How to Build Capstones on a Cinder Block Wall

Examine the layout of the wall. If it has a right angle in it, you need to cut one edge of the corner capstone with a guillotine splitter. This removes one of the three smooth, machine-cut edges of the capstone and replaces it with a rougher edge that appears more natural. You can rent the guillotine splitter from a stone yard.

Cut the capstones to fit a curved surface if the wall is curved. Lay the first capstone on the wall at one end and place another stone on the wall, keeping the space between the stones slightly smaller than the stones' width. Lay another stone on the edges of the first two stones and trace the edges of the top stone onto the bottom stones. Remove the bottom stones from the wall, and cut them with a diamond blade masonry saw, following the lines. Cut the stones to fit the entire length of the wall by following this technique.

Squeeze a thick bead of masonry adhesive onto the top of the cinder blocks around the holes in the blocks.

Set the first capstone on the end of the wall, with the rough edge facing out and the smooth edges of the stone facing the back and the sides of the wall. Place the capstone so the front edge hangs about an inch over the front of the wall. Press the capstone firmly into the masonry adhesive.

Set the rest of the capstones on top of the cinder blocks, using the same process. Allow the adhesive to set for the time specified on the packaging.