Sheathing

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?

Duct And Light Penetrations Of Fire Rated Assemblies

Question: 

In a small scale multi-family residential project, I'd like to use a wood truss floor-ceiling assembly to achieve a one hour separation between units. I'd like to directly attach the drywall to the underside of the trusses & use the truss space for ducts & lighting (the floor above will be lightweight concrete on plywood sub-floor). UL assemblies do not seem to address the duct/light penetrations in such an assembly. Can I achieve a one-hour rating in such an assembly and how are penetrations addressed? Can the ducts in the truss space serve both units above and below?

Fire Rating For Truss Assemblies Built With 2x3 Lumber

Question: 

Are there any published studies or guidelines on the fire rating of floor trusses built with 2x3 lumber?

Old Fire Retardant Treated Lumber

Question: 

I have recently heard of a problem with fire-retardant-treated wood (FRTW) trusses that were manufactured and installed in 1965-1980. I was searching for more information, since my job involves the protection of property in our member school districts. I had heard that the trusses make of FRTW during that time period can or will become corrosive to the hardware and the trusses will fail.

Overdriven Nails in Structural Sheathings - Educational Program

This presentation provides information on overdriven nails in structural sheathing.

Overdriven Nails in Structural Sheathings

All building codes provide provisions for the attachment of structural sheathing to wall and roof framing members. In almost every case, the published capacity of the sheathing and fasteners assume the head of the fastener is flush with the surface of the sheathing. This Research Report discusses guidance when fasteners are overdriven.

Truss Repair - Educational Program

This presentation provides information on and requirements for truss repairs.

Installation of Interior Gypsum Board Finish

Gypsum wallboard provides an excellent example as to
why accurate design values are so vital to structural design.

Introduction: Why the Interior Finish Installation Is Important

Plywood vs. OSB Truss Repairs

  • Plywood and OSB design values are given; those that are doing repairs in your office should have a good feel for the similarities and differences.
  • Plywood and OSB generally have similar design properties with a key exception of fastener strength where plywood will require more fasteners to be used.
  • If a truss repair specifies only OSB, plywood should not be substituted without written permission from the registered design professional who prepared the truss repair design drawing.

Strength Axis in Wood Structural Panels

  • The strength axis of a structural panel is the direction parallel to the grain of the wood fiber in the face and back surfaces of the panel.
  • The strength axis is usually the long dimension of the panel.
  • The IBC provides two tables with the allowable spans and loads (psf) for wood structural panel sheathing installed continuous over two or more spans with their strength axis perpendicular and parallel to the supports.