This section is from the book "Modern Buildings, Their Planning, Construction And Equipment Vol2", by G. A. T. Middleton. Also available from Amazon: Modern Buildings.
Deduct Facings, same dimensions as last.
Add Facings for reveals the width by the height of reveals.
Measure per foot super. as extra only on common brickwork. Take the height of the voussoirs by the mean length between the intrados and extrados; then take the soffite, its width by its length.
Take the same dimensions as for the face of the arch.
Measure per fool run.
Measure per foot super. to soffites exceeding 9 inches, and per foot run to those not exceeding 9 inches in width. State the kind of soffite, whether segmental, semicircular, etc.; and that it includes the necessary strutting. Keep centering to gauged arches separate, and describe it as close boarded.
Number and bill under the Facings.
For double hung sashes add 9 inches to the width and 3 inches to the height, and for solid frames add 4 1/2 inches, to the width and 3 inches to the height of the deduction of external reveals.
Measure per foot cube.
Number, and describe as "Extra labour, cutting and waste" to rough segmental (or as the case may be) relieving arch, stating the height, width of soffite, and clear span. These may be averaged on the Abstract.