I was hired to tile the floor of a sunroom. The area is 20'x 25' or 500 square feet.
First thing I did was lay down the tile mat. I use the mat instead of backer board becuse one it will flex allowing for slight movement of the floor while the house expands and contracts. Second reason is because it is waterproof. It won't allow the water to reach the sub floor. Unfortunately it worked a little too well.
Whoever built this sunroom needs to be shot. We had a big storm come through during the night and there is a roof leak and as you can see my mat held the water even though I didn't have time to cover all the seems before the storm hit. I got a paniced text message the next morning that there was a lake in her sunroom.
I went and bought some plumbing supplies so I could put a drain in the floor. After locating the best place to install the drain I cut a 3.5" dia hole in the floor.
It drained like this for a good 15 -20 minutes. That's how much water had entered her sunroom during the night.
Now I have to wait for to completely dry before I can finish my work.