Strong Backs And Purlin Braces For Large Open Attic Space

Purlin systems are designed to reduce the distance that rafters have to span.

Strong backs and purlin braces for large open attic space.

I just finished a roof structure yesterday using 2x8 rafters 16 oc spanning 17 6 over 2x8 joists 16 oc purlin required one nominal size over the rafter on struts same as rafter size. Shall be supported by 2 x4 braces installed to bearing walls at a slope not less than 45 degrees from horizontal. On a 4 12 pitch ranch house. Braces spaced not more than 4 feet on center.

September 12 2020. Purlins shall be no smaller than the size of the rafters they support. One kind is used if you are going to finish the attic to provide living space. They consist of strongbacks nailed to the undersides of the rafters and supported by diagonal braces.

So a question on purlin braces for you. Purlins as shown in sample photos below are installed for rafter support. In this situation the walls of a finished attic space or room would go with the roof line. Truss clusters for maximum strength this image shows a cluster of three trusses tied together.

Purlins 24 oc are typical along with the bottom bracing shown. Also sometimes known as a strong back a strongback is a type of construction that helps to enhance the strength of some type of structure by adding a secondary support at a key point in the design the idea is to provide additional support at points in which the failure of the main support network would lead to the collapse of the. In addition two types of braces can be used in an attic to provide extra support for the trusses if needed. The other is just used to support the trusses.

Full width shear on attic wall to shear walls running 42 width of building with all the required hardware and transfer. Purlins shall be continuous. Malcolm tatum last modified date. Homeowners cannot take chances with the structural integrity of their roofs.

To strengthen the roof system truss clustering cross bracing and wind bracing is recommended at both end of the buildings and every 20 for longer span buildings. The braces struts or kickers should be within every 4 and should not be at a greater than a 45 degree angle towards the roof slope lower side. Unbraced length length of braces shall not exceed 8 ft. The length of the purlin brace cannot exceed 8 feet without being braced.

How to brace rafters in an attic. Purlins braces shall be 2 x 4 s and shall be installed to bearing walls.