I make the seats between 16 and 18 inches off the finished tile floor. The depth should be at least 14 inches.

Make sure you slope the top into the shower -- about 3/8 in. in 14 inches works well.

I build the seats completely out of masonry materials -- bricks, blocks, etc. The seat is not attached to the walls, per se. It abuts the walls, but sits in the shower like a monument, completely inside the shower pan. Any leaks will go down the drain weep holes.

• John Bridge Services