Products

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.

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.

Alternate Nailing Patterns

Question: 

Some truss lumber repair nailing patterns call for 16d common nails. Most nail guns do not support 16d nails, but have an equivalent to a 12/10d nail. Is there a substitution guide or ESR report that could help us?

Impact Sound Transmission Through Floor Assembly

Question: 

A condominium project I am involved with is experiencing a sound transfer problem through the floor/ceiling assembly between the first and second floor. You can hear every footstep, from an adult to a child. The floor assembly consists of a carpet and pad, 3/4 in. OSB sub-flooring, 15 in. deep wood trusses at 16 in. on center, 9 in. fiberglass batt insulation and a 5/8 in. gypsum board ceiling. The trusses span 20 ft. with air/heat ducts between the trusses. Will an additional layer of 5/8 in. gypsum board attached to 7/8 in.

Truss Technician Requirements Definition

Question: 

What are the qualifications (if any) required to be considered a truss technician?

Truss Design

Question: 

Recently, I was invited to view a newly-constructed 60 ft. by 36 ft. barn, with homemade big timber trusses as follows: 36 ft. span, 12/9 pitch, construction was 26 ft. 2x12 rafters, bracing 2x6, ceiling joists were 36 ft. boxed, 6x12 out of overlapping (6 ft.), 2x12 glued and nailed center, 16 feet of joist doubled as an 8 ft. high loft, floor trusses were on 12 ft. centers atop posts deeply anchored with good footings, roof and wall cross ties were 2x6 on edge every 24 in., floor cross ties in the loft were 2x8 on edge every 16 in., 4 ft. snow load.

Sprinklers Above Gypboard Ceiling

Question: 

I have a 29 x 72 mobile office with a 2-foot deep wooden truss above the ceiling that a client is required to sprinkler. Is there any way to avoid sprinklering above the gypboard ceiling?

Unsecured Spacers

Question: 

During a home inspection, the inspector stated that the spacers were not secured at the attic trusses. What did the home inspector mean by this?

Installation Guidelines

Question: 

What are the requirements on the permanent bracing of bottom chords? Can gypsum board diaphragms be used?

Attachment Of Scissors Trusses

Question: 

What is the correct method of attaching scissors trusses to the top plate? I read recently in a trade magazine that this type of truss should be toe-nailed on one end and attached with slotted clips on the other end. According to the article, this is to allow for movement of the truss. We require PE stamped spec sheets from the truss manufacturer to verify trusses meet wind and snow loads. These sheets give bracing requirements but never give recommended attachment requirements.