I have either started or participated in some threads here and elsewhere, in which engineered trusses for complex roof frames have been discussed.
Someone made a comment in my recent thread that discussed trusses, saying that that most truss operations simply cannot get jobs with any complexity done, without making errors.
Why is that? What is behind these annoying errors?
Errors in factory-built trusses are annoying because of what it takes to do the workaround or fix. Phone calls, faxes, voicemails, emails, visits to the sites, all take place in a hurry-up merry-go-round, until the problem and error are clarified and understood, then time marches on while a new truss or trusses are engineered and built, then shipped.
Even in the best-case scenario, field-cuts are done, but those fixes have to be engineered and communicated.
What a way to build. Who dealt this mess?
Drive around a big megalopolis such as Chicagoland, or up and down that Washingon-to-Richmond corridor, and you’ll see scores of light commercial jobs going up with roof frames of engineered trusses. Bank branches, restaurants, hotels, multiunit housing, all that kind of stuff gets trussed roofs.
Are the commercial guys having the same hassle as the homebuilders?
Does a trained and experienced roof cutter, doing a frame for a big new multimillion dollar manse for a hedge fund guy, starting off with plans, a pile of two-by lumber and some LVLs, and his trusty CM Pro, have more resources than the guy at the computer, up in the office over the truss plant?
Why don’t we hear as much of “the roof cutter screwed up,” as we do about the truss guy?
Replies
If you get them made in Carlinville, there will be no errors!
If a roof-cutter screws up, it's usually a single board and the fix means cutting a new board, all of a 5-minute job and the mis-cut is used elsewhere.
If a truss order gets screwed up, it could be thousands of dollars of material and weeks of scheduling backups.
Not quite apples-to-apples.
If a roof-cutter screws up, it's usually a single board and the fix means cutting a new board, all of a 5-minute job and the mis-cut is used elsewhere.
That's a given, Mike. But what is behind those errors in the trusses?
Exotic pre-engineered building components get built every day in shops, and get erected every day on building sites, and things get done right most of the time.
When in college, I worked in a huge fab shop helping build the boxbeam components of the Poplar Street Bridge, the I-70 spans across the Mississippi at St. Louis. Up the river a friend worked in the PDM shops where they were building the component sections of the Gateway Arch.
Complex geometry in both, and stuff went together without hassles.
At my alma mater, there is a Gehry building that looks like this. Certainly a little tougher than some irregular hips and valleys.
View Image
So, enough of this blather. Why do truss packages for residential roofs come to the jobs, and have errors?
Today's truss design software packages are sophisticated and powerful. The technology employed in the cut, fit, and press areas of most truss plants is lightyears ahead of where they were twenty years ago.
What is behind the screw-ups?
View Image
"A stripe is just as real as a dadgummed flower."
Gene Davis 1920-1985
Gene,
I don't know exactly what screwups you're experiencing, but around here, most truss problems arise from two things. On other crews, there's problems from the framers not following the plans or not referring to the specs the truss designer gave them. They get to the roof and realize, Gee, maybe I shouldn't have fudged those dimensions way back down there on the first deck...
As for us, we frame on some pretty crappy poured wall foundations. These guys don't know the meaning of square or straight. Anyway, the truss rep never shows up on the job. Ever. He goes off the plan in his office and when changes get made on the jobsite, it's up to us to "make it work". Usually I have the truss specs right in front of me and make all the necessary adjustments as we go. I wish the rep would come out and field measure sometime.
You sound like you might be referring to the engineering itself though. Our trusses usually are engineered very well. The hips fit. Things are spec'd to plane together as they should. I think most problems arise from the framer and the truss rep not being on the same page. Of course, we only build what I would call average homes though. Not usually bigger than 3000sf or so. Some of the big stuff I see would be a lot more complicated to engineer.
As you might guess, I have some pretty strong opinions on this. And as with many questions, there is no simple "one size fits all" answer.My first thought regarding mistakes is that they often start with lousy plans. This past week I did trusses for a $300,000 duplex. The "plan" was hand drawn on 11X17 paper at 1/8" scale. No foundation plan, and no elevations. Believe it or not, there were problems with the trusses.Second is speed and cost. Everyone is being pushed to produce things faster and cheaper constantly. It's as true with truss companies as with anyone else. I'm constantly pressured to turn out jobs as quickly as possible. More speed means mistakes. I hate working that way, but mistakes are a fact of life.As Mike Maines pointed out, a stick framer can cut a board wrong and not think a thing of it. The board can be reused elsewhere. With premanufactured trusses, you only get one chance to do everything right the first time.As Sawdaddy pointed out, the problems aren't always caused by the truss company. Sometimes the framers do whatever they think will suit them best, not realizing what consequences their actions might have. They they call us and want us to fix the problem.Many problems are caused by the framers not taking any responsibility for anything. They don't want to see a truss layout ahead of time, for fear that they will be held responsible if there are any problems. It's better to wait until the trusses show up on the jobsite and play dumb.Another problem I see is indirectly related to what Gene said about "powerful computer software". People seem to think that because you're doing it on a computer there will be no errors. But that's utterly ridiculous. The same thing applies to truss design that applies to ALL computer work - Garbage in, garbage out. If things aren't put in correctly, what comes out will certainly not be correct.This brings up a related problem - Truss plant owners think that they can hire 20 YO kids for $8 an hour and have them doing truss design in no time at all. And they're partly right. Guys that age learn quickly, and can be cranking out designs in fairly short order. But they lack experience in construction, and don't really understand how trusses work. That in itself can lead to many problems.The plant owners are pressed to cut costs and be competitive, just like everyone else. That's why the company I work for tried to outsource truss design to Costa Rica a while back.Experienced guys like me are dinosaurs that the industry has little use for any more.Probably the reason I make most of the mistakes that I do is because of the volume of numbers I deal with - After a while they all start to look the same. You may mean to input 23' 4", but hit 24' 3" instead. Since there's no margin for error, that means that something is seriously wrong.If I send out a job with $10,000 worth of trusses and have one single digit wrong, I look like a complete moron. Unfortunately I do that on a fairly regular basis. It's REALLY hard to get every last digit perfect on a job when you're being pushed to get it done as fast as possible.Didn't mean to go on so long. But that will give you an idea of what I think about the subject....
It doesn't matter what YOU think, Harold. If you were married, you'd know that. [Red Green]
"At my alma mater, there is a Gehry building that looks like this. Certainly a little tougher than some irregular hips and valleys."And where would your Alma Mater be?
i have the good fortune to have built a "Gehry building", the walt disney concert hall in downtown los angeles.
as a member of ironworkers local 433 my jobs were structural detail, repairs for raising gang # 2 (Piedmont's gang) and then finally as a structural welder as we finished up.
years before this Gehry building went up i was working on a bridge job for a company called Kasler which has since been absorbed in a couple of incarnations into what is now the washington group.
i believe it was about 1993 in the early days of using computer CAD stuff in the field of heavy highway, at least in my experience in the major urban areas of california. i was a layout man for a company that built post tension reinforced concrete structures in earthquake prone zones, and the engineer by way of the foreman delivered to me a CAD prinout of the layout points for adifficult corner of the abuttment, a compund angle on a twist.
as i went through the process of layoing it out i was certain the printout was wrong but how to prove it to the engineer? i laid it out starting from several diffeent points, and put nails and string lines so the engineer could see it. then i went to get the engineer, he saw what i was talking about right away and went back to the office to correct his mistake. i wrote a detailed procedure for how to determine if a computer printout was in fact correct and copyrighted it in 1994. i then set about trying to develop it as a software program, but i couldn't get any software guys (even in the silicone valley in 1995) interested. too much work and similar programs were already out there in use by automakers etc. (volkswagen has a great one)
fast forward to Gehry in 2001, as i was interested in the programs used i went and talked to the guys who were "administering" the blueprint in the office and found out that they were a team of Australians whose job among other things was to make detailed printouts for the ironworkers building the thing as well as entering and adjusting the information gathered by the plumb up gang (shots with a laser transit of some type) to determine if we had the thing where it was supposed to be or not. The T shirt says "the ultimate challenge"
I found out the blueprint was on a very advanced 3D CAD software program that had been adapted to buildings from a swedish aerospace program, and it automaticall checked itself so that any change in the program would automatically cange any and all corresponding parts.
when raising gang # 2 had a structural beam that wouldn't fit, they hung it up there where they could, but one end was about 4" low. after the connectors reported it back down to piedmont, it was reported to the front office. there was a big pow wow out in the field about how to fix it, everybody was there, maybe even Gehry himself. (it could be i never met the man and don't know what he looks like)
eventually my foreman came to me and said "this is what they decided, and this is how you have to fix it" which involved removing some of the steel from a curved gusset welded to the underside of the curved piece of structural I beam that made up this piece, and did i mention it was about 80 - 90 feet in the air?
so i dragged my equipment up to the top of the world with the help of an apprentice, welder, torch, grinder and got prepared to work. when i got up there i noticed that the beam that was low on one end bolted up to a gusset on an intersecting beam, and that the gusset had a hole pattern in it that was offset from center. the first on the top was about 8" from the top but the first hole on the bottomk was about 4" from the bottom. with a quick check of my tape i determined that if i just cut out that gusset and turned it upside down the top of the beam that was too low would then be just right, and perfectly flush with the tops of the others.
i went back down and told the foreman, and he came and looked at it again (he was in on the first pow wow) and decided i was right and that he better go tell them in the front office that the welder charged to fix it had a better idea.
none of those guys trusted the computer, i knew the computer couldn't be wrong, i knew that it had to be something wrong that a human was able to effect, sure enough with an offset pattern of holes in a gusset to be welded in the web of a beam the human that placed the gusset before welding had it upside down.
needless to say i did all the repairs after that, and got quite a bit of respect for solving problems. in answer to your question, what is behind the screw ups is the human element, and the humans not understanding the system enough to be able to troubleshoot it.
thank you, i'll be here all week
Great story!!
Last big winery job I did I had a concrete laborer point out to the red iron crew that a beam bolted in place seemed to have smaller bolts and less of them than the other considering the spans involved.
Red iron guy looked at it, told his foremen who came to me. I called the engineer who checked his stuff.
Turned out a change in plans had occurred and the specs for that particular connection had been over looked. We effected a field repair and were on our way again. Human error again.
They can't get your Goat if you don't tell them where it is hidden.
Hey we have one of those Gehry buildings.
Errors in trusses? Why am I not surprised? Having visited several truss manufacturers, I am amazed that anything ever gets made right. Your talking the most primitive of conditions ... piles of wood stacked in an open field, a chop saw, and a work crew that is illiterate in Spanish, as well as English! Often there is an "RV" parked on site, where a dozen or more of these recent arrivals 'live.' A skilled guy shows up from time to time to make a template ... then leaves while the 'Hay-mans" get to work. There may not even be a porta-potty on site.
I don't know what truss plant(s) you have visited. But what you described is NOT at all typical.Most plants that I've been in have pretty modern equipment - $300,000 component saws and such. The idea that truss parts are cut on a "chop saw" is ridiculous - It's just not practical.
A wise man will make more opportunities than he finds.
Thanks - I needed to hear that! Come to Reno some time, and I'll show you the nightmares ....
I worked in a truss plant something like 30 years ago.
About a year ago I toured the truss plant of the main trues company I use. On one hand the truss jigs themselves looked somewhat familiar. On the other hand they had some awesome technology for cutting the wood. For example they had a big machine - call it a saw - that had 2x4 stock going in one end and perfectly cut pieces coming out the other at a fairly good clip - fully automated. I was impressed. Maybe the saw was the "component saw" Boss referred to. For something like a floor truss it was like falling off a log to have them come out to perfect dimensions.
OTOH, I thing most truss errors are design errors - not manufacturing errors. Not that the designers are bad - it's just that the whole process is that complicated...
GeneDavis
The answer is simple those writting the programs probably never built a house or can't do deductive reasoning..
My best friend makes a very comfortable living designing stairs and rails for companies all over the country.
$125.00 an hour and he tells them how many hours he worked..
Because of his reputation he's contantly busy and rejects more jobs than he accepts..
Doing roofs is at least as complex, but those guys aren't paid anywhere near that plus many companies ship those tasks to India or something like that. They scan the plans into their computer, click a button and they are gone.. They come back as build sheets for the factory to follow.. Instead of paying some guy a couple of hundred dollars to do it.. they pay someone in India $1.23 or something equally small.
Surprise errors are made converting from feet and inches to metric and back again. Plus the people in India have no idea of what they are really building..
Boss,
is this true ? are we outsourcing truss design to India ?
carpenter in transition
"are we outsourcing truss design to India ?"
The company I work for tried to set up an office in Costa Rica. They claimed they could get degreed engineers to do truss design and pay them about 44 an hour.
I haven't heard much about it lately. I think the language and technology barriers were too great to make it easy to do. They didn't really understand what they were being asked to do is my best guess.
I have no doubt others will try it (or HAVE tried it) and sooner or later someone will figure out how to make it work.
Change is as constant as the restless sea.
I think the difference between light commercial jobs and residential is the customization of houses. Most builder houses start out as a standard plan and per owners desires they hack out and add different hips, valleys, gables etc. as desired. So finding any two houses with the exact roof in a custom subdivision would be rare. But in typical light construction and particularly franchise operations it's all cookie cutter buildings. That is they've been done a hundred times before (think Wendy's, Burger King, etc.) and the kinks have been worked out. Also most commercial buildings I've seen around tend to be flat roof which eliminates another variable for error when the third dimension is not present.
""Does a trained and experienced roof cutter, doing a frame for a big new multimillion dollar manse for a hedge fund guy, starting off with plans, a pile of two-by lumber and some LVLs, and his trusty CM Pro, have more resources than the guy at the computer, up in the office over the truss plant?
Why don't we hear as much of "the roof cutter screwed up," as we do about the truss guy?""
Maybe because the roof cutter has the exact site built measurements to work off of. I have worked both sides residential and commercial. As others have said, unless everybody adheres strictly to plan and dimensions then the off site cut materials can only( OK not "only", I have seen truss plants screw up due to simple mistakes as well, but that is infrequent IMO) be wrong if someone didn't communicate the changes to the truss plant.
Roof cutters have the advantage of "boogering" things as they go along to cover previous mistakes rather than go back to square one and make it correct. Do that with trusses and if you playing by the rules you have to let the truss plant know what it is you are doing so engineers can check it out. Besides, most framers won't ever admit to making the mistakes in the first place and instead congratulate themselves on how well they "fixed" someone else's bad design or problem.
It took me years before my local truss guy trusted that I would deliver exactly what the plans called for, not close by 1/4" or 1/2" but EXACTLY what was called out . Once he started to trust I delivered then I really never saw him again . Delivered plans to him for the roof, he delivered the product to me and it fit. 99.99% if there was a problem it was mine in failing to read his prints and lay out correctly.
His horror stories of going to job sites and discovering buildings 4" out of square, 6" shorter or longer in span etc. than plans call for because some carp wouldn't fix things at the time a screw up was first discovered are legend .
On the commercial jobs I have done it is tougher but in those situations I sit with the actual field dimensions , a set of plans and my local version of Bosshog and we go through things, working out each detail until it all fits. Then it is up to my crews to keep to the final dimensions.
Shop drawings in commercial work are checked by a number of people to ensure things are correct, residential work rarely offers this advantage.
How many foreman or supers take the time to call the truss plant and say , "Hey , wall "X" is 3/4" from where it is supposed to be on the prints, what can you do to help us out here?" Instead they just keep it to themselves and then pass the blame off on the plant with a comment about the world isn't perfect.
Your analogy of the guy on site with a pile of lumber is something like comparing an assembly line auto from Ford with your one local bondo shop delivers.
Yes, one does have the advantage over the other in concealing screw ups and making it look good in the end.
Are the commercial guys having the same hassle as the homebuilders?
Probably not--commercial work has somebody (and I've been that dog'sbody) at the archy's office go over the entire set of shop drawings for the trusses, making sure that the plate elevations, peaks, overhangs, and such all match up. This can be an under-fun exercise when you discover the drafter at the structural engineer's transposed some numbers on the framing plan, too.
The contractors seem to approach problems differently, too. They seem to resist correcting uh-ohs in galvanized trusses (which are actually a tiny bit easier to fix in the field). But, they'll have taken saws to the wooden trsses without a second thought--until the engineer makes a field visit and calls the archy office with a "you ready for this?" call--ugh.
My experience is that about every one in the process--archy, engineer, contractor, truss plant--equally makes scary mistakes in the process. The trick is in catching the uh-ohs before the roofers get there.
"...commercial work has somebody (and I've been that dog'sbody) at the archy's office go over the entire set of shop drawings..."
That's a nice theory. The reality is much different, in my experience.
The truss company throws together some shop drawings and a layout, then sends it to the GC. They assume the GC will go over everything.
The GC stamps them "approved", and sends them along to the architect, assuming the architect will carefully review them. The architect simply stapms them "approved" and send them on to the project engineer.
The engineer also stamps they "approved" and they work their way back down the chain to the truss plant without anyone ever having looked them over with ore than cursory glance.
Of course - The stamps that the architect and engineer slap on the things say that they have only been reviewed for GENERAL conformance to the contract documents. That's their "out" so they can claim that they have no responsibility when the trusses are wrong.
So the trusses get built according to the incorrect shop drawings, and the finger pointing begins.
I've gotten burned that way MANY times. If I get a set of shop drawings back with no changes made, I automatically assume that no one has reviewed anything on them.
Humor is the affectionate communication of insight [Leo Rosten]
If I get a set of shop drawings back with no changes made, I automatically assume that no one has reviewed anything on them.
LoL! I've never seen a set of truss shop drawings that didn't need some sort of mark-up! <g> Bad part is when I have to send them over to the engineer's first, and they just send back their copy without looking at it, while working on the set I have marked up <shudder>
Maybe I'm just too dilligent and old-fashioned. Or have also been burned a time or two . . . (don't ask about the fast-food joint with the floor-trussed roof).Occupational hazard of my occupation not being around (sorry Bubba)
I think Boss answered it about as clearly as anyone ever could.
From my framing perch, I'll say that Boss is being too kind to the framers. My perspective is that most truss problems could easily be solved with foresight, even when things aren't quite right. Instead of thousand dollar repairs, most situations could be solved with a few minutes thought and some very simple adjustments by the carpenter.
The vast majority of my work has been with truss packages ranging from simple to complex. It is rare that I have not been able to work with the package, as delivered, and completed the job as intended by the drawings. In the rare case that there has been something wrong that couldn't be fixed, the truss companies have been very responsive, either sending out a new truss or sending out some very simple fixes that I normally could do without backcharging anyone. I have been paid to fix trusses too...but I don't ever remember a bill going past $500.
So, summed up, my experience with trusses has been excellent. The designers are sharp and normally get things right. Most of the errors I've discovered were mistake in MY THINKING. Because of that, I'm very, very cautious about calling for the rep. I hate being embarrassed and telling him "your right...I din't think of that".
With that said, I have noticed a difference in the documentation from one company to the next and most of my beefs would be in that department. I just have never understood why the truss companies wouldn't explain every basis of their calculations. There's not that much information needed: span, pitch, wall height, projection and heel. If they would print that information on every individual truss sheet and also on the plan layout view, a lot of field mistakes would be avoided.
Without that information, the field intallers are often forced to reverse engineer the drawings and that is where the mistakes are made. Then, the inevitable finger pointing begins.
Some have mentioned walls 6" out or unsquare foundation. Those are not truss mistakes. Those are general construction mistakes and competent carpenters make the adjustments early on in their game. This turns "major" problems into easily solved minor problems. Its the guys that don't plan ahead that end up having "huge truss mistakes".
Our program to eliminate those situations were simple. We required that the trusses be dropped onsite before we started. My personal system was this: establish the square mudsill lines and then compare them to the truss drawings and identify changes. I then verify that the trusses matched the truss drawings. So, before the first walls were built, I knew exactly where any deviations were and made the necessary adjustments in theory, before the actual construction started. I would know the exact height of every component on the house, starting from the mudsill, through the peak. We knew every detail of the cornice system: projection, sizes and elevations. All these were calculated from the new realities posed by "walls that are 6" out" and out of square foundations.
Bob's next test date: 12/10/07
Gene
I mostly do interior remodels and deal seldom with trusses, but what I always wonder is this.
At job sites the trusses get delivered, next day I drive by all the trusses are up and sheathing is started. Fine, but leaning in a ditch or against the porta potty are 5 or 6 trusses, what is with that. The plant was nice and sent extras, (sometimes they are different sizes) so did the framers just forget to put some in? It looks like a novice rebuilding an engine and is done and has extra parts wondering where they go.
The time frame is too short so it can not be that some were damaged and new ones were made up, I am talking one or two days, They are not for a back porch or something because it will be months later and the trusses are still sitting there and the house is being sheet rocked.
Just wondering why if you need 40 are there 46?
Wallyo
We have had replacement trusses shipped the next day when problem arises. They certainly don't ship extra trusses but sometimes changes reduce the ability to use the trusses as shipped. Bob's next test date: 12/10/07
i have actually had extra trusses delivered on two different jobs. one was a simple scissors truss the other was an "extra" triple ganged addic truss @ no extra charge.
the thing that sucked with the extra addic truss was that they shorted me a regular truss. But they brought it out the next morning, don't recall loosing any time on the job so not a big deal.
It appears to me that there are several points in the process susceptable to disconnects.
My input to the factory includes a preliminary truss layout showing scale, loads, bearing points, etc. The factory guy throws an estimate together. At this point he has not put a lot of time into it, not knowing if the bid will be accepted.
I accept the bid and turn him on to get started. The engineer is in another state. The sealed drawing that was presented to me is probably no good at this point. The real design may or may not look like the bid.
I've just installed a set where one of the bottom chords is showing cracks. Maybe it was a forklift or maybe that board just had knots in the wrong places. Maybe the fabricators saw it and just kept going.
I guess that common to all this is that is takes time to ensure that the final product does what it is supposed to do. Everyone in the process is wanting to move forward and not "waste" time double checking or picking up the phone to communicate. As long as it is more acceptable to fix problems than to prevent them there will be errors.
The fix for a split bottom chord is so easy that even if we saw one on the first day of framing and could easily get a new truss ordered and delivered, it wouldn't happen that way. The engineer would simply send out a nailing pattern for a simple scab, unless the bottom chord was part of a bearing point on a girder. Bob's next test date: 12/10/07
Agreed, an easy fix that is already done. It would have been a waste of diesel fuel to have a replacement truss sent to the site.
Since I have worked in a "factory" in 95 degree, 95 percent humidity, I know how things go. I also know that it won't do anyone any good to complain about the truss. Nothing would improve, no process would change. But there was a point in time that the truss could have been yanked off the line. Instead it became one more item added to my punch list to resolve.
I still have an option to build plywood gusset trusses. Lead time for metal plate trusses for me at this time is over two weeks. Plywood gusset trusses can be built in the same day without a delivery truck. (And they will have an engineered sealed drawing and calculations). So metal plate trusses are not a show-stopper.
" I know how things go. I also know that it won't do anyone any good to complain about the truss."
I have to disagree with you there. I honestly wish MORE of you guys would complain about truss quality.
If a framer calls us with a problem like that, we generally send someone out to fix it on site. Often the same day, sometimes the next day.
I like that they take guys out of the plant and make them go to the field to face the customers and fix the problems - I think that's the best way for them to learn.
If you just fix it and don't say anything, then nothing will ever change.
Consultants are mystical people who ask a company for a number and then give it back to them.
That's the sort of thing that will keep you in business during a recession.
Some folks want to learn how to keep and build their business. Some folks don't want to be bothered.
If all a young kid knows is his little world at his work station, then he doesn't see the consequences of his work. Seeing the end work site gives his work some meaning, and that other people are depending on him to do a good job.
Jim Allen mentioned having trusses dropped on site before or during framing. That is , at least in my experience, rarely done here.
Our truss plants rooftop deliver so we would have to pay for the extra trip for them. (I know this varies from local to local because I know I was stunned when I helped my brother in Fla. and discovered at the last minute I was responsible for a crane.)
Plus there is simply no place to set trusses on site on many sites. Our plants often won't guarantee correct trusses without site verification of plan dimensions so that means not even a build until you have walls erected. How about the rest of the country?
Dropped on the ground or roof top delivery?
Delivered in advance or delivered when the walls are ready?
They can't get your Goat if you don't tell them where it is hidden.
Gene, I live downhill from you and have framed 100's of houses and apt. in Syracuse.
That being said there are certain truss companies I will not name here that always get it wrong on complicated frames.
If you email me i can explain further.
>Delivered in advance or delivered when the walls are ready?<
dropped. would like to see aerial delivery like the DW
order (Oand delivery) depends on how confident i am of meeting the dims in the drawing or knowing the variations thereof.
Calif.: Delivery truck has built in crane, sets trusses on plates.Colorado: Some kind of roll off truck. Get your own lift.Like you, thought they all were set on plates.John
and often in Colorado the trusses can't be delivered to the site...
we're not talking the plains segment of Colorado now....
they're dropped and assembled into manageable units then air lifted to the site and set into posistion via helicopter......
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!Forget the primal scream, just ROAR!!!
and i thought it was scarry with a crane! I cant imagine setting and bracing trusses on the plates with a helicopter.
Must be very trusting carps.
cake and pie...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!Forget the primal scream, just ROAR!!!
"Dropped on the ground or roof top delivery?"
We do both. Some people like it one way, some like it the other. We ask when each ordfer is placed.
"Delivered in advance or delivered when the walls are ready?"
Most of the time the trusses aren't ordered until the framer is ready to start framing. So the framer is often ready before the trusses are.
Sometimes you get the elevator, sometimes you get the shaft.
When things were real busy 4-5years ago, we had as many as 8 houses framed, waiting for trusses!
We always have them dropped and hire a boom truck. This allows us to prep the gables or to assemble the girder trusses and attach the monos.
Someone asked about extra trusses left after the house is framed, those are 99% a problem with the truss plant. It seems like one manufacturer can't read the plans<G>
The ones for the builders in my area are dropped on the site, and usually before the walls are up. Occasionally before the slab is done!
i was a roof cutter but im sure theres much better ones around then me. I was called in before trusses to cut roofs.
Im somewhat of a ding dong with math but i had my way of stepping off with my steel square that never failed.
Older guys taught me the square and i found old books to study.
Much as im bad with math at least i know it but i see people all the time that mess up yet are convinced there right.
If one is to cut roofs one needs a building square , plumb and the walls need to be straight and parallel to each other.
even then i cut 2 test rafters set them at each end to check and a few places in the middle..
When i framed a building knowing it was getting trusses i was fanatic about my measurements.
I dont mean to imply slow its just as fast to do it right as wrong. .
I see so much sloppy framing its a wonder the trusses fit at all.
The sheetrocker was telling me how much trouble they have fixing framing mistakes.
I would be ashamed to have a sheetrocker spend time fixing my framing or adding nailers yet they HAVE to figure in
From my experience any truss problems I thought I had was from me thinking I was smarter than the computer. I learned real quick that the computerr is never wrong. As long as the dimensions on the print match the dimensions on the truss layout sheet Ive never had a problem.
Gene:
I only read about 1/2 the posts...
Anyway, I build mostly homes with roof trusses. Many get floor trusses too. Once I get pricing and select a truss company and make a commitment to them I get the shop drawings to review and submit for permitting before the trusses are built. During the permitting time period is when I do my checking. Can't tell you how many times I've had a house framed from slightly different shop drawings (and truss set) than was actually permitted.
You are right though - very complex trussed roofs are very prone to errors. Luckily the truss company I usually use is very responsive and generally gives me 24 hr turnaround for a fix (often with a verbal within a few hours) and within 48 hours (2 working days) in the rare instance that a new truss actually has to be built. I have never been charged for any of this.
Also, having been around this stuff enough, I have an idea of what the engineer recommended fix will be and have on occasion winged it - of course with a follow-up verification and letter from the truss engineer.
Regarding light commercial I once baby sat a 24 unit condominium building while one of my co-workers went on vacation. I showed up the Friday before for an orientation. Framers were framing a somewhat complicated hip roof with several "jogs" and overframed gables. The main roof was almost done but the overframes had to be added. The framers first erected a few of the gable ends and common trusses with a crane. Then the valley sets (over frames) were to be put up there on the following week with a telescopic fork lift that was more or less a permanent fixture on site (as opposed to the rent by the hour crane). Anyway, on that Friday I said to the super who's site it actually was: "Doesn't that gable end look higher than the main roof?". Well, you know the rest of that story.... Turned out that the architect had drawn a 6:12 but marked it on the drawing with an 8:12 (with that little triangle). The PM had some pipe dream of selling the wrong sized common trusses to someone who wanted to build a garage... In the end the framers had to remove maybe 40 trusses they had installed and roughly 100 trusses ended cut up and some used for back framing but most just plain ended up in the trash. It required a extra dump of the rolloff bin. What a fiasco!!
and who ate the cost of the new trusses, Owner, Archy, Archy's E&O insurance, Builder or truss plant? Just curious.
TFB (Bill)
Not sure - the regular super was back from vacation by the time they got to that point. Last I heard the truss company was going to pick up some of it and the architect had admitted some fault in the matter too. A contributing factor to the situation was that my company had made changes to the initial plans (at least a year earlier in the game) and although these changes were implemented on the plans by the archi he missed the nomenclature on the little triangles.
The thing was that the truss companies shop drawings clearly showed the error. To me it was totally weird - it seemed like the drawings had been printed off the printer and NOBODY had even looked at them. Not the truss designer who should have been asking "are you sure this is what you want", not my co-worker or PM, and definitely not the archi. Seems like maybe even the town's permitting office might have even said what the heck is this???
Just goes back to my initial point: Check your truss design drawings closely before saying "yes, build them" to the truss company. Still many errors aren't so obvious and are much harder to catch.
For starters I verify the spans of the trusses, the roof pitches, and the width of any features like cathedral ceilings that might be built into the roof trusses. I also require my truss company(s) to show plumbing drops (in the case of floor trusses) and duct chases on all truss layout sheets. I also verify the locations of any attic platforms or storage areas. Most all of this stuff I've learned the hard way.
Just goes back to a basic premise of building - the first place the building is built is in the mind of the builder - as he sits and scrutinizes the plans closely. EDIT: whoops.... and I guess It should have built in the mind of the designer before that - although (not being a designer/archi/etc.) I'm guessing they tend to think more in terms of conceptual things.
Edited 6/9/2008 7:29 am ET by Matt
"To me it was totally weird - it seemed like the drawings had been printed off the printer and NOBODY had even looked at them."
That would be exactly what I would typically expect on about half the commercial jobs I do.
It's like people think that as long as they don't actually LOOK at the drawings, they have no responsibility for anything that's wrong.
The longest day soon comes to an end.
Gotcha.TFB (Bill)
The type of fiasco you described is the same type of error that I mentioned should have been caught by the carpenters onsite. Instead of fixing/changing 140 trusses in the air, they should have been discussing the changes needed while standing next to the truss pile on day one, or day two of the frame job. One of the big lessons that I tried to impress upon my foreman (carpenter) was that he needed to look at, understand and verify every truss in the pile BEFORE WE FRAMED THE WALLS AND OVERHANGS. I've never framed in an environment where I sat bare trusses onto bare walls and maybe if I did, I wouldn't insist so vehemently about checking the truss package for accuracy. One of the checks that I always did was to put my framing square on the truss to verify the slope. That number also got verified by the calculation for drop from the HAP to the top of the fasica. The top of our fascia was our datum line for all the parts relative to the exterior trim package. So, a 2" difference in pitch would certainly ring some very large bells and at the very least cause me to ask a few questions before I'd figure my cornice. Bob's next test date: 12/10/07