I mixed up my deck mud, and protected my weep holes, now it was time to actually put down the floor.   I drew a couple guide lines on the walls, and adjusted the drain to the proper height so that I would get the specified 1/4″ per foot slope.  Then I dumped about half of the deck mud into the shower, and got to work, spreading it out and compacting it (using the top of a small sledge hammer) after I got the first half roughly down, I reinforced it with a piece of galvanized metal lathe, and dumped out the rest of the deck mud on top.  The second layer is much more work than the first, since the slope has to be close to perfect so that water actually goes down the drain, as this will be the layer that the tile goes on.  So after an hour or so of leveling, compacting, checking, and leveling I was finally happy with the end result.  I had my wife check and make sure that she couldn’t find any spots where the floor wasn’t sloped towards the drain, and after fixing the one spot she found, I was finished, with a very exhausted arm, after stamping down the mortar for an hour or two.  Happily after letting it dry overnight I was very happy with the result.

The shower drain is a surprisingly complex device consisting of three separate pieces.  the first piece goes under the shower liner, and actually attaches to the drain.  The next is a ring that clamps the liner down on top of first pieces so that no water can get underneath the liner.  This second piece also has a few ‘weep’ holes in it, which are very important, and allow any water that gets to the liner, to actually drain away, and not just be trapped by the third piece.  The third piece is what you actually see, and is threaded into the second and is adjustable in height to match the depth of your base and tile.

The weep holes need to be protected from the mortar, else they would clog and become worthless.  Typically this is done with some pea gravel, or some broken tile or tile spacers.  However when I was ordering my liner cornersI noticed that Noble has a Positive Weep Protector.  Since I didn’t have any pea gravel, or spare tile spacers, and the sharp edges of broken tile scared me, I decided that since it was only a couple of bucks I’d try this out.  Its just a piece of clear plastic, that has ridges in it which would allow any water to flow underneath the mortar and get to the weep holes.  Seems like a good idea, but since I couldn’t find anyone who knew anything about it, I figured just to be on the safe side I’d toss a few tile spacers on top of it, as some added protection.

Today I put down the second layer of deck mud (the first layer, the pre-slope,  goes under the liner) onto the shower floor.  This layer is constructed of a type of mortar that is called “dry-pack” mortar, or deck mud.  There seems to be alot of different opinions on just what this should consist of,  compounded by the fact that nobody seems to sell a pre-mixed deck mud product.  It also seems that there are alot of different things that will work, and they really just vary in how easy they are to get down.  If you use a mix that is too wet, you’ll have a hard time getting it to hold its shape.  If you use a mix that’s too strong, once it dries it will be impossible to knock out any lumps.  If you use a mix with to big an aggregate, you’ll end up with a lumpy floor, and if you use a mix with too much cement, it will shrink when it dries, and could crack. 

Therefore, the best mix is a ratio of 5 parts sand to 1 part cement, mixed to a fairly dry consistency similar to wet sand at the beach.  This won’t be a extremely strong product, but as its just going in the floor of your shower, it doesn’t need to be.  With the high amount of sand in it, it won’t shrink much as it dries, so you don’t have to worry about it cracking, and with just a dry mix its not too difficult to get the proper slope.  For more information, from a tiling expert, check out John Bridge’s page on Deck Mud.