Agriculture Reference
In-Depth Information
Figure 87
Close-up of the use
of 'dummy-joints' to
create aesthetic English
quarter-bond to the
central stretcher on a
structurally half-bonded
gauged arch of the
main gateway, Chatham
Dockyard (Kent), 1718.
To create a 'closer', either side of the central header on alternate header
courses, dummy joints were scribed into a stretcher, a quarter brick in from
both ends and parallel to the soffit of the arch at that point (Fig. 87). This was
repeated on the two-brick-deep soffit. These dummy joints, measured at ¼ in
(5mm) depth would have been carefully pointed before the final rubbing-up
phase to complete the overall illusion.
The Straight Arch
It is the 'straight' (also spelt 'strait' or 'streight) or flat arch that comes to mind
when one considers the brick architecture of the Renaissance. It was origin-
ally employed to horizontally span an opening to be stuccoed so creating the
appearance of the stone lintel or beam it was substituting; and can be seen as
such in some of the Roman ruins of Pompeii, Italy. This style of arch became
popular in England at the time of the Anglo-Dutch style of architecture and
craft practices. Moxon emphasises the importance of this form of arch construc-
tion and the related craft knowledge (Moxon, 1703, 279):
But fince streight Arches are much ufed and many Workmen know not the true
way of defcribing them, I fhall write fomething briefly concerning them.
Moxon discusses establishing the skewback, or the inclined surface of brick-
work from which the arch springs. He stresses how the angle may be made
less acute, by dropping the radius, or 'striking point', down the centre line of
the opening, if the width of the piers between openings was two bricks or less
(1703, 279-80):
…Streight Arches are ufed generally over Windows and Doors, according to the
breadth of the Piers between the Windows, fo ought the Skew-back or Sommering
