Backer board adhesion?

[TaskBoy]

I have a vertical 7/8 inch deep flat depression along a brick bench. The space to fill is 1 foot high x 16 feet long and I'd like to fill the space with 1/2 inch backer board. Can I do that with just using thinset so I don't have to drill holes into the brick for screws (I doubt I could match up the holes) ? The backer board's bottom edge would rest on the floor. I'm tiling over the backer board. Thanks.

[ChrWright]

Thinset is fine, but screw it as well. Use tap cons which usually come with the proper size masonry bit. Set the board in place and then drill your pilot holes through the board and into the masonry. It will be easier if you hit the mortar joints.

[TaskBoy]

Christopher, thanks. The project has changed a bit. I'm going to cut off that brick sticking out--somehow. I want to avoid a diamond bladed skilsaw due to the nasty dust. Maybe go old school with a brick set chisel?

The advice on the backer board is good as I need to cover the rest of the brick with it due to the brick being painted (can't remove it). I am going to use tapcons with versabond behind then tile with versabond over the backer board.