Our driveway is sunk maybe 5 feet down from the
level of the front yard, and they're separated by
a rock retaining wall. (Rocks maybe 5 to 10 or 12
inches wide/high, don't know how thick (going back
perpendicular to the wall.)

Anyway, over the years the water pressure (rain)
has, in some places, washed out the concrete or
grout or whatever they used for binding it all
together.

So they're holes between some of the rocks, of
size, at the largest, maybe six inches in both
directions.

Question: what to do about it?

And how much work might it be?

(Something you do yourself, or instead hire
someone? (Here in Westchester County, NY,
just north of the Bronx, there's lots of
(mexican, central-american) immigrants who
seem to know rock-work.))


Ideas welcome!


Oh, whatever you use to fill up the holes,
do you have to make a big deal of mixing it,
or might it come "ready to use"? Pros and cons?



Thanks!


David