Structural Design for Architecture
Where a high quality of finish is required,
timber elements are planed on all four sides
(planed-all-round). This results in a larger
reduction in the cross-sectional dimensions
than occurs with regularising. Where a timber
element has been regularised or planed-all-
round the structural calculations are based on
the modified dimensions.6.6.1.2 Solid timber decking
Timber decking is machine-finished timber of
rectangular cross-section with edges which are
tongued-and-grooved so that boards can be
assembled into a flat deck in which adjacent
elements give each other mutual support (Fig.
6.19). Traditionally, this was produced in small
thicknesses, to span short distances of around
300 mm to 450 mm, and was used in conjunc-
tion with sawn-timber beams (joists) to form
floor or roof decks. The range of thicknesses
has been extended in recent years to allow
wider spacing of beams. (See Table 6.7 and Fig.
6.20.)Fig. 6.19 The tongues and grooves in manufactured
decking elements allow concentrated loads to be distrib-
uted.Table 6.7 Span-load table for tongued and grooved solid timber decking200