Install the Seat and Face
With all the gussets in place, the crew member spreads thinset for the seat top and face. He spreads thinset on the wall along the tops of the gussets, along with thinset on the tops and faces of each gusset.
Next, he installs the face piece of the shower seat made from the 1/2-inch-thick waterproof wallboard material.
When the face is installed, he spreads thinset on the top edge of the face and drops the shower seat top into place.
Install the Gussets
Waterproofing the Seat