Products

Uplift Values On Truss Design Drawings

Question: 

I am a building inspector and I have a question on information provided on truss design drawings. What does the uplift reaction number represent? Some manufacturers are very specific and state “to provide for mechanical connection of the truss to the top plate with a connector capable of withstanding a specific load.” Others simply list the uplift reaction with no further information. These are the ones that have caused a debate as to what the number actually represents.

Allowable Deflection In Floor Trusses

Question: 

Is there a chart available on the allowable amount of deflection on floor trusses?

Grade Marked Lumber

Question: 

When webs are cut is it alright that sometimes the grade mark is removed? From a liability standpoint, what is the rule with grade marks and web members?

Truss Uplift

Question: 

What is truss uplift?

Long Term Deflection

Question: 

Has there been any research or studies on long-term deflection of metal plate connected wood trusses? How much deflection is allowed?

Floor Vibration

Question: 

We have designed a custom home that needs a good solid floor, with low vibration perceptibility. The system we have specified consists of 2 in. of gypcrete over 1 and 1/8 in. thick plywood or OSB. The floor trusses are 20 in. deep at 16 in. O.C., spanning 31 ft. 6 in. The preliminary truss design shows a double top and bottom chord with a total load deflection of 1.30 in. (l/290) and a live load deflection of 0.65 in. (l/581). The basement ceiling will be 1/2 in. gypboard nailed to the bottom of the trusses.

Weights And Terminology Of Trusses

Question: 

How do I go about estimating the weight of a roof truss framing system? Is there a table of span vs. pitch vs. weight of trusses? Is there a guide available that shows how the components of various roof styles (hip, gable, etc.) are commonly framed and the associated terminology?

Partition Separation Lag Bolting

Question: 

Is lag bolting the bottom chord of a truss to the top plate of a wall a proper fix to correct truss arching, assuming the attic is properly vented?

Age Restriction On Lumber In Trusses

Question: 

I would like to know if there is an age restriction on wood trusses. How long after production are they safe to use? The trusses in question are at least three to four months old. Are they still safe to use? They have not been covered the entire time and are showing signs of age.

Use Of Metal Plate Connected Wood Trusses In IBC Jurisdictions

Question: 

IBC 2012/2015 2303.4.6 and IBC 2012/2015 2303.4.7 state: 
2303.4.6 TPI 1 specifications. In addition to Sections 2303.4.1 through 2303.4.5, the design, manufacture and quality assurance of metal-plate-connected wood trusses shall be in accordance with TPI 1. Job-site inspections shall be in compliance with Section 110.4, as applicable.