Moisture Control

The following checklists are to be used as a practical guide in conjunction with the information on mold provided in SBCA Research Report 1807-01: “Mold on Structural Building Components.”

This research report seeks to provides fact-based information about causes, effects, and mitigation of mold growth on lumber and wood structural building components. 

Mold on Wood Structural Building Components

Issues involving mold on building materials, whether during construction or in completed and occupied structures, have gained media attention in recent years. Unfortunately, the emotion, with respect to both real (e.g. asthma) and perceived health effects of mold-related situations, leads to actions that may not be grounded in sound science. This webinar will provide fact-based information about causes, effects, and prevention of mold growth on lumber and wood structural building components. 

Continuous insulation (ci) and cavity insulation products are both sold with R-value ratings, but the way these two products are used in wall construction means they do not have the same effectiveness.

We are having a house built and on a recent visit we brought along a friend who builds houses for a living. He noticed that the trusses were wet and a bit moldy. The wood seemed warped, brown, and had white splotches on it. We are worried that it would later make the roof uneven. How could we tell how long the trusses have been exposed to the elements? What options do we have from here? Do we request new trusses, or can these be repaired?

Some questions have been raised regarding the levels of mold in the lumber used in one of our truss projects. The issue of indoor air quality is up and coming. Do you have any information regarding standard allowable values? And how can we test for these contaminants?

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

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.

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.

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.