No. 179. Rusticated Arcade.
Rustication is also used in columns, either square on plan or conforming to the plan of the column.
Its most legitimate employment is in basements and to emphasise the angles of buildings.
Basement
A basement is really a continuous pedestal on which an order rests. It necessarily varies in height according to conditions, thus if its purpose is merely to raise the ground floor it may be no more than three to six feet high, but if it is required to form a storey, it should not exceed the height of the order employed or be less than one half.
The joints of the work in basements are generally accentuated by some form of rustication, and the heights of the horizontal courses should not be less than half a diameter of the column of the order above.
When a high basement is used it is sometimes crowned with a cornice, or more frequently with a slightly projecting facia technically known as a plat-band. In either case, the height should be equal to that of the courses exclusive of moulded edges or chamfers. Also a plinth is placed at the base of the same height as the plat-band or a little more. When a cornice is used the plinth should be moulded and may then exceed the height of the courses.
Attic
An attic storey is sometimes used instead of a second order, and this may vary from one-third to one-tenth the height of the order beneath it.