On Thu, 05 Nov 2009 19:17:11 -0500, aemeijers
wrote:

EXT wrote:
red wrote:
I'm re-doing a shower using an acrylic/fiberglass base. The
instructions say to put "mortar cement" under the base. Makes sense,
there were lumps of grey rock-like substance under the one I pulled
out. Problem is, I can't translate "mortar cement" into anything I
can buy at HD, etc.

My searches tell me to use the same mortar as laying bricks, or to NOT
use the same stuff, use regular concrete mix, use regular mix with
sand added, don't use regular mix as it will wreck the plastic, etc
etc etc.
I think I know less now than when I started.

Can somebody tell me what it should say on the bag at the building
center? Brand names are fine, if it isn't available around here at
least I can ask for equivalent product.

Thanks,
Red

You are looking for "Thin-set Mortar" and you will find it in the tile
section, as it is used to set tiles.


I'm no expert, but I think not. Thin-set is pretty runny. All the
mortar-bedded shower bases and plastic tubs I ever saw go in were bedded
in plain old mortar mix. You definitely don't want concrete, lest a
stone poking up worry its way through the shower base.

I used thinset, mixed to a "low slump" consistancy and just "worked"
the base in.

ISTR on TOH a year or two back, they showed people using gypcrete, and
even a plastic foam that set up rock hard, instead. It doesn't need that
much strength like a sidewalk would, it is just to keep the shower base
from flexing as people stand and move in it.