Kerdi installation instruction ommissions

[Kirk Grodske]

Having viewed the Schutler video on their site and John's ebook, I noticed no one indicated the size hole to make in the subfloor for the drain.

I was fortunate to reach Dave at Tile Experts and he indicated it should be between 4 3/8 and 4 1/2 inches.

I am replacing the entire trap and riser and have the riser "loose" so I can cut it to the finished height once I find out what that is. As I understand it, it will be 2 " from the finished height of the subfloor.

I have reinforced joists and installed 3/4 ply according to the flexometer and previous posts. I will now put down felt, lath and build up my morter bed.

Do I understand correctly that you choose the farthest distance from the drain for the water to travel and then strike a level line from that point all around the shower enclosure? The reason I ask this is, I am making a curbless shower and I have 2 feet in the shower and about 4 feet out of it where the attendent will stand. This area will get a little splash and dripping, but not spray. I have created room for a slope of 1/4 inch in the framing and resultant morter bed, but was not intending on bringing the outside edge dimension into the shower. This would cause me to drop almost an 1 1/2 from the drain to the closest wall which is about 1 foot away. The shower proper is about 3 feet square with the drain off to one side near a corner to avoid it being under the sensitive feet of the homeowner.

There is also a diagonal corner bench built in so putting the drain in the exact center still makes the closest wall less than 12 inches.

I am thinking about creating slopes that radiate out from the drain at 1/4 inch per foot. Since the bench breaks up the perimeter tile heights I don't know that the 1/4 to 1/2 inch tile size difference would be readily apparent. this would make the drain the lowest spot in the floor and water should not pool no matter where it lands.

Kirk

[John Bridge]

Kirk,

Sorry for the ommission. I assumed people would have the drain in hand before they began the installation process. There is a paper template in the box with the drain. We will load the info onto the Kerdi Web site so others won't have the problem.

You don't need to slope the floor outside the shower, but it wouldn't hurt to waterproof it.

Do you mean the center of the drain is only 12 inches from the wall? That's a little tight.