Replacing the railing on an old rock retaining wall


This house was built in the mid 1950s. I assume the rock wall was built at the same time. It has an old railing that is not attached anymore and needs to be replaced. My current plan is to cut off the old railing and build a wooden post and cable railing.

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This is just an example of what I'm trying to accomplish.

My issue is that I'm not sure how to anchor the posts to the wall.

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Here is the rock wall.

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You can see that the mortar at the top isn't in the greatest of shape.

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The span is about 16 feet total.

The current railing is secured via some odd pieces of rebar and having some of the metal posts mortared in to the wall. The rebar has detached in some places and some of the posts have just broken off, leaving the whole thing just flopping around.

My original plan was to cut the old railing off and get something like these post bases and anchor them directly to the wall using these bolt wedge anchors with some washers or something to shim it to keep the whole thing level.
I've since realized that bolt wedge anchors are probably not a good idea on these stones. I'm also worried that using a hammer drill on this wall will simply knock the rocks loose.

I think I've got a handle on how to build out the railing if I can figure out how to mount the posts to the wall. That's my concern right now. Thanks.

Best Answer

Cut the existing fence out in pieces, preserving as many of its original vertical support posts as you can. Instead of solid 6x6 lumber, use four pieces of 2x4 lumber in a square, and secure them tightly to the original posts. You might also be able to design a special pentagonal support this way that would work well in the middle corner of your wall.

Or if the original support posts are hollow below grade (which is a long shot), cut them off flush, and embed new threaded rod inside them with epoxy.

Anther option is to accept that you're going to damage the wall when putting in new fasteners, and also plan to add a new cap layer to the wall that would cover up that damage. Avoid using high impact hammering, try to find a bit that can grind instead, and use plenty of water to wash it out while drilling.