The purlins are treated with an antiseptic,

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Purlins are made with a cross-section of 160X140 or 160X170 mm. If the rafters are located close together or the walls are made of weak materials, then the purlins are laid along the entire parameter of the building walls. If the rafters are located sparsely, separate short pieces 600-800 mm long are laid.
and insulation made of rolled material is laid between them and the stonework of the wall. To enable inspection and repair of the roof at the eaves, the lower surface of the purlins should be at least 40 cm from the top of the attic floor.

The ends of the rafter legs, every other one, must chile mobile database fastened to the wall (to prevent the roof from being torn off by the wind) with twists of wire 3-4 mm in diameter, which are tied to crutches driven into the wall.

To fasten the sheathing boards or roof decking laid along the lower edge of the roof, short pieces of boards on the edge, called fillies, are sewn to the end of the rafter legs. The fillies are embedded in the cornice masonry or laid over the cornice part of the wall.
When the length of the rafter legs exceeds 6 m, to avoid their significant deflection, it is necessary to install braces (Fig. 123, b).
If the building has internal supports, their upper ends are brought out to the attic, and racks are installed on them along the sleepers. Purlins are laid along the racks, on which the rafter legs rest (Fig. 123, c and d).

The design of the rafters with two rows of internal supports is shown in Fig. 123, d. Here, to absorb the horizontal components of the forces transmitted by the struts, spacers are placed between the sleepers. Fig. 125 shows the details of the assemblies of wooden beam rafters. All rafter joints are reinforced with metal fasteners: bolts, brackets, nails.

The rafters of a gable roof (Fig. 123, e-z) rest with their lower ends on the purlin beams, and with their upper ends on a horizontal beam called the upper (ridge) purlin.

The upper purlin is supported by posts installed on internal supports. The distance between the posts supporting the ridge purlins is taken from 3 to 5 m.
To reduce the cross-section of the ridge purlins and increase the longitudinal rigidity of the rafter structure, paired longitudinal struts are installed, located at each post or (for small spans) every other one (see Fig. 124).