Pediments

Pediments were originally triangular gables found on Greek and Roman temples. During the Renaissance and subsequent Baroque and Rococo periods, new and more complex shapes were introduced. Regardless of their shape or complexity, pediments remain a low-pitched form.

3a. Height to Width Ratio

A pediment’s height to width ratio depends on its size. Large pediments that are too high can quickly become overpowering and visually too top heavy. Meanwhile, if small pediments do not have enough height, they can appear diminutive. Therefore, as pediments become larger, their height to width ratio should decrease.

Because a pediment’s size is often related to how many columns it has, the following formula can be used to determine an appropriate height for a given width and number of columns:

Height =                4 x Width           
             14 + Number of Columns

The below table has been populated based on the above formula and can be used as a convenient reference.

Number of Columns Height/Width
2 0.25
4 0.22
6 0.20
8 0.18
10 0.16
12 0.15

These ratios represent a best fit taken from multiple pediments. In reality, many existing pediments may be slightly shorter or taller. However, by using these ratios, you can be assured your pediment will have an appropriate pitch.

The six pediments below illustrate these ratios. The images have been sized so that all pediments have the same width.
Left to right top row is: Castle Grove in Ireland, the White House in Washington D.C. and the Athenaeum in Bucharest.
Left to right bottom row is: la Madeleine in Paris, New York County Supreme Court in NYC and Catedral Metropolitana in Buenos Aires.

Pediment Ratios
Pediment Ratios (click to enlarge).

3b. Coupled Columns

Coupled columns count as one column. For example, St. Paul’s pictured below would be considered to have four columns (not eight) and hence use a height to width ratio of approximately 0.22. For more information on coupled columns, see Guideline 2k. Araeosystyle intercolumniation.

St Paul's Cathedral, London
St Paul’s Cathedral, London (click to enlarge).

3c. Inferred Columns

If a pediment does not have actual columns under it, the columns can often be inferred. Take Marble Hill House displayed below for example. The South façade shown on the left does not have columns, yet it is fairly easy to imagine where they would go if there were columns. They would naturally be placed at both ends of the pediment and in between the windows for a total of four columns. Therefore this pediment should have a height to width ratio of approximately 0.22. As can be seen from the North façade shown on the right, there are indeed four columns, placed exactly where we would expect them.

Marble Hill House, Twickenham
Marble Hill House, Twickenham (click to enlarge).

Pediments above doors or windows can be treated similarly. Often they do not have columns supporting them. However, a column on either side of the door or window can be inferred. Therefore for pediments above doors or windows, two columns should be used in the above equation resulting in a height to width ratio of approximately 0.25.

3d. Pediment Variations

The most fundamental variation on the original Greek triangular pediment is the rounded, or segmental, pediment. As illustrated by the Banqueting House below, the height to width ratio is the same for both triangular and segmental pediments. When a row of windows are surmounted by pediments, the pediments may all be the same shape – either all triangular or all segmental. However, it is quite common to alternate between the two forms.

Banqueting House Whitehall, London
Banqueting House Whitehall, London (click to enlarge).

Both triangular and segmental pediments can be varied further by using different options for the apex and base. These options are: standard, receding, and broken (also known as open). All the pediments shown so far have had a standard apex with a standard base. This is the simplest and most common form. However, any combination of apex and base may be used. For example, a pediment might have a broken apex with a standard base, or a recessed apex with a recessed base, or a recessed apex with a broken base. The following table illustrates these combinations.

Pediment Variations
Pediment Variations (click to enlarge).

3e. Raking Cornice

As illustrated below, entablatures can be divided into three main elements: the cornice, frieze, and architrave. The cornice can be further divided into the cyma, corona, and various bed mouldings.

Entablature Elements
Entablature Elements (click to enlarge).

In a pediment, the raking cornice is the cornice set at an angle. Using the NYSE’s pediment as an example below, it can be seen that the corona and bed mouldings should be doubled up and included in both the raking cornice and the horizontal cornice. However, the cyma should not be included in the horizontal cornice of the pediment, but only in the raking cornice.

New York Stock Exchange Pediment
New York Stock Exchange Pediment (click to enlarge).

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8 Comments

  1. Kai
    August 11, 2019
    Reply

    Dear sir,
    I thought that the pediment is the triangular upper part of the FRONT OF A BUILDING in classical style, typically surmounting a portico of columns, but it seems the pediment can be the triangular ornaments above of the windows.
    Am I right? I’m not sure.
    Thank you.

    • Joseph Jutras
      November 13, 2019
      Reply

      Yes, you are correct Kai. The term pediment can be used for both cases.
      Pediments can be the triangular (or rounded) upper part of the front of a building. They can also be the triangular (or rounded) ornament above windows or doors.

  2. Alex
    January 22, 2020
    Reply

    As a student currently at college this site really helped. Thanks. (Moulton college , stonemasonry)

  3. Ben
    June 13, 2021
    Reply

    Hello Joseph, I was wondering if you have examples of a building with a column under the middle of the pediment. Looking for precedent for a project in Annapolis, Maryland (so similar to Georgian style).

    Best I can find is columns under the center of a broken pediment or center of a window in Victorian style. Any help would be appreciated.

    • Joseph Jutras
      June 14, 2021
      Reply

      Thanks for your question Ben!

      It is difficult to find examples of a column under the middle of the pediment simply because this should not be done. There are very few hard, non-negotiable rules in architecture, but I would consider this to be one of them.
      The eye is naturally drawn to the center of a building or sub-mass; even more so when a pediment is used as a focal point. Placing an opening where the eye lingers, as opposed to a wall or column, connects the viewer to the interior and makes the building feel more inviting.

      That being said, I have come across two examples which I still remember as they were so jarring. Vaux le Vicomte’s north façade and Raffles Hotel in Singapore.
      However, these should be viewed not as precedents, but as mistakes to be avoided.

      If you are having difficulty reconciling an even number of columns under the pediment with the building’s layout, just let me know. I would be more than happy to review the plans and offer suggestions.

      Best of luck!

  4. July 21, 2021
    Reply

    Ben,

    I recently saw such a detail on a new apartment building in Southern California and was struck at how odd it looked until I remembered seeing a reconstruction of the Minoan palace in Knossos on Crete. In a time before arches had been invented, they used centered columns to hold up timber lintels which held the stone of the walls.

    • Joseph Jutras
      August 16, 2022
      Reply

      Good observation Gennadi. Some tympanums do indeed contain circles as decorative elements. It also common to see circular windows or clocks.
      Tympanums are a great place to add really any motif or design the architect wishes to. Common uses are: symbolic statuary, coats of arms, geometric shapes, windows, or simply left plain.

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