Market Education

Best Practices Provide a Best-Case Scenario

SBCA’s library of technical design and installation best practices has been expanded over the past year to help CMs navigate a wide array of code-related challenges in their markets.

The Right Tools in the Toolbox

Sometimes it’s hard to start a conversation. You know what you want to say, you think you know how the person you’re talking to will react, and yet finding the words to get the ball rolling and respond to the questions you know you’ll get is tough.

Multi Ply Girders

Question: 

Girders are trusses specially designed to carry extra loads that are a result of the structural framing members they support. Sometimes a single ply girder truss is insufficient to carry the entire load, so the truss designer designs a multiple-ply girder. This is where identical trusses are built and fastened together to act as one unit to support the load. ANSI/TPI 1 states that girder trusses up to three plies thick can be fastened together with nails. Girders over three plies must be pre-drilled and bolted rather than nailed.

Industry Standards

Question: 

I am currently putting together a set of truss specifications for a set of structural plans. I am interested to know of the most current publication that may specify industry standards in truss components (i.e. metal connector plates, wood quality and connection quality). Do you have any suggestions?

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.

Ubc Truss Marking Provision

Question: 

I stamp the bottom chord of my trusses with my company name and the name of my third-party inspector. Recently, my local building inspector requested another stamp with the on-center spacing, the total design load and the load duration factor. I have never heard of this before and I was wondering if you had any further information on this requirement.

Long Term Deflection

Question: 

Has there been any research or studies on long-term deflection of metal plate connected wood trusses? How much deflection is allowed?

Weights And Terminology Of Trusses

Question: 

How do I go about estimating the weight of a roof truss framing system? Is there a table of span vs. pitch vs. weight of trusses? Is there a guide available that shows how the components of various roof styles (hip, gable, etc.) are commonly framed and the associated terminology?

Retrofitted Shed Dormer

Question: 

I own and live in the middle unit of a one-story tri-plex that has a truss-framed roof. The interior has high ceilings that would potentially allow the addition of a second floor room. I am contemplating adding a shed dormer to create a second story bedroom. Do you have any suggestions as to how a shed dormer could be added? I am familiar with how to frame up a shed dormer if the original framing were rafters and a ridge board, but the truss construction has thrown me for a loop.

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.