This section is from the book "Modern Buildings, Their Planning, Construction And Equipment Vol5", by G. A. T. Middleton. Also available from Amazon: Modern Buildings.
In the completion of structures of Classic design a finish is given to the building by a cornice of more or less magnitude. Properly so called, the purely Classic designation would be " entablature," which is divided into cornice, frieze, and architrave.
There is generally a top moulding, known as the cymatium, either ovolo, hollow, or of double curvature, and below this a plane vertical face known as the corona, these two together forming the cornice. The soffit is sunk to form a drip, and is often carried, aesthetically, by modillions or consoles, and always by a bed moulding. The whole is surmounted by a blocking course.
The frieze is usually a plane or convex surface immediately below the bed moulding of the cornice, serving to accentuate the mouldings of the cornice, and acting as a contrast between this and the architrave. It is customary in many cases to ornament the frieze with paterę and carvings, often of very rich design and frequently composed of sculpture.
The architrave of one or more plane faces occurs below the frieze, from which it is separated by a small moulding, often enriched by carving. Fig. 138 roughly indicates the meaning of these terms.
Bands and Strings These are horizontal courses of stonework, usually moulded, projecting from the face of the wall, and serving to demarcate the various storeys of a building. They also protect the immediate joints below, and to this end should be boldly projecting, and with the upper surface splayed to prevent lodgment of water, whilst the lower is undercut or throated to throw off water from the face of the work.
Fig. 139 illustrates some more ordinary forms of Classic strings.
Sometimes the use of corbelling is practised, the intervals between the corbels being arched, and a projecting cornice proper completing the whole, as in Fig. 140.
In Renaissance work parapets frequently take the form of balconies, with broad piers interspersed at regular intervals, as shown in Fig. 141.
Buttresses and attached pilasters and columns are used to strengthen and support walls where concentrated weight or thrust is to be resisted. In most vaulted buildings buttresses are of common use, and are in fact essential, unless the main walls are of such a thickness as to dispense with their employment.
In Classic and Renaissance work, where provision of this nature has to be made, the buttress often takes the form of columns interspersed along the face of the wall, either separated from the main fabric (being connected at the base and caps by the entablature which they support) or as pilasters intimately bonded with the wall throughout their length.
These would naturally follow the general character of the design as to mouldings and proportions. An example of the use of columns as additional supports against thrust may be seen in the full-page drawing of the entrance to dyehouse (see Figs. 129, 130, and 131). Here the thrust due to the dome is* taken up at the salient angles, which are the weakest points of the supporting wall, by the half-round columns which have been introduced to strengthen them at these points.
In columns, the proportions for modern work are similar to those used in ancient Greece and Rome. These proportions are based on the ratio of the lower diameter of the column - measured just above the apophoge, or small curve connecting the shaft to the base - to its height, and vary with each Order, and to a certain extent with the taste of the architect.
Pilasters differ from columns only in plan, being square instead of round in section. Their proportions are much the same as are those of columns of the same Order.
They are employed in halls, churches, etc., to save room, for, being seldom projected more than a quarter of their diameters, they do not occupy the space that a column would do. Their bases and capitals should be similar in profile to the columns of which they form a sequence.
When heavy vaults are introduced into modern churches and cathedrals, wherein clerestories are associated with aisles, the employment of flying buttresses may be required. It is almost impossible to bring such features into line with the requirements of Classic ornamentation, and though examples exist in which it has been done with astonishing success, it is customary to hide them by screens of masonry or some other method.