Fig. 3.
Rough Rubble—trowled
joints
| Fig. 4. | Fig. 5. | |
| Rough Rubble, or ledged work Raked Joints. | Cobweb Rubble—tooled joints—no spalls |
A softer stone, which can be dressed with the hammer, may be treated in two different ways: It may be shaped to fit closely, without using any spalls to fill up the interstices, and, thus, appear as a cut-out puzzle; this is called “cobweb rubble.” However, the more dignified treatment is the squared, uncoursed rubble, in which the blocks are cut to rectangular shape and the joints pointed with a tool. [Figures 5] and [6] illustrate these.
A wall built entirely of field stone depends upon the mortar for its strength. It appears the best when the joints of the surface are raked out, permitting a large part of the stones to project outward. [Figure 7] illustrates this kind of rubble wall.
When the rubble wall is built with very carefully squared stones, and in regular courses, it partakes more of the monumental character of ashlar work and draws away from the rustic value of rubble. In determining the amount of cutting which is to be done, the character of the building should be considered, remembering that the smoother and more finished the wall, the more monumental is its appearance.
