The joints of the material used must necessarily be considered, and when plain piers or plain wall surfaces occur the joints may readily be accentuated and so turned to decorative account. The edges of the stones forming the separate courses may be chamfered or moulded. The joints may also be worked so as to form a square recess.
TYPES OF RUSTICATION
No. 178. Rustication.
The surface of the stone is sometimes roughly tooled or frosted, or worked in an arbitrary pattern, which is termed “vermiculated.” This treatment probably gave rise to the word rustication.
When rusticated work is used with an order the height of each course of stone should not be less than half a diameter, and when square recessed joints are used they can be one-eighth or one-tenth the height of the course.
Occasionally only the horizontal courses are thus marked, and this has been objected to as producing a boarded appearance, though undoubtedly the horizontal effect is at times agreeably in contrast to the vertical features. A much more usual treatment in Renaissance examples was to emphasise the vertical joints also.
The length of each stone should be from one and a half to three times the height.
Rustication may be used in the formation of the arch, which frequently has at its springing line a slightly projecting course, in which the vertical joints are not emphasised.