Get Your House Right: Engaged Columns and Pilasters
By Marianne Cusato, Richard Sammons and Ben Pentreath
A column is a freestanding round shaft. A square column
is called a pier. When a round column is attached to a wall, it is called
an engaged column; and when a pier is attached to a wall, it is called
a pilaster. (When a piece of wall breaks forward without any differing
details, it is called an anta.)
Engaged columns and pilasters are used to provide articulation to the
orders in practical use. An entablature supported by a freestanding column
will invariably need to meet the main walls of your building, and it is
here that engaged columns and pilasters come into play. It doesn't look
good to let the entablature just run into the wall. It needs some form
of visual support at the junction. This could be in the form of a simple
bracket, often based on the capital of the column. But more typically,
a full-length column is used to provide visual support all the way to
Engaged Columns: Don't Use Half a Column
The details for setting out your capital, base and taper are exactly the
same as for the freestanding column. There is only one new rule you need
to follow. Never use a half-column attached to the wall. It will look
insubstantial, as if the wall has "swallowed" the column.
Instead, always set the column between 5/8 and 3/4 diameters from the
wall (see Figure 1). The correct example shows how you will see the diameter
of the column expressed. The small difference in plan will have a considerable
effect in three dimensions. The shadow line behind the column provides
definition and a sense of seeing the column as an object in the round.
Pilasters: Don't Make Them Too Deep
Pilasters, by contrast, can appear too large if they project too far.
It is a common mistake to set the pilaster projection at half its width,
as shown in Figure 2, left. Avoid doing this, the pilaster projection
should be proportioned at between 1/5 - 1/4 width (see Figure 2, right).