62. Formerly glazing was included in the painter's contract, but as it is now usual and more convenient to glaze the sash at the mill when they are made, the glazing is included in the joinery specifications, and is not considered as a separate subdivision of estimating work. This method is followed in the example given hereafter.

In measuring glass, take the dimensions between rabbets each way, when the panes are rectangular; if irregular or circular in form, take the extreme dimensions, and consider the panes rectangular.

Polished plate glass is largely used for store-front windows, and also for glazing window sash in fine work. There are three qualities: French plate, and two grades of American plate, which may be obtained in panes varying in size from 1 inch square to 8 feet wide and 14 feet long. The cost of plate glass is estimated by the aid of a price list which gives the cost of the various sizes. This list remains the same from year to year, and is known as the standard list; the fluctuations are provided for by means of a discount, which is the same for all sizes of glass.

Panes Of Window Glass Per Box

When stained or art glass is used, the specifications generally limit the cost, as the glass is made according to the architect's designs.

Ordinary window or sheet glass is sold by the box, which contains, as nearly as possible, 50 square feet, whatever the size of the glass may be. There are two qualities of ordinary glass, known as single and double thick, the former being about 1/16 inch thick, and the latter nearly 1/8 inch. Single-thick glass should never be used in panes over 24 in. X 24 in. in size.

The foregoing table gives the number of panes of window glass in one box of 50 square feet.