teejk
Veteran Member
- Joined
- Mar 3, 2012
- Messages
- 1,817
- Location
- Merrillan, WI
- Tractor
- JD 2020, IH CC 1250, Ariens 926 Snowthrower
teejk-
Totally disagree with you. I was in the business from 1976 to 2001. I ran a lumberyard and designed and sold hundreds of buildings- residential, agricultural, and light commercial. ALL trusses are specific as to the load ratings of top chord liveload (snow, wind) and dead load (roof framing and roofing materials), and bottom chord deadload (the weight of the trusses themselves and required bracing) and ceiling load (the weight of the ceiling framing, ceiling material, and insulation). Trusses ARE "designed on a project by project basis".They are produced in a factory, but they are NOT "mass produced", and NOT one size fits/does all! And also, NONE are "way over-engineered to handle drop weight" (whatever that is). The manufacturers have to keep costs to minimum to be competetive. Chords, truss plate types, and the webbing all vary in sizes and placement locations, depending on the loading and spacing specifications.
There are minumums for different applications- residential carries a minimum load rating for that use, whereas agricultural and non-inhabited buildings can be specified as to the load options as the buyer requests (within reason, but canl be below residential minumums). They can be ordered with either an agricultural or residential top chord loading, and can be ordered with a ceiling load or not. People don't have to order trusses that have a 15lb ceiling load to use on an outbuilding used for cold storage or livestock shelter. Wasted money if you don't need it.
His 2x4 nailers have a weight, fiberglass insulation has a weight, sheetrock DEFINATELY has SERIOUS weight. It all adds up.
The poster would be wise to consult a truss supplier to find out if these trusses were designed for that much weight. He may be in for a nasty surprise when he has to call his insurance agent when it snows heavily and the roof caves.
He may get by, and he may not, depends on mother nature. Of nothing else, forget the rolls of fiberglass and sheetrock/drywall (even the thinner stuff, which will sag in that application anyway). He could get by with 2x4 ceiling girts 4 to 6 feet apart, use steel liner panel for the ceiling, screwed to the girts, and blow fiberglass on top of that. It would be cheaper and lighter, and would require be easier to apply, as well as no maintenance. This is all contingent on whether the trusses will handle it. He's in a heavy snow load area, and those trusses may be maxed out for that area.
Not trying to be objectionable, just trying to help.
Sorry if I offended you...I perhaps oversimplified the truss process. what I meant to say was that "pole-barns" will have a standard truss taking into account width, over-hang, spacing, roof pitch and snow load. Since our multiple contractors around here know about snow load and generally do a 4/12 pitch and generally deal with an 18" or a 24" overhang, when it comes to truss construction they call it in and the truss plant builds them from existing plans (all engineered of course). In that respect they are truly a mass produced truss...I've ordered in the morning and they are available the next morning.
I got to see a truss plant in operation once...biggest layout table I have ever seen. But at the time I was amazed at how simple the process was once they knew the dimensions...as I recall it was mostly a radial arm saw cutting operation and the layout lines were marked on the table before the press set the gangnail plate. That was years ago and I'm sure CAD has a much bigger part to minimize waste.
Now I am speaking solely about the typical pole barn which is what we are talking about here. It sounds like the building is already in place. I'm sure the trusses were designed to handle "hanging weight" of 5/8" drywall (sorry I offended by saying "drop weight") but he can certainly verify with his truss maker.