When stones of uniform size cannot be cheaply quarried the stone may be used to better advantage in broken ashlar, but it takes longer to build it, and, as a rule, broken ashlar costs considerably more than coursed ashlar. This style of work is generally considered the most pleasing, and, when done with care, makes a very handsome wall, as shown by the half-tone illustration, Fig. 67. It is generally only used for rock-face work. To have the best appearance no horizontal joint should be more than 4 feet long, and several sizes of stone should be used. Broken ashlar can be more quickly laid, and at less expense, if the stone is cut to certain heights in the yard, so that only one end joint need be cut at the building.
Fig. 66. - Broken Ashlar (Three Sizes).
Fig. 67. - Broken Ashlar.
Fig. 68. - Random Coursed Ashlar.
Fig. 65 is made up of stones cut 4, 6, 8, 10, 12 and 14 inches in height, while in Fig. 66 only three sizes of stones have been used. Fig. 65 would probably be the more pleasing of the two if executed.
In specifying broken ashlar the height of the stone to be used should be specified. Broken ashlar is sometimes arranged in courses from 18 to 24 inches high, as in Fig. 68, when it is called random coursed ashlar. It looks very well in piers.
The stones at the corner of a building are called the quoins, and these are often emphasized, as in Figs. 61 and 69. They should always be equal in size to the largest of the stones used in the wall. The stones at the side of a door or window opening are called jambs. Fig. 70 represents cut stone window jambs in a rubble wall. A portion of the jamb stones should extend through the wall to give a good bond.
Fig. 69. - Regular Coursed Ashlar.
In rubble walls the quoins and jambs are often built of brick, as shown in Fig. 62.
All ashlar work should have the bed joints perfectly straight and horizontal, and the vertical joints perfectly plumb, or the appearance will be greatly marred.
Trimmings. - This term is generally used to denote all mouldings, caps, sills and other stonework, except ashlar. The trimmings may be pitched off on their face, but all washes, soffits and jambs should be cut or rubbed.