We have some retaining wall steps that are in dire need of repair. We would like to re-level some of them and re-adhere all of the cap stones so they no longer rock.

Is it possible to create a spacer between the cap stone and the retaining wall block to level the stairs instead of having to dig out the entire step? If so, what would be the best way to create the spacer?

It looks like a previous owner has already done this with some sort of mortar on some stairs. I was thinking after using mortar or a plastic shim as a spacer, then using some polymeric sand to level the step. But then how would I adhere the capstone?

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  • Welcome to DIYSE. Great first post. Please take the tour to learn how we operate.
    – isherwood
    May 27, 2020 at 15:56
  • The ideal would be to raise the front of the riser blocks. Shims would be plainly visible from below. Have you investigated whether they'll lift with a little force?
    – isherwood
    May 27, 2020 at 15:59
  • I have not, but I expected raising the risers to be a pretty heavy lift. I could try to get a pry bar underneath it and then lift. I'm guessing then something like road base would then need to be jammed underneath the block? The way that the stairs were I believe improperly installed, is that the none of the risers sit on the riser block below it. So the nose of a riser could easily sink creating the forward pitch. This may complicate lifting them.
    – Ben
    May 27, 2020 at 16:07
  • I don’t think they were improperly installed just time has taken a toll on them. The cap stones are thick enough that some mortar under the front should fix the slant , I would try and maintain a slight slant so the water runs down the stairs not to the back as that would accelerate any wash out of fill material.
    – Ed Beal
    May 28, 2020 at 14:35
  • Looks like failure of the embankment material to me. Something has clearly caused the risers to tip over.
    – Huesmann
    Jun 25, 2020 at 15:28

2 Answers 2


Trying to quick fix masonry in the pictured condition is most likely not the way to go. Remove the treads and rebuild the the footing under the riser with pea stone, backfill with sand or pea stone and replace the treads. Slanting them downward is not a good idea if you live in a place where water freezes in the winter. If you want to add adhesive between the riser and tread use liquid nails for masonry. I’ve done tons of block stairways, to last they need to be relaid.


Have you thought about forming a new set of concrete steps over the existing? You could lay new stone in the concrete treads to retain some of the original look.

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