Moisture Control

Mold On Lumber

Question: 

I am looking for some information regarding black surface mold on lumber. Does it alter the integrity of the lumber stress values? I have a client who wants to use “all dry” lumber for his construction but I do not know if this is really necessary.

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.

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?

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.

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.