Strongback Roof Framing

I d be expecting the joists to frame into the beam.

Strongback roof framing.

Strongback header minimizes number of members to be installed vs. Truss two runs for longer trusses. It serves to make the floor more comfortable for those living and working in a structure. There was no sagging so there was no comment in the inspection report.

Purlin systems have been built in many ways some better than others. But the rafters must resist bending flexion where they are relatively weaker. Modern building codes call for strongbacks to be of equal or greater. Back to back or boxed header.

With no central wall to carry the braces they bear on a strongback that rests on the ceiling joists. The cross tie exerts its strength in tension so it can be made of smaller size lumber such as a two by four. 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 structure as a whole. For more information on bracing parallel chord trusses see sbca s bcsi b7 summary sheet.

A typical peaked roof frame consists of two rafters with a cross tie to keep the tops of the walls from spreading. Underneath 2x6 strongbacks laid on edge should run continuously through the webs of all the trusses at 10 ft. The 2x6 serves the same purpose as bridging in a standard floor distributing concentrated loads over a wider area. The first approach to achieving a strong durable struc ture involving economical use of materials is to follow a basic modular plan for layout and attachment of framing members.

A strongback is a replacement for sheathing. The strongbacks should be restrained to solid framing whenever possible. Using a wider flange and thicker jamb stud material reduces cost of installation compared to built up jamb studs. Strongback infill stud advantages.

Strongbacks can be altered to allow hvac installations as long as three 3 consecutive joists are attached. Such methods use a 4 foot design module which governs a 16 inch spacing of joists studs rafters and panel sheathing products. Use of cripple stud to receive head sill tracks at the jamb studs helps maintain alignment of finishes. In my opinion the weight of the beam would actually make things worse.

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. Strongback bridging is an excellent and inexpensive way to improve the overall rigidity of the floor system and eliminate vibration.