Orders Above Orders
Occasionally in façades orders are used above one another. The Colosseum is an antique Roman example of this, and it was a treatment often adopted by the architects of the early Renaissance. It is desirable that the simpler order should be the lower one. Ionic may be used over Doric, or Corinthian over Ionic.
It is obvious that the central axes of the columns or pilasters of each order used should be in vertical alignment, not only when seen from the front, but in the case of detached columns, from the side view also.
When engaged columns or pilasters are employed, the upper tier may be set back slightly from the face of the lower order which supports it; an example of this is to be found in the Theatre of Marcellus at Rome.
The proportions of the upper order are obtained by making the lower diameter of the upper tier of columns or pilasters equal to the upper diameter of those
No. 172. Order above Order.
of the supporting order, and an effect of continuous tapering is produced.
It is usual to place above the entablature of the lower order a plinth on which the bases of the upper columns rest. The height of the plinth is regulated by the point of view, as its purpose is to display the bases of the imposed order above the projecting cornice. Generally this height will be about half a diameter.
In many historical examples the upper columns are placed on pedestals, but this treatment, although useful when a balcony is desired, is not to be recommended as the extra width and projection which the use of the pedestal entails, gives an appearance of undue weight to be borne by the supporting columns. If balconies are necessary they may terminate with their own pedestals, which can be kept clear of the columns and should not exceed them in projection.