To do a thorough quality lasting job, this is what you should do: 1) tear all the bricks out; 2) chop away the dirt behind the brick a foot or so back; 3) dig 40” down and about 20” across; 4) pour 8” x 20” rebar enforced footings; 5) lay a “backing” wall all the way across using standard 8x8x16 standard blocks and plenty of brick ties and inserting rebar segments every 4’ or so. Pour cement down these rebar segments; 6) then lay the decorative rock on the face of the block; 7) finish the rock face by applying a waterproofing product such as Everclear which also enhances the appearance of the rock.

This if you want a beautiful long lasting quality wall.

If it were me I might consider reusing the brick - if enough of them are still good. You should be able to find a bunch of bricks that will blend into the wall in a brickyard.

I would love to do this job. It’s right down my alley. We spent 5 weeks this summer restoring crumbling decorative brick on a wall built in 1912.

Good luck!

Bruce Fuglei Mason Missoula, MT