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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.
I am researching building products for a new home and I wanted to use metal plate connected floor trusses. When I took my plans to the builder, they cautioned me against using these floor trusses. They stated that they were not engineered products, they do not carry any kind of warranty, and they do not know how long they last over time. My basement span is 30 ft., they said trusses could not span 30 ft. I really would like to use floor trusses, but now I am unsure. Could you offer any information?
We keep having problems with dry wall joints raising on the vaulted bottom chords in the track homes that we are building. The joints run from front to back of the house and the trusses bear on the side walls. The trusses are mostly 2-point bearing (a few in the front and back of the building are tri-bearing). The trusses span 40 ft. and have a 4/12 pitch with a tile roof. Is it common to have dry wall problems as the trusses deflect? How long should the roof be loaded before hanging sheetrock? Should the heel of the truss be allowed to slide out on the top plate?
Is lag bolting the bottom chord of a truss to the top plate of a wall a proper fix to correct truss arching, assuming the attic is properly vented?
I want to get a good definition on what causes “truss lift,” when the trusses will actually raise off the top plates of interior walls (even when nailed), causing the drywall to crack. Is it from drastically different temperatures in the attic and living area?
I installed roof trusses in my house and dry walled the ceiling to the bottom of the trusses. Now I seem to have a problem with the change of the seasons. Where the ceiling meets the interior wall, a gap opens and closes – in winter it opens, in summer it closes. What did I do wrong, how can I correct it and how should the drywall be installed in the first place?
I'm looking for a book that will provide formulas and design criteria for trusses. Can you give me any suggestions of where to find a book or fairly inexpensive software?
I am building a new shop that is 30 ft. x 32 ft. I need to free-span the 30 ft. dimension. Where can I get a load chart that recommends lumber size and strategic locations of the angle braces to support the free span? I am going to field erect the trusses and stick build them on the building.
I am planning a 36 ft. x 60 ft. clear-span horse barn with posts set 12 ft. O.C. If I use 2x6 verses 2x4 wood trusses what would the proper spacing be? The roofing is 29 ga. K-panels metal with insulation, and winter snowfall is minimal in our area.
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.
We are building a garage with a bedroom and bathroom and trying to find out what type of floor joists and roof trusses to use. The garage will be a 26 ft. by 32 ft. with a 26 ft. by 32 ft. room upstairs. But we don't want to have posts in the middle of the garage to help support the weight of the second floor.
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.
The lumber used in most metal plate connected wood trusses is either visually- or mechanically-graded solid sawn dimensional lumber. However, the Truss Plate Institute's ANSI/TPI 1 allows the use of structural composite lumber (SCL) products such as laminated veneer lumber (LVL), laminated strand lumber (LSL) and parallel strand lumber (PSL). These engineered wood products can conceivably compete with sawn lumber and complement it in truss designs.
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.
I am a building designer on a salt storage building project. I would like to use metal plate connected wood trusses in the design. What should I specify for the metal connector plates?
Has there been any research or studies on long-term deflection of metal plate connected wood trusses? How much deflection is allowed?
We have designed a custom home that needs a good solid floor, with low vibration perceptibility. The system we have specified consists of 2 in. of gypcrete over 1 and 1/8 in. thick plywood or OSB. The floor trusses are 20 in. deep at 16 in. O.C., spanning 31 ft. 6 in. The preliminary truss design shows a double top and bottom chord with a total load deflection of 1.30 in. (l/290) and a live load deflection of 0.65 in. (l/581). The basement ceiling will be 1/2 in. gypboard nailed to the bottom of the trusses.
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?
Is there a chart available on the allowable amount of deflection on floor trusses?
Are there charts illustrating allowable HVAC duct sizes that can fit between truss chords for various truss depths?
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.
What is the recommended standard spacing for open-web wood joists? I have seen them placed 24 in. O.C. Is this acceptable for a customer who will have an exercise room with 500 pounds of free weights? I understand there are problems with bouncy floors with 24 in. spacing. Is this true?
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?
Are there any typical wood truss span tables for roofs and floors available? Standard framing details for use in preliminary design?
Where can I find specs for what would be adequate trusses? I have a room with a 24 ft. span and my contractor is using trusses where the bottom plate is composed of 2x4s butted together and fastened with a metal plate. Is this ok?
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?
I am a structural engineer on a project with a wood trussed roof. I have noticed some variations in the peak height in a run of identical trusses. Do you have any information on tolerances for the final dimensions of manufactured trusses?
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?
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?