Three years ago we had a loose flagstone step reset, and they did a hideous job (big blobs of concrete, stark color contrast).
Now it is completely loose again, and the adjacent stone is starting to loosen, too. There is an underlayer of mortar but the stone was not set into it. There is a thin layer of sand between the mortar and stone. As far as I can tell, the mortar between stones is all that keeps the stone down when you step on the overhang.
That doesn’t make sense to me. Is it possible that the stones were originally embedded in mortar, and the sand was used in later repairs?
There is also a crack through one stone (marked with an arrow) but the bottom half is still firmly attached and I’d rather not dig it out right now.
Is there a DIY fix that will hold for a few years?
Janet
P.S. When I wrote “mortar between the stones,” I meant the stuff like tile grout that touches only the thin edges of the stones.
Replies
The sand you see is just the mortar abraded away from the loose stone.
Chip out the existing mortar under the loose stone, clean everything well, removing any loose material and put it back with "flex" mortar (high acrylic additive content).
That is a lot stickier. You may want to leave the top of the mortar a half inch or so low and point it up with type S to closer match what is there. Flex is darker. Over time it will fade.