Lumber

This report focuses on building code requirements for using fire retardant treated wood (FRTW) in floor/ceiling and roof/ceiling assemblies in Type III building construction. 

The BC beetle kill means changes are on the horizon for lumber harvesting, processing and pricing. 

Quality marks are not substitutes for grade marks—FRTW will include both!

Lumber Design Values

No matter the species, component manufacturers (CMs) purchase and rely on the accuracy and reliability of many different lumber design properties, including: bending (Fb); shear parallel to grain (Fv), compression perpendicular to grain (Fc^), compression parallel to grain (Fc), tension parallel to grain (Ft), and modulus of elasticity (E and Emin).

Quality marks are not substitutes for grade marks—PTW will include both!

Metal plate connected wood trusses are sometimes used in applications or environments that require the trusses to be designed and constructed with chemically treated lumber. The two most common types of chemically treated wood used in trusses are preservative treated wood (PTW) and fire retardant treated wood (FRTW).

This presentation provides an overview of fire-rated assemblies that include wood trusses. Topics covered include assembly testing, Harmathy’s rules, and an examination of fire performance in the field. 

Question: 

Is finger-jointed material allowed in the manufacturing of trusses?

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?

Question: 

Where can I find a copy of the criteria used to visually grade lumber?

Question: 

I market 2x4 and 2x6 structural finger-jointed lumber. As of now, we have strictly sold it as a #2 product. However, we ran some through a bender at a sawmill to test the modulus of elasticity and it looks promising. The equipment showed no recognition of the joint; it acted like regular lumber. We would like to go forward with this venture in the hopes of offering an alternative MSR to solid lumber that may also be more cost effective. What do you need to have from us to get your approval?