Purlins are placed on inner walls or gables as supports, or used to support roof steel plates and provide lateral support for steel beams.
Roofing base is a wood base that undertakes roofing tiles, which is composed of rafters, kanban, flying rafters, cornices, tiles and other components.
The wooden frame of a house consists of five parts: columns, beams, purlins, frame connectors and roof base.
In short:
Purlins (logs or purlins) are placed on the splayed wood of the truss, fixed with grasshopper nails, or placed on the "beam" on the wall;
Wooden rafts are nailed to purlins at equal intervals according to tile width, which is convenient for covering yin tiles (ditch tiles). Above it is a small blue tile (cloth tile) roof. For machine tile (flat tile) roofs, the rafters are large tiles or thin paving roof panels.