Will the Ceiling Collapse?

[bhh]

I am an architect and without actually inspecting the structure, I think you are completely fine to hang 1/2" drywall. Anything less than 1/2" will sag though. The additional weight each truss will carry is equal to 270 SF of ceiling (30' x 9'). At around 2lb per SF for 1/2" drywall, that is 540 lbs of drywall. 2x4s run around 1.25 lbs per linear foot so at 9', you are talking about 11.25lbs each. 30' is 360" divided by 16" spacing = 22.5 so you will have 24 2x4s times 11.25lbs each equals another 270 pound of wood. That is 810 pounds of additional load per truss or 3lb per SF. Not sure exactly where you are at but your roof is probably designed for at least 30lbs per SF of live load (wind and snow) and most likely at least 10lbs of dead load so I think you are well within a reasonable comfort zone. I probably wouldn't store much up there and be careful that your walls bear properly on the floor rather than "hanging" from the ceiling or trusses.

 

[teejk]

I am an architect and without actually inspecting the structure, I think you are completely fine to hang 1/2" drywall. Anything less than 1/2" will sag though. The additional weight each truss will carry is equal to 270 SF of ceiling (30' x 9'). At around 2lb per SF for 1/2" drywall, that is 540 lbs of drywall. 2x4s run around 1.25 lbs per linear foot so at 9', you are talking about 11.25lbs each. 30' is 360" divided by 16" spacing = 22.5 so you will have 24 2x4s times 11.25lbs each equals another 270 pound of wood. That is 810 pounds of additional load per truss or 3lb per SF. Not sure exactly where you are at but your roof is probably designed for at least 30lbs per SF of live load (wind and snow) and most likely at least 10lbs of dead load so I think you are well within a reasonable comfort zone. I probably wouldn't store much up there and be careful that your walls bear properly on the floor rather than "hanging" from the ceiling or trusses.

Unless you order "attic" trusses, my understanding is NO load above. Standard pole barn scissor trusses would make it hard to do anyway. That steel option escaped me (even though that's what I have in my shop...a DUH moment). I haven't priced it lately but I think it might be comparable to drywall. And it looks nice...no taping, no sagging, quick install and LIGHT.

 

[bhh]

I am admittedly ignorant on pole barns specifically but basic engineering and building codes still apply. My guess is that "attic" trusses are probably engineered for 20 lb per SF of dead load. 3 lb per SF is equivalent to about 2.5-3" of snow if that helps put things in perspective. I should probably add the typical disclaimer that you and you alone assume the risk of anything you do yourself without hiring a professional. :2cents:

 

[Gary Fowler]

You are most likely correct about the truss design on standard pole barn size structures...but I guarantee anyone that sells said trusses has copies of the original engineer's signed seal....

Unless a house or other custom building is a basic gable to gable run at a common width...almost all the trusses have to be designed and then approved (signed/sealed) on an individual basis...

Unless the space located above the cited ceiling is "living space" or has additional structure that supports living space...there should be no fire rating requirements on said ceiling...

This is exactly right. All the trusses for my shop and house were engineered by the truss manufacturer per the plans to support the required load. MY Shop trusses span a 30x30 with upper attic floored for storage. Trusses were made to accommodate at least 14 PSF attic storage in the center of the span. They design each truss per requirement of the house design and roof line. Hardly any, if any contractor site builds roof trusses anymore

 

[teejk]

I am admittedly ignorant on pole barns specifically but basic engineering and building codes still apply. My guess is that "attic" trusses are probably engineered for 20 lb per SF of dead load. 3 lb per SF is equivalent to about 2.5-3" of snow if that helps put things in perspective. I should probably add the typical disclaimer that you and you alone assume the risk of anything you do yourself without hiring a professional. :2cents:

I think that the term "attic" truss means that it is engineered to permit walking/storage on top. Just google "truss" or "attic truss" and enjoy (if you crave knowledge that is)! In the modern world they are so much cheaper than traditional rafter framing because they get to use lumber that would otherwise get rejected, can be built in a factory and install quickly. The engineering is rather interesting for a layman like me.

On a typical rectangle pole-barn with a typical 4/12 roof pitch, they come out of the box with not much thought (rather boring in fact). Our new house we used a "panelized" construction and the number of different trusses involved would make your head spin. It actually gave us closets in the upstairs bedrooms that are as big as most european bedrooms.

 

[steveessie]

Unless you order "attic" trusses, my understanding is NO load above. Standard pole barn scissor trusses would make it hard to do anyway. That steel option escaped me (even though that's what I have in my shop...a DUH moment). I haven't priced it lately but I think it might be comparable to drywall. And it looks nice...no taping, no sagging, quick install and LIGHT.

What "steel option" are you referring to? Where can I see a link and/or pricing on this? Can it be found at a typical Menards, Lowes, Home Depot? Interested in seeing and pricing.

 

[teejk]

What "steel option" are you referring to? Where can I see a link and/or pricing on this? Can it be found at a typical Menards, Lowes, Home Depot? Interested in seeing and pricing.

Didn't notice the Duluth location until now (how you liking our global warming???) Menards has a pole barn crew that I'm sure would love the work this time of year if it's inside!!! If like around here, you probably have a choice of others. They will be in and out in no time and can get the materials cheaper than you can.

 

[steveessie]

That's what I did in my shop...bright white steel, the ribs keep it very stiff and it's alot lighter than sheet rock. My contractor hates the thin "liner steel" (29ga maybe) so he did regular building steel (25ga???). Finished part of the shop is 40' long with trusses 8' on center...a 24' and a 16' did the job and it looks great. You can get it cut to length. You will need a poly sheet above.

A neat trick I learned from him (he does this for a living)...lay several sheets together. Mark out your screw holes and bang them HARD with a center punch. Peel the top sheets off to install but when the lower sheets start to lose the dent, slip new sheets underneath and hit the old dents again with the punch. It makes a very straight line and that dent is all you need to start the "pole barn" self tapping screws.

He learned the hard way that you can't drill them (rust issue). Amazing that you only have to lay out the screw holes once. Thought I'd share that.

Do you have any links for the material you used? Prices? Store? I like that idea.
When you say "poly above" are you referring to a vapor barrier? between the steel and insulation?

 

[oldbones]

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.

 

[teejk]

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.