Roof Trusses

Fire Cuts

Question: 

What type of construction uses a fire cut truss? Could you describe a fire cut truss?

Trusses In Corrosive Environments

Question: 

I am a building designer on a salt storage building project. I would like to use metal plate connected wood trusses in the design. What should I specify for the metal connector plates?

Lumber Grades In Wood Trusses

Question: 

The grading rules usually permit some percentage of visually graded lumber to be below grade – I believe it is 5%. ANSI/TPI 1 requires that all lumber used in trusses be of the grade specified by the truss design. A strict interpretation of ANSI/TPI 1 would require that the fabricator cull the 5% that is off grade. What are your thoughts on this?

Design Loads Vs Typical Loading Conditions

Question: 

The Corps' guide spec for wood construction requires the drawings to indicate the design forces on each truss member for the worst loading condition. Loading conditions, of course, can include wind, snow build up, and unbalanced loading, to name a few. Many A/E firms submit drawings lacking these member forces, but instead show typical loading conditions. What does the wood truss fabricator want to see – truss diagrams with maximum loads on each member? Or would he prefer to design the truss from many required loading diagrams?

Jack Truss Connections To Girder

Question: 

In a hip roof application where jack trusses connect to a girder truss using pressure blocking (power blocking), what is the proper installation and the span that is acceptable before a hanger is required?

Snow Load

Question: 

I am a truss manufacturer in an area of the country that often has some pretty severe winters. It concerns me how little some of the local builders seem to know about snow load design. What are some of the things that need to be considered?

Gable End Bracing

Question: 

Is there a detailed table for gable studs that gives the maximum length a vertical member can be before a lateral brace is required?

Truss History

Question: 

How long has the truss industry been around and where did it start?

Decking On Bottom Chord

Question: 

Can I put a wood deck (1/2 in. plywood) on top of the bottom chord of a 26 foot span truss 24 inches on center?

Location Of The Metal Connector Plates

Question: 

I was working on a job that had trusses that span more than 78 ft. with a 9/12 pitch. We had the #5 truss being installed when the #4 truss gave way. The trusses that were being installed are a two part system. The bottom set is what you would call hip trusses. The trusses contained 2x6 bottom chords, 2x8 top chords and rafters, and 2x4 webs. The roof sheathing was to be 3/4 in. plywood, 15 lb. felt paper and roof shingles. The ceiling was to be 5/8 in. drywall. The #4 truss sheared about 1 in. off the wall.