Loads on buildings may be classed under three general divisions: dead loads, live loads, and snow and wind loads.

Dead Loads

The dead loads consist of the weight of the materials composing the structure. For instance, the brickwork in the walls forms a portion of the dead load upon the footings; the materials in the floors impose a dead load upon the columns, etc. In order to figure the amount of the dead loads on structures and the members therein, the weight of the various materials used must be known, and the following tables will be found useful. (For weights of metals, masonry, woods, etc., see pages 29, 30, and 31.)

Table 1. Approximate Weight Of Building Materials

Material.

Average

Weight. Lb. per Sq. Ft.

Corrugated galvanized iron, No. 20, unboarded

2 1/4

Copper, 16 oz., standing seam ............................

1 1/4

Felt and asphalt, without sheathing...................

2

Glass, 1/8 in. thick......................................

1 3/4

Hemlock sheathing, 1 in, thick.........................

2

Lead, about 1/8 in. thick..........................

6to8

Lath-and-plaster ceiling (ordinary)...................

6to8

Mackite. 1 in. thick, with plaster .......................

10

Neponset roofing felt, 2 layers............................

1/2

Spruce sheathing, 1 in. thick .............................

2 1/2

Slate, 3/16 in. thick, 3 in. double lap......................

6 3/4|

Slate, 1/8 in. thick, 3 in. double lap......................

4 1/2

shingles, 6" x 18", 1/3 to weather.....................

2

Skylight of glass, 3/16 to 1/2 in., including frame...

4 to 10

Slag roof, 4-ply.....................................

4

Tin. IX ...............................................................

3/4

Tiles (plain). 10 1/2"X 6 1/4"X 5/8"- 5 1/4" to weather

18

Tiles (Spanish), 14 1/2" x 10 1/2"-7 1/4" to weather..

8 1/2

White-pine sheathing, 1 in. thick ......................

2 1/2

Yellow-pine sheating 1 in. thick.......................

4

Where only the approximate dead load due to the weight of floor, partition, or roof construction is desired, the following table will be of use. In this table the wooden floors and roof sheathing are taken as 1 in. thick.