DryStoneGarden

mongrel stone wall before

old moss rock wall after

Before and after photos of a dry stack wall we recently repaired. The original wall was built about fifty years ago with just a single rock type, and then at some point the red and grey river stones were added, probably during a repair job but also possibly because someone wanted to borrow stones for another one of the walls on the property.

The big issue obviously was the two cedar trees, which had pushed the wall apart and partially swallowed many of the original foundation stones. A few of the stones were literally engulfed by the root/trunk of the trees; we had to leave those embedded stones in place and just stack in front of them. We moved the wall forward six inches, added a gravel foundation and gravel backfill, and scavenged the yard for enough of the original moss rock to restack the wall with a single rock type, discarding the river stones. By the end of the day, we had just a single leftover rock about the size of a softball; every single other moss rock that we could find on the property had been used in the wall. Eventually the trees will push the wall apart again, but then it can be stacked one more time.

Last December we were hired to do a similar repair on another fifty-year-old wall that had been pushed over by a redwood tree. The difference with that wall, though, was that it had been built (poorly) with mortar. To repair that wall, we had to demolish it with hammers and we were unable to salvage almost any of the stone; it was fit only to be re-used as rubble backfill and we had to buy a pallet and a half of new stone. So the repair job became a replacement job. And, of course, it also became much more time-consuming and expensive, taking three times as long and costing four or five times as much money. It’s a big factor to consider in debates about mortar versus dry stack: mortared walls stand up well for a long time, but when they do eventually need repair work, it becomes a much bigger job to repair them and they frequently need to be completely replaced. Dry stack walls do typically need to be repaired more often, but those repairs are also typically much easier and much cheaper over the life of the wall.

ryan 12/7