Page 106 - Masonry and Concrete

Understanding Masonry
105
UNDERSTANDING MASONRY

stone and the way in which it is used are the most important and most
descriptive kinds of information.

4.5.1 Rubble, Ashlar, and Flagstone
Rubble stone is irregular in size and shape. Fieldstone rubble is har-
vested from fields in its natural form—smooth but irregular and uneven.
Quarried rubble comes from the fragments of stone left over from the
cutting and removal of large slabs from stone quarries. Fieldstone rubble
is weathered on all its surfaces, while quarried rubble has freshly bro-
ken faces which may be sharp and angular (Figure 4-16). Rounded field-
stone and river-washed stone can be hard to work with because the
smooth, curved surfaces make it difficult to stack with stability. Round
or awkwardly shaped rubble can be roughly squared with a hammer to
make it fit together more easily. Quarried rubble is more angular but
may also require trimming with a mason’s hammer for better fit. Rubble
stone can be laid in a number of different patterns, depending on its size
and shape and the desired appearance (Figure 4-17).
Ashlar is a type of cut stone processed at a quarry to produce rela-
tively smooth, flat bedding surfaces that stack easily. Ashlar is generally

FIGURE 4-15A

Cast rubble stone.

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