Product Performance

Post Fire Retardant Treatment

Question: 

Is a Class A fire rating (provided by our liquid spray-on fire retardant) acceptable in certain situations?

Fall Protection

Question: 

Are wood trusses designed to be fall protection anchors that would support a worker should he fall?

Truss Design Factors Of Safety

Question: 

I am currently working on a project where a wood truss system was loaded with a heavy spring snow. I do not believe the load was beyond the truss's design capacity, but how do you know? Is there safety built into wood trusses? If the trusses were loaded beyond their design capacity, it would not have been for a long duration.

Truss Bracing At Supports

Question: 

I almost always see wood trusses erected with no stability bracing at points of support. It seems to me that common sense and section 3.3.3.4 of The American Wood Council’s National Design Specification for Wood Construction (NDS) require that lateral support be provided at points of bearing. Plywood decking doesn't provide any more restraint for a wood truss than it does for a roof joist. I doubt if it was a concern with short span trusses having 4 in.

Testing Wood Truss Strength

Question: 

We are building churches in Europe. These are modified pole barns and we are trying to use local materials and local volunteer labor. Since the truss is the heart of the building, I am looking for a method to test some completed trusses before the building is started to make sure they are strong enough.

Size Of A Room In An Attic Truss

Question: 

Does SBCA have any guidelines regarding the size of a room in an attic truss? I have used a formula, length of room in inches divided by the depth of the bottom chord equaling less than 22. I was curious if any extensive studies or published articles giving more exact guidelines are available.

Repairing Incorrect Floor Truss Installation

Question: 

I have a four-year-old house with glued open-web trusses. Both the truss manufacturer and the builder have admitted to me that the trusses were installed wrong. I have a problem with the suggested repair. I have hired a structural engineer and he suggested installing a 2x10 between each truss and removing the old truss. This would have to take place on both the first and second floors because all the trusses were installed wrong. The manufacturers want to install six strongbacks on each floor, hoping this will tighten them up.

Sound Rating Information

Question: 

Do you have sound rating information for floor truss assemblies (i.e., STC and IIC ratings)? We are looking specifically for ratings for 12 in. floor trusses, with 1 and 1/2 in. concrete topping and without the topping. We are looking to meet the minimum code rating of STC 45 and IIC 45.

Gable End Bracing

Question: 

Some building designers believe that gable end webs need to be L-braced to 90% of the web length, which sounds fine. However, they spec that scissors gable end webs need to be braced to 100% of the web length. That means that in the field they are notching the braces to fit around top and bottom chords – you can imagine how difficult that can be. Is that necessary or even the intent of the web L-bracing?

Ga Rc 2601

Question: 

In RC 2601, is RC-1 Channel used?