Rock WallI have a rock retaining wall that has seen better days. Some day we may replace it, but for now, I would rather try to do some patching to make it more water right and also to fasten the top stones down so they aren't a hazard. It seems like it's meant to be fairly "primitive" looking, so I'm not super concerned that I'll mess up the look of it. I'm more interested in ensuring that I use the right materials & tools to do the work so that it will hold together as long as possible. What type of mortar do we need? Are there any tips or tricks I should know? Thanks!

1 Answer 1


Your “wall” looks more like a “curb” than a wall. I can’t tell from the picture, but it doesn’t look like it’s holding back any dirt (like a retaining wall).

I’d use Type S mortar because it is waterproof (good for exterior use) and has a high strength value. (Type N has a medium strength value.)

When installing the mortar, you don’t need to have a “full bed” to lay the stones into. Because it’s not a retaining wall and because it’s not tall, it doesn’t need a carefully laid depth or consistency…perfect for a DIYer. Just match the stones as close as possible and install the mortar in a pattern that matches the existing mortar joints.

  • Thanks Lee Sam. On the side of the yard, where I took the picture, I would agree that it's not doing much retaining. Down hill towards the house, it's slightly taller and has maybe 18" of dirt up against it, but it doesn't necessarily seem to have lost it's overall integrity, just has pieces falling off here and there. What I'm hoping is we can just over time, work our way down the wall and fix it back up. We only moved into the house 9 months ago, so who knows when there was any work done on this last.
    – John W.
    Jun 7, 2021 at 1:26

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