Moisture Control

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?

Proper Storage And Shipping Of Trusses

Question: 

I would like to know the proper storage and shipping of wood trusses.

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?

Lumber Concerns In High Temperature Low Humidity Climates

Question: 

I have been told that the high temperatures and low humidity present in attics can cause deterioration of wood, leading to truss failure. Is this true? If so, what length of time are we looking at and can we see the deterioration in the wood by visual inspection?

Gypsum Joint Ridging and Cracking

Drywall cracking and ridging are typical problems seen in ceilings and walls of homes. Sometimes, both of these issues appear at the same location, with cracking appearing in wetter months and ridging in drier months. This problem has become more widespread as homeowners insist on larger rooms and open floor plans that have large clear span areas. This Research Report evaluates local environment changes that play a significant role in every gypsum ridging and cracking case.

Designing for Damp Conditions

A truss designer who recognizes conditions that require a reduction in lumber or plate design properties can help ensure trusses perform as the building designer intends.

Using Trusses in Corrosive Environments

  • Standard metal connector plates are suitable for use in lumber with moisture content of 19 percent or less and in building applications with no exposure to corrosive substances.
  • Connector plates used in trusses exposed to high humidity or caustic chemicals may need to be treated to prevent corrosion.
  • A variety of protective coatings can be applied to truss places in situations where special protection is necessary.