Corrugated iron is used for roofs and sides of buildings. It is usually laid directly upon the purlins in roofs constructed as shown in Figs. 230 and 231, the former being constructed to receive sidings of corrugated iron, while in the latter figure the side walls of the building are brick. Special care must be taken that the projecting edges of the corrugated iron at the eaves and gable ends of the roof are well secured, otherwise the wind will loosen the sheets and fold them up. The corrugations are made of various sizes such as 5-inch, 2 1/2-inch, 1 1/4-inch and 3/4-inch, the measurements always being from A to B in Fig. 232, and the depth being shown by C. The smaller corrugations give a more pleasing appearance, but the larger corrugations are stiffer and will span a greater distance, thereby permitting the purlins to be further apart.

Corrugated Iron Roofing And Siding 0900251

Fig. 229.

Corrugated Iron Roofing And Siding 0900252

Fig. 230.

The thickness of the metal generally used for roofing and siding varies from No. 24 to No. 16 gauge. By actual trial made by The Keystone Bridge Company it was found that corrugated iron No. 20, spanning 6 feet, began to give permanent deflection at a load of 30 lb. per square foot, and that it collapsed with a load of 60 lb. per square foot. The distance between centers of purlins should, therefore, not exceed 6 feet, and preferably be less than this.

Corrugated Iron Roofing And Siding 0900253

Fig. 231.

Corrugated Iron Roofing And Siding 0900254

Fig. 232.

Tables

The following tables will prove of value when desiring any information to which they appertain.

MEASUREMENTS OF CORRUGATED SHEETS Dimensions of Sheets and Corrugations.

Kind of corrugation

Width of corrugation

Depth of corrugation

No. of corrugations to the sheet

Covering width after lapping one corrugation

Width of sheet after corrugated

Length of the longest sheets furnished

5 inch.

5 inch.

1 inch.

6

24 inch.

27 inch.

10 feet.

2 1/2 inch.

2 1/2 inch.

1/2 to 5/8 inch.

10

24 inch.

26 inch.

10 feet.

1 1/4 inch.

1 1/4 inch.

3/8 to 1/2 inch.

19 1/2

24 inch.

26 inch.

10 feet.

3/4 inch.

3/4 inch.

1/4 inch.

34 1/2

25 inch.

26 inch.

8 feet.

RESULTS OF TEST of a corrugated sheet No. 20, 2 feet wide, (1 feet long between supports, loaded uniformly with fire clay.

Load per square foot.

lb.

Deflection at center under load.

Inches.

Permanent Deflection, load removed.

5

1/2

0

10

3/4

0

15

1

0

20

1 1/4

0

25

11/2

0

30

1 7/8

1/8

35

2 1/4

1/2

40

2 5/8

3/4

45

3 1/2

1 1/8

50

4

1 1/2

55

6 1/2

Not noted.

60

Broke down.

" "

The following table shows the distance apart the supports should be for different gauges of corrugated sheets:

Nos. 16 and 18.... 6 to 7 feet apart.

Nos. 20 and 22....4 to 5 feet apart.

No. 24.....2 to 4 feet apart.

No. 28.... 2 feet apart.

The following table is calculated for sheets 30 1/2 inches wide before corrugating.

No. by

Birmingham

Gauge

Thickness

Inch

Weight per square ft.

flat

Weight per square ft.

corrugated

Weight per square of 100 square feet, when laid, allowing 6 inches lap in length and

2 1/2 inches or one corrugation in width of sheet, for sheet lengths of:

Weight per square ft.

flat, galvanized

5 feet

6 feet

7 feet

8 feet

9 feet

10 feet

16

.065

3.61

3.28

365

358

353

350

348

346

2.95

18

.049

1.97

2.48

275

270

267

264

262

261

2.31

20

.035

1.40

1.76

196

192

190

188

186

185

1.74

22

.028

1.12

1.41

156

154

152

150

149

148

1.46

24

.022

.88

1.11

123

121

19

118

117

117

1.22

26

.018

.72

.91

101

99

97

97

96

95

1.06