Materials

A Designer’s Guide to FRTW

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).

A Designer’s Guide to PTW

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).

Fire Assemblies: Performance and Application Using Wood Trusses - Educational Program

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. 

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?

One Hour Roof Ceiling Assembly

Question: 

I am looking for a 1-hour roof/ceiling assembly for wood truss construction. I would like to apply the drywall directly to the bottom of the truss and also have insulation for sound control. Is this possible without using channels and what UL number would I use?

Visual Grading Criteria

Question: 

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

Two Hour Assembly Ul Number

Question: 

We have a local builder wishing to use floor trusses with a 2-hour assembly. I have shown him the 2-hour design on pages 17-27 of the second edition of SBCA’s Metal Plate Connected Wood Truss Handbook. Is this assembly UL approved? If so, what is the design number?

Health Hazards Of Mold On Lumber

Question: 

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

Metal Connector Plates In Fires

Question: 

I am thinking of using wood trusses for the roofing/ceiling structural systems on some houses I shall build. I remember, though, an engineer/volunteer fireman commenting back in 1989 that the connector plates are prone to expand and pop off, early on in a fire, causing catastrophic structural failure. Was this the case, and if so, has this problem been corrected?