Lived in this house 35 years. Now wife needs a handrail to get up/down front steps. Planning on going with metal railing, 36" high.. Posts are 2x2 with a square bottom flange with four holes for bolts. The manufacturer recommends 3/8" x 4" expansion anchors for attaching posts to the concrete steps.
The problem: A few years ago I overlaid the steps and sidewalk with decorative concrete "stones" which are 11 x 14 x 3 1/2" thick. Two layers. So, the concrete steps are 7" below the surface of the stones. The stones are held in place with construction adhesive, which has been satisfactory so far. But definitely will not hold the stones securely enough to support a handrail. I could use 12" long expansion anchors to penetrate to the concrete steps but they are 3/4" diameter and I'm concerned about the "swiss cheese" effect on the concrete. Alternately, I could use 5/8" x 10" anchors with only 3" in the step concrete, which would probably have enough holding power and slightly less "swiss cheese".
What are the other options for securing the posts, if any? I would be especially interested the approach others have successfully used in a similar situation.