Sheathing

Charring Of Trusses

Question: 

Our home caught fire last month and burned partly through a tongue and groove ceiling to the trusses. Some are charred. Our contractor did a moisture meter test. An engineer for the insurance company said the trusses were only smoke damaged & the moisture meter test is invalid (it can be set to read anything). I found one article on charred trusses, but it’s pretty vague. We do not feel safe with the insurance engineer’s assessment because some of the trusses are obviously charred. We hired an engineer who agreed with us.

Spacing Requirements On Sheathing

Question: 

I am looking for help on the spacing required to screw down a BHP B-36 20 gage roof deck to wooden trusses spaced at 5 ft. 4 in. O.C. and 24 in. O.C. Do you know of any published codes or specifications on the above?

Adding Tile To Existing Floor Trusses

Question: 

We are planning to add 1/2 in. cement board and 3/8 in. quarry tile to a kitchen floor. We need to know if the floor trusses will handle the additional weight. The floor trusses are 19.2 in. O.C. and the loading numbers are 40-10-0-5. What do these numbers mean?

Substituting Fire Rated Wood Truss Assemblies For Light Gauge Steel

Question: 

We recently received bids on a school project, which referenced UL P523. This assembly used light-gauge steel trusses. We noted on the drawing that we could accept an alternate design using wood trusses in lieu of light-gauge steel framing, if the alternate design could meet the fire ratings.

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.