Frequently Asked Technical Questions

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Frequently Asked Question

It is critical that permanent top chord bracing is supplied by proper nailing of the valley truss bottom chords to the carrying truss top chords, through purlins or properly installed rated roof sheathing. If the sheathing is not carried through under the valley framing, then the permanent top chord bracing must be supplied in another manner.

Frequently Asked Question

I would like to know the proper storage and shipping of wood trusses.

Frequently Asked Question

Do you have information on purlin grades and species to meet 50 psf top chord live load using 2x4s on edge 24 in. O.C. over trusses at 6 ft. O.C.?

Frequently Asked Question

How high is a high heel?

Frequently Asked Question

We are experiencing problems with bouncy wood floor trusses. I'm wondering what the industry standard is on deflections (live and total load). Also, do you have any ideas on how to decrease the deflection without affecting the profit margin significantly?

Frequently Asked 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.

Frequently Asked Question

As a home inspector, I have recently inspected an existing home with an attic truss system installed. Several of the truss web members have been cut away to allow access to an attic-mounted heating system. Can you recommend repairs to a truss with cut web members?

Frequently Asked Question

When you’re selling trusses through a lumberyard and the contractor calls to say that the “trusses don't fit correctly,” who has the ultimate responsibility for the trusses? I argue that the lumberyard is responsible since we have provided them with all the information on how the job was designed, even though they may or may not have passed this information on to the contractor.

Frequently Asked Question

I am reviewing a truss package that includes multi-ply trusses. Where do I find the requirements for the attachment of the individual trusses to each other (nails and/or bolts)? Is this a requirement that the structural engineer of record needs to supply or is it the responsibility of the truss manufacturer to design?

Frequently Asked Question

Is the truss designer or the building designer responsible for calculating snow drift loads on a roof system?

Frequently Asked 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.

Frequently Asked Question

If you use hurricane clips to secure roof trusses from uplift, are you allowed to use fewer than the typical three nails in the bearing heel of the roof truss? I am concerned because we want to do the right fastening schedule, but three nails in addition to the hurricane clip splits the wood. What is the standard recommendation?

Frequently Asked Question

I am investigating a roof failure in a 22-year-old structure. The connector plates have peeled open like a banana skin in several instances. The teeth do not appear sheared or torn at the wood surface. However, the plates will be in firm to one member and separated in the other (a gap of about 1/32 in.). Although there are large deformations, the roof is still standing. There was a heavy snow before the problem became apparent. Do you have any insights?

Frequently Asked Question

Can I safely install 3/4 in. T&G, OSB on 2x4 trusses that are 24 in. O.C.? My roof was installed over 5/8 in. plywood without clips that have caused a lot of sagging and the shingles need replacing. I want to “fix” it one time and install architecture type shingles, but the garage is 24 ft. wide and 28 ft. long without any load bearing walls. My concern is the weight on the trusses. 5/8 in. plywood weighs 52 lbs. and the OSB weighs 78 lbs. for each 4 ft. x 8 ft. sheet. The roof will require about 84 4 ft. x 8 ft. sheets to cover, which equals about 2,184 lbs.

Frequently Asked Question

We are finding it difficult to design permanent diagonal bracing for scissors trusses. The truss is often only a few feet in depth, which does not provide adequate room for diagonal bracing. Has SBCA come up with recommendations for permanent bracing of scissors trusses?

Frequently Asked Question

Is it the responsibility of the truss manufacturer to provide a sealed layout drawing for roof trusses?

Frequently Asked Question

If you have the condition where you are out by the max tolerances of 1/2 in., how do you correct the situation? Do you shim the truss from the bottom? Shim from the top? I will assume you do not shave the truss off. What is the published corrective action for situations that cannot handle the variation in truss height?

Frequently Asked 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.

Frequently Asked Question

In our one-year-old home, as you approach the hallway, the floor slopes downward. Our home inspector said that this was most likely due to the fact that the walls were resting on the floor as opposed to being load-bearing walls. What has been your experience with sloping floors in a new home? The floors are very flat elsewhere until the walls start. Do you think this sloping could turn into a structural problem eventually?

Frequently Asked Question

I am a truss manufacturer in an area of the country that often has some pretty severe winters. It concerns me how little some of the local builders seem to know about snow load design. What are some of the things that need to be considered?