- Q.I need to secure the base
of a wrought-iron handrail to an exterior granite
landing. My plan is to drill holes into the stone and
use anchors. What's the best way to do this without
cracking the stone, and what should I use for anchors?
I am concerned that wedge anchors might cause
A.Bruce Zaretsky, a
landscape designer and contractor who lives near
Rochester, N.Y., responds: I agree that you
should think twice about using wedge-type or
masonry anchors in this kind of stone. When you
drill and anchor so close to an edge (as you will
when installing a railing), there is a good
possibility that you'll crack the stone or break
off a section.
Instead of anchors, we've had good results using
hydraulic cement, which is a fast-setting cement
product used most often for filling holes in
We drill holes that are as deep as possible and
one size larger than the 9/16-inch- or
1/2-inch-diameter bolts we typically use, fill the
holes with the cement, and then place the rail and
spin the longest bolts possible into the holes.
You'll need to do this quickly, since the cement
will be rock hard in about 10 minutes.
To drill the holes, we normally use a hammer
drill and a bit specified for the material we're
drilling (in most cases, a diamond-tip bit). If
we're worried about cracking the stone, we use a
core drill with a diamond bit, because it doesn't
shake the way a hammer drill does.