Purlin Roof Framing Diagram

Tying joints are usually the only connections in a frame that must resist tension.

Purlin roof framing diagram.

Stick to the basics of simplified design and use dimensions that don t generate waste. In wide structures rafters are often supported by purlin. In architecture or structural engineering or building a purlin or purline is a horizontal structural member in a roof. Where the tie beam joins the wall framing we have the tying joint.

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. Line length is the hyptenuse of the triangle whose. 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.

1 8 pitch is given so 24 x 1 8 equals 3 or unit of rise in inches. Component w cosθ perpendicular to the plane of the sheathing and a downslope. A view of a roof using common purlin framing. Framing a shed roof is similar to framing a wall.

The rafters are the beams of wood angled upward from the ground. Purlins are dimensional lumber that are fastened to the top chord of trusses connecting them together for bracing purposes. About the base of the purlin based on the free body diagram shown in figure 3. Purlins support the loads from the roof deck or sheathing and are supported by the principal rafters and or the building walls steel beams etc.

When a tie beam joins the feet of principal rafters the result is a triangle a rigid struc tural shape. Secondary framing is an important component of many pre engineered metal buildings. This article and series of illustrated diagrams shows you all the parts of a basic roof truss king truss and queen truss. The roof truss structure and design is integral to roof structural integrity and shape.

Shed roof framing process explained step by step instructions. The fascia board is the bottom plate and the ridge board the top plate. Keep it simple and remember. They meet at the top of the gable at a ridge beam which has extra bracing to attach it to the rafters.

Figure 2 2 roof framing terms. There are many types of roof trusses as wall as many types of roofs more types than there are parts. Component w sinθ in the plane of the sheathing.