I'm a little worried about the edges of the cap stones, I think they should be undercut a little so the water drips off the edge, rather than runs under and down the wall. On the other hand, the mortar should be water resistant enough that it should be tight even if the water is running down the wall.
I'd adapt a wait-and-see position. In the next heavy rain, take a flashlight and an umbrella and see where the water's going. |