begins with a room design with a drain in the floor and a small amount of pitch from all points to the drain. This can be achieved in a number of ways. If the floor is fixed, then the process is to build up the perimeter. If the floor is above grade, the floor can be sunk but this requires alteration to the floor joist construction. In my case, I was building on a concrete slab and had the slope built into the slab when it was poured.

Note: Creating the final floor pitch so early in the construction was both good and bad. It was good in so far as "the floor is the floor". In retrospect, I should have had the floor poured with a shallow void and then sloped the floor when it came time to build the room. This would have given me more control over the slope. As it was, slope was done before there were any walls or other reference points which lead to the slope being off by about 3/8" at the closest wall to the drain plus the drain is off by as much as 15 degrees from level.

Once the room is framed, it can be sheathed in wall board (aka sheet rock) or cement board (such as durarock). The choice is partly yours and partly a factor of how you will waterproof the room. I went for overkill and used cement board and then used Schluter Kerdi for the waterproofing. I found out too late that the manufacturer suggests Kerdi be applied to sheet rock but with a little extra work, it can be installed over cement board. Kerdi is a polyethylene waterproofing membrane with a polyester felting on both sides. It is installed using standard thinset mortar. The felting bonds with the mortar.

Installing a waterproofing membrane with mortar means you are doing the traditional mortar tiling job twice – once to install the membrane to the walls and floor and again to install the tile to the membrane. This means the tiling job gets very big very fast. If you were tiling a typical bathroom floor, you would be looking at 100-150 square feet. The tiling might take 2-3 hours and then the same for the grout. When you add the walls, the area jumps to 400-600 square feet. And, when you consider the waterproofing membrane, you are ostensibly tiling twice so you will cover 800-1200 square feet. That is a lot of work. Plus, for anyone who has never tiled a wall before, mortar and gravity have a way of conspiring against vertical surfaces.

Thus far, the Kerdi has been installed and I am waiting for more mortar (miscalculated somewhere). As you can see, the room is currently orange ! One hint I found for installing Kerdi is to mix the mortar slightly wetter than for tiling. This helps the Kerdi settle into the mortar and it helps with reducing any voids or air pockets between the Kerdi and the wall.

BTW: If you are interested in the easiest way to work with Kerdi membrane, the answer is a rotary cutter. I realize most workshops don’t have a rotary cutter and long board just lying around … but mine does <grin>.