Purlin Roof Framing Diagram

This view is from the inside of the building below the roof.

Purlin roof framing diagram.

Where the tie beam joins the wall framing we have the tying joint. In wide structures rafters are often supported by purlin. The fascia board is the bottom plate and the ridge board the top plate. The roof truss structure and design is integral to roof structural integrity and shape.

If the unit of rise in inches is 3 then the cut is the unit of rise and the unit of run 12 inches or 3 12. When a tie beam joins the feet of principal rafters the result is a triangle a rigid struc tural shape. Stick to the basics of simplified design and use dimensions that don t generate waste. 1 8 pitch is given so 24 x 1 8 equals 3 or unit of rise in inches.

The purlin are ultimately used to fasten the roof steel providing a diaphragm effect along with the siding when properly engineered and installed. Tying joints are usually the only connections in a frame that must resist tension. Purlins are dimensional lumber that are fastened to the top chord of trusses connecting them together for bracing purposes. There are many types of roof trusses as wall as many types of roofs more types than there are parts.

Keep it simple and remember. Outward thrust of the roof planes. Also referred to as secondary structurals this type of framing runs in between primary framing elements creating a structure within a structure much like cross beams in a wooden building. A view of a roof using common purlin framing.

Component w sinθ in the plane of the sheathing. This article and series of illustrated diagrams shows you all the parts of a basic roof truss king truss and queen truss. In architecture or structural engineering or building a purlin or purline is a horizontal structural member in a roof. About the base of the purlin based on the free body diagram shown in figure 3.

The rafters are the beams of wood angled upward from the ground. Line length is the hyptenuse of the triangle whose. Secondary framing is an important component of many pre engineered metal buildings. Framing a shed roof is similar to framing a wall.

Figure 2 2 roof framing terms. They meet at the top of the gable at a ridge beam which has extra bracing to attach it to the rafters. For a sloped roof the components of the gravity load are divided into a normal.