STRUCTURAL QUESTION– There are two hypothetical buildings. Both are one story. Both have a square footprint, 24×24 feet. Both are simple one-room plans, such as a workshop or storage area. But one building has a steel post in the exact center, with a steel beam running across the interior to support the roof. The owner of the building does not mind the post in the center of the room. The question concerns the overall cost of each structure. Does the plan with the center post and cross beam save a lot of money, a little money, or no savings at all, over the building that has no interior support for the roof?
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I don't think there would be any real savings. Unless it was going to be a flat roof in snow country.
Dave
With a roof span of only 24', the house with no beam would be cheaper. Roof trusses will span the 24' and, if it's a simple gable roof, very cheaply. Besides, if I were to use a beam for 12' spans to carry a load like that, I'd stick with wood or engineered lumber.
918 Contracting - Residential Construction
as long as standard trusses could span it......that's the cheaper/easier/faster way to go.......for a simple gable. 24".......as hog would say....truss it. Jeff
* Jeff J. Buck/ Buck Construction/ Pittsburgh, PA *
2nd Generation Buck Const, 3rd generation Craftsman
Careful there JB - I've never said that trusses were the answer to everything.
Most things maybe....................(-:
I don't think this question has a simple answer. On a building this small, the only reason to add a post would be if there was a need for storage overhead. In that case using a beam and stick framing the thing as opposed to using clear span attic trusses would probably cost about the same.
I would like to point out that adding a bearing for a roof truss almost never makes them less expensive. I can go into why that is, if anyone is actually interested.
I start reading this thread thinking trusses and, "Why go to all that extra work to add a post under trusses?"
Obvious answeer was post adds cost
Until Boss mentions attic storage.
Excellence is its own reward!
OK- Suppose the footprint were enlarged to 28x28 ft: would the centerpost now make the roof structure cheaper?
Roof trusses, man. Even at 40x40, roof trusses. You really want to use a beam that badly? Put one in for decoration. Westlam makes nice appearance grade beams.918 Contracting - Residential Construction
Roof trusses.!!!!!!!!!!!!!!!
Or if this is just a mental exercise for you on all these variables, then run the numbers yourself. We don't do no stinkin' free work.
LOL
Excellence is its own reward!
Doesn't matter how wide the building gets - Adding a center bearing almost always makes the truss more expensive instead of less expensive. There are exceptions, of course.
The reason is that adding a center bearing forces you to put a joint at the bearing location. Then you end up increasing web sizes and plate sizes around the bearing location. So it rarely makes the trusses less expensive - Even up to 70' span.
On the other hand - If any of you *DO* get into larger buildings - Say 60' and up that have a center wall. Have your truss supplier bid an alternate for 2 mono trusses instead of one large truss. The reason I suggest this is that 2 mono trusses can typically be built a lot cheaper than one big truss. And the smaller trusses are easier to handle and install.
Just out of curiosity - Why did you bring up this question, anyway ???
Edited 4/1/2002 6:35:06 AM ET by Boss Hog
Thanks for all the answers. My experience in construction is limited to a year in high school architectural drafting and reading Fine Homebuilding. It looks like the truss is here to stay. Everywhere I see new homes going up, I see a pile of banded trusses dropped off a flatbed truck. No more piles of 2x lumber, that will be individually cut and put into position by roof framers>>>>> My financial "ship" might come in, to where I might possibly be able to draw up plans for a little retirement shack and I am trying to get ideas. While the truss is undoubtedly an economical solution to many building problems, it isn't always the best thing, esthetically. There are "appearence grade" trusses, but they call 'em "Timber Framing," right? ;-)
Now I'm really confused! What are you talking about.....asthetics? Normal basic home construction....trusses have bottom chords...which replicate ceiling joists...which get drywall attached to them...which makes for the top room ceiling.
Normal basic stick framing....has rafters...and ceiling joists.....which get drywall attached to them...which makes for the top room ceiling!
Are you talking about cathedral ceilings? That too...can be done with either trusses or stick framing......but the ridge on stick framing has to have bearing the whole way down......and not necessarily a midspan post....as the ridge can be structural...as in it supports it's own weight...with out sagging.....but ya still need the support at each end.
Trusses are just made up with a "exterior roof pitch" and an "interior ceiling pitch".
Now I've confused myself! Thought we were talking about the basic box here. What's with the exposed framing ala timber? Jeff * Jeff J. Buck/ Buck Construction/ Pittsburgh, PA *
2nd Generation Buck Const, 3rd generation Craftsman
I'm an owner builder of a 24x24 built 28 years ago. It was built with a low slope flat roof (1st mistake) and a center post w/ beam...SECOND MISTAKE. The first has been corrected with an over build, but I still loathe the post.
If we are going to take a few minutes for comparitive take=off, why not draw out the ergometrics/use plans for the building before calculations?
somewhere out in left field.................................Iron Helix
Depending on the span, a center beam and post suporting flat framing would be cheaper. Until you try to waterproof and drain the flat (or low slope roof). Then the costs soar, and the quality will always be subject to the performance of roofing membranes and scuppers. Trusses man, trusses! They will always be cheaper, particularly since the ability to carry floor loads on the bottom chord is a nominal upcharge....that's not a mistake, it's rustic