142
Molesworth’s pocket-book
Corrugated Iron Roofing.
B. Wire Gauge. Size of Sheets. Weight per square. Sq feet per ton.
feet cwt. qrs. Ibs.
No. 16 . 6 x 2 to 8 x 3 3 0 11 800
„18 .. 6 x 2 to 8 x 3 2 16 1000
.,20 .. 6 x 2 to 8 x 3 1 3 6 1250
„ 22 .. 6 x 2 to 7 x 2i 1 1 7 1550
„ 24 .. 6 x 2 to 7 x 1 0 24 18S0
26 .. 6 x 2 to 7 x 2| 1 0 6 2170
of the weight to be added for lappage.
Sheets should overlap about 6 inches, and be
double riveted at joints.
3 lbs. of rivets required per square of roofing.
Purlins should be about 6 feet apart.
Curved roofs may be made up to 20 feet span
without framing; tie-rods 12 feet apart.
Cukvei) Roufs.
Curved roofs are made up to 30 feet span, with
20 feet radius of 18 B. W. G. corrugated iron
without trusses.
Tie-rods, 2 inches x f inch or 1| diameter,
6 feet 4 inches apart; king-rods f diameter, eaves
stiffened by angle-iron 2| x 2j x j, and top
strengthened by an angle-iron lj“x U x I
running along the under surface of the corrugated
iron on each side of the kiug-iocb.