137 OF ENGINEERING FOKMULÆ.
Table of Wooden Flooring, Joists, &c.
__________________(Tredgold.)
Length of bear- ing in feet. GlRDEIiS. 10 feet apart, 10 to 12 inch beai- ing on walls. BlNDERfl. 4 to 6 feet apart, 4 to 6 inch bear- ing on walls. Joists. 1 foot apart.
Depth. Breadth Depth. Breadth Depth. Breadth
6 — ■M.*. 6 4 6 2
8 ■— — 7 it 7 2t
10 9 1 8 5 n 2f
12 10 8 9 8 2i
14 11 9 10 6 9 2t
16 12 10 11 6f 101 21
18 12 n 12 1 12 2t
20 13 ii 13 12 3
24 15 12 •
26 16 12 — —.
28 16 13
30 16 14 — — —
Depth.
3*
4
5
6
Ceiling
Joists.
1 foot apart.
Breadth
2
24
2t
. When the bearing of the joists exceeds 8 feet, the
joists should be strutted with a row of struts for
each 4 feet of bearing extra.
For trimming joists, add | of an inch in breadth
to the dimensions of ordinary joists for each joist
supported by the trimmer. ’
Wall plates from x 3 to 7| X 5.
Proportion of Steps in Staircases.
The rise should not be more than 7 inches, nor
less than 5 j inches.
The tread should not be more than 12 inches,
nor less than 9 inches.
A good proportion is
Rise in inches = =---------------
I read m inches
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