Shower Pan; Step One

Do you know what's involved in creating a shower pan where there wasn't one before?  I could have taken the easy route and just bought a prefabricated pan but I didn't want to be standing on plastic.  And besides, the walls were going to be tile so why not the floor too?

You have to have a solid foundation.  In my case, I was dealing with a slab foundation otherwise I would have had to laid out probably a good 1"+ of plywood subflooring and then make accommodations for the drain.

Once you have your subfloor established, then you need to create a sloped cement floor bed on top of the subfloor to facilitate drainage, then cover that with a water proof membrane, cover that with yet another 1-3" of cement upon which the tile is attached.

Quite elaborate but necessary if you want to avoid standing water damage and/or leakage.

Step one:  The slope.
As with any shower, the floor must slope towards the drain or you have a big problem.  The slope is 1/4" drop per 12" of distance.  I set the new drain at 3/4" above the cement floor which means at the farthest outer wall, the rise has to be 1.75".

Easier said than done.  I looked around for one of those kits that you could install on the floor that predetermines the slope in all directions from the drain based on distance.  Well as luck would have it, I couldn't find it ANYWHERE.  So I had to improvise.

I measured and cut four 1x2" strips of wood to be used as 'scree' supports.  Each strip is tapered down at the rate of 1/4" per 12".  The shallow ends fit level with the 3/4" lip of the new floor drain and spread out to the far corners or sides of the stall.  This promotes the necessary slope for water drainage later after the next two layers in the process are laid.

Placing the sticks in place to be used as scree supports, I set about mixing 1 part Portland cement with 5 parts clean sand and then dribbling in water until it had the consistency of damp sand.  Then you just plunk it down and tamping into place and using the scree supports to level out the cement.

 Once screed out and smoothed over, let it dry.

The scree sticks will remain in place as the next layers are installed.  There is no concern about the wood getting wet and/or rotting as they will be beneath the water proof membrane, a topic to be covered in the next couple of postings.