Purlin-tongued roofs are easy to construct and adapt their structure to buildings with complex floor plans, so that this type of structure is widely used in construction. The intermediate purlins rest on the columns and are the rafter supports. The spacing of the poles is 3,0-5,0 m. The tongs cover the rafters and poles on both sides and are connected to them with nails or screws. The connection of the tongs with the rafters is made dovetail.
Gable roof with purlins and ticks: a) cross-section, b) longitudinal section, c) detail of the rafter support on the birds, which rests not on the ceiling joists, but on the main tie beams, d) details of the connection of the rafters, ticks, post and purlin; 1 — krokiew, 2 - ticks, 3 - purlin, 4 - pole (stool), 5 - truss beam, 6 - bottom purlin, 7 - swords.
When using the attic for utility or residential purposes, there is a need to increase the usable height of the attic. In order not to increase the slope of the roof slope, external walls are made higher by approx. 0,75-1,0 m above the ceiling, the so-called. knee walls. The wall post supports the bottom purlin. Ticks cover the rafter, post and brace, which is additionally introduced, or they may include a rafter and a brace, a rest on the cap.
A single-rope roof truss with diagonals; 1 — krokiew, 2 - brace, 3 - hanger, 4 - truss beam, 5 - purlins: upper, lower, 6 - brick wall, 7 - substring, 8 - cross brace, 9 - purlin, 10 - sword, 11 - stirrup.
Suspension trusses are used above rooms with larger wall spacings above 6.0-8.0 m, when it is not possible to use intermediate supports. Trusses with a single hanger can be used up to a span of approx. 10,0 m, and with a double hanger up to a span of approx. 12,0 m.
The main load-bearing structure of a single-rack truss is a structure made of a floor beam, struts and hanger, and a double-hanger truss from the beam, struts, struts and hangers. Purlins are placed on hangers, on which the rafters rest.
The struts are connected to the beam and hangers on the front notch. There are binders next to the hangers on the truss beam or under the beam on the hanger axis, on which the ceiling joists rest.