Performance

Floor Truss Span Tables

Question: 

Do you have open web floor truss span tables available?

Repairs To Field Modified Damaged Trusses

Question: 

As a home inspector, I have recently inspected an existing home with an attic truss system installed. Several of the truss web members have been cut away to allow access to an attic-mounted heating system. Can you recommend repairs to a truss with cut web members?

Penetration Of Fire Walls

Question: 

Can a roof truss penetrate a one-hr. tenant separation wall without having a one-hr. rated ceiling? The building official insists that the 2x4 chords are combustible and nullify the integrity of the one-hr. rated partition that is constructed in an attic above an 8 in. C.M.U. bearing wall. The partition consists of gypsum board attached to 2 x 4 stud framing. The building official insists that a ledger must be attached through the gypsum board to support the trusses each side of the wall. This is almost saying that any rated assembly must have bearing only on other rated assemblies.

Gable End Bracing

Question: 

Manufactured gable ends are actually frames even though they are often referred to as trusses. The webs are “studs” oriented vertically and usually spaced at 12, 16 or 24 in. O.C. The gable end frame is designed to transfer vertical loads from the roof to the continuous bearing wall below. Another way gable end frames are different from trusses placed in the interior of the structure is that frames experience perpendicular wind loads. The sheathed frame transfers the wind loads to the roof and ceiling diaphragms and vice versa.

Continuous Lateral Bracing

Question: 

How important is continuous lateral bracing in roof trusses? Is it detrimental to the roof integrity if it is missing?

Floor Trusses With Masonry Bearing Walls

Question: 

We would like to know if there is a problem with using wood floor trusses with masonry bearing walls without a ledger. Our local supplier has told me that encasing the wood truss in the masonry wall could be detrimental to the truss due to moisture. What, if any, suggestions do you have for this condition? If a bottom chord bearing is used, do the trusses need fire cuts? The two-story building contains masonry bearing walls with wood trusses on the second floor and wood trusses at the roof.

Attic Ventilation

Question: 

I need to put a new roof on my single-family dwelling. The house originally had gable and soffit/eave vents. The roofing contractor suggested that we install a ridge vent when new roof is installed. Should the existing gable vents be blocked off or does it not matter? I have read some debates about whether or not the combination of gable and ridge vents substantially reduces the effect of the soffit vents by having the intake now at the gable vents and exhaust at the ridge. Would this type of ventilation affect the truss warranty?

Health Hazards Of Mold On Lumber

Question: 

What are the health hazards of black fungus on Douglas-Fir lumber?

Life Expectancy Of Wood

Question: 

What is the life expectancy of wood that was used in an attic truss? Does fire retardant change the life expectancy?

Lumber Fatigue And Decay

Question: 

What is fatigue in lumber and how does long-term fatigue affect lumber? Does long-term fatigue cause cracks in lumber? What is the difference between long-term fatigue and decay? How do you determine whether lumber has been subject to long-term fatigue or decay?