Installing a Sterling shower receptor in a mortar base
We're working on finishing a basement bathroom. We've purchased a Sterling Ensemble shower unit and tried to install the receptor into a mortar base this evening without success.
The floor we're installing onto is fairly level. When we dry fit the receptor, it only took a pair of shims, one in the upper left and one in the lower right corners of the base to make it feel nice and firm.
I've read that installing the receptor on a mortar base will give the best results, so here's what we tried:
- Mixed up a 60 lb bag of mortar mix and spread it about an inch thick over the entire area of the shower.
- Place the base into the mortar and pressed it down into it.
- Got into the shower base and lightly jumped up/down to try and press it further into the mortar.
As we jumped, the base seemed to rock worse and worse. We we theorized that the mortar was too thick and tried about a layer about 1/2" thick. The results were about the same, as we jumped in the base to press it into the mortar, it seemed to rock worse.
We finally gave up and hosed the mortar off of the base and cleaned it off of the floor and came to ask advice.
Could the mortar have been too dry? The bag said to use a max of 5 quarts of water for a 60 lb bag, and the resultant mortar seemed to behave the way the bag said it should (i.e. stick a 1/2" layer to a vertical trowel and it should stay). It just seemed too thick for the receptor to be able to force it's way through, like trying to push through wet sand.
How much pounding can one of these bases take? Can I use a plastic dead-blow hammer to pound on the base and settle it into the mortar?