Civil Engineering Reference
In-Depth Information
As can be seen in Figs 5.20a and 5.20b, the positioning and size of openings can signific-
antly affect the cost of constructing trussed rafter attic roofs. Attention is therefore drawn
to the design in Fig. 5.17, which, because it is based on large purlins, allows great freedom
of creating openings of any shape or size between the upper and lower purlin without
structural complications. If a large number of openings, or alternatively extremely large
individual openings are required, then this option is strongly recommended.
