Roof Trusses

Question: 

What is truss uplift?

Question: 

I almost always see wood trusses erected with no stability bracing at points of support. It seems to me that common sense and section 3.3.3.4 of The American Wood Council’s National Design Specification for Wood Construction (NDS) require that lateral support be provided at points of bearing. Plywood decking doesn't provide any more restraint for a wood truss than it does for a roof joist. I doubt if it was a concern with short span trusses having 4 in.

Question: 

The truss industry maintains that the design of truss roof and floor system permanent bracing is the responsibility of the building designer. System permanent bracing covers the entire structure and all bracing element interactions.

Question: 

What does KD-HT mean?

Question: 

Occasionally we deal with truss failures due to impact and or crushing forces such as trees falling onto roof structures. At what point can the truss no longer be repaired? Also, what should an adjuster look for when determining repair-ability? Or should a storm adjuster basically punt and call a consultant for every truss failure?

Question: 

What is the recommended way to frame gable end overhangs?

Question: 

If trusses blew down from insufficient temporary bracing and the contractor put them back up without the knowledge of the truss manufacturer and gave the truss manufacturer a letter stating that the trusses were okay, is that sufficient? Do you know of any truss manufacturer who would accept this?

Question: 

I am remodeling a 16-year-old ranch style home. The roof consists of 4/12 26 ft. span trusses, 24 in. O.C., over 2x4 stud walls. What is the recommended means of affixing the top plate of new interior partitions to provide the lateral support needed for the partition? Also, I want to hang a soffit above and overhanging the new kitchen cabinets (recessed lighting placed within). What is the recommended means of attaching the soffit to the underside of the trusses so as not to interfere with the designed movement of the trusses under the variable live load experienced (snow load)?

Question: 

What is the definition of an energy heel?

Question: 

As an engineer, I have noticed truss designers in some high wind states routinely using “Main Wind-Force Resisting Systems” wind pressure coefficients as opposed to “Components and Cladding” coefficients to design for wind uplift. A roof truss is not a main wind-force resisting system and would have to have a tributary area of more than 1000 sq. ft. before qualifying for the lower Primary Frame coefficients. In my experience this practice is routine.