Queen And Princesses Roofs, With Trussed Apex, Such As In Fig. 81. - Table Of Scantlings Of Timber For Different Spans, From 60 To 90 Feet
Description
This section is from the book "Notes On Building Construction", by Henry Fidler. Also available from Amazon: Notes on building construction.
Queen And Princesses Roofs, With Trussed Apex, Such As In Fig. 81. - Table Of Scantlings Of Timber For Different Spans, From 60 To 90 Feet
Span. | Tie beam, T. | Queen Post, QP. | Princesses, PP. | Principal Rafters, PR. | Straining Beam, SB. | King Post, KP. | Struts, S. | Purlins, P. | Common Rafters, CR. |
65 ft. | 15byl0½ | 8 by 7 | 5by3 | 8 by 7½ | 10½ by 8 | 5by3 | 5 by 3½ | 8¼by5 | 4 by 2 |
70 " | 15 " 11¾ | 9 "6½ | 5 " 3½ | 9 " 7 | 10½ " 9 | 5 " 3½ | 5 " 4 | 8½"5 | 4¼ " 2 |
75 " | 15 " 13¾ | 9 "7½ | 5 " 4 | 9 " 8 | 11¼" 9 | 5 " 4 | 5 " 4½ | 8¾"5 | 4¼ " 2 |
80 " | 16"13 | 9 " 9 | 6 " 4 | 10½ " 9 | 12 " 9 | 6 " 4 | 6 " 3½ | 8¾ " 5¼ | 4½ " 2 |
85 " | 16 " 13½ | 9½ " 9 | 6 "4½ | 12 " 9 | 12¾ " 9 | 6 " 4½ | 6 " 4 | 9 "5¼ | 4¾" 2 |
90 " | 16 " 14 | 10 "9¾ | 6 " 4½ | 13½"10 | 13 "10 | 6 " 4½ | 6 " 4 | 9 " 5i | 5 " 2 |
N.B. - In these Tables the pitch of the roof is supposed to be about 27°; the trusses 10 feet apart. The covering slates and the timber to be good Memel or Riga fir. Inferior timber will require to be of larger dimensions. The scantlings for the tie beams may be considerably reduced when they do not carry ceiling joists. See Seddon's Tables, p. 52.
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