Page 343 - Masonry and Concrete

Masonry Garden Walls

342 CHAPTER NINE

The wall should consist of two rows of large stones with their top
surfaces tilted slightly downward toward the center of the wall so that
they are lower in the middle than at the outside edges. The largest
stones should be used for the first course, not only to create a good
base, but also to avoid lifting and adjusting these heavy pieces at
higher levels. Large stones should form the outside faces of the wall
and smaller stones should be used in the middle. A bond stone that is
the full width of the wall should be placed every 3 or 4 ft. in each
course to tie the two halves of the wall together. Each stone should be
chosen for the best fit, trimming and cutting as necessary to make them
sit firmly in place, and shimming with small pieces of broken stone if
needed. After several courses of stone are laid, the small spaces along
the face of the wall are filled in by hammering in small stones. This
process is called “chinking,” and helps interlock the wall and tilt the
stones inward. The stones in successive courses should overlap the
stones above and below to avoid creating continuous straight vertical
joints and to produce a stronger wall. Ends and corners should be
interlocked to provide stability.
Flat stones of roughly rectangular shape work best for cap stones.
The top course should be as level as possible for the full length of the
wall, and in cold climates, many masons like to set the wall cap in
mortar and fill the joints between cap stones with mortar to keep out
some of the rain and snow. Mortar joints in the wall cap should be con-
vex rather than concave so they will not collect water.

9.6.2 Mortared Stone Wall
Mortared stone walls are laid on concrete footings poured below the
frost line. Rubble stone walls are laid up in much the same way as dry-
stack walls except that the voids and cavities between stones are filled
with mortar instead of stone chips. Walls less than 2 ft. in height
should be 8 in. to 12 in. thick. Walls up to 4 ft. high should be 12 in. to
18 in. thick. Even though mortar provides additional strength for these
walls, the same care should be used in selecting and fitting the stones
together, saving the largest stones for the base course, the squarest ones
for the ends and corners, and the flattest ones for the cap. Stone that is
at least roughly squared on all sides will work better than rounded
fieldstone or river stone or rubble that is too angular or irregular in
shape. Mortared stone walls must have bond stones that extend

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