we’ve built a number of on site trusses, built- in pre-load crown, plywood gussets glued and NAILED, and considered them better than factory-made,…and apparently needing some mindless, repetitive work to do…
so now someone tells me the strenth of the pre-mades , which sometimes seem flimsy, comes from the compression they get when made…
zat so?
also, I notice here that site- mades may be frowned upon by the BI….
Replies
We have built many on site trusses in my lifetime and I still consider them much stronger that factory made. I have sat and watched these guys make these trusses in the shops and I am not impressed with this preload business. They do have the load positions down to a science. But is not hard to figure out with the span tables. The difficult part with building them on site is making them all exactly the same. We eventually had to stop building them on site because the building departments wanted an engineer's stamp on the truss. I really do not like using trusses because the shops here do not make them consistent. We end up with different HAPs on one side of the building because we set the other side to a string. Of course the trusses we built were not 40 feet long. I think the only problem you will have is not having an engineered stamp on your truss.
James Hart
"I think the only problem you will have is not having an engineered stamp on your truss."
James , thats an awful big statement. It should not be given to all as advice.
What you two should be considering is liability. The buiding inspector is trying to save your butt.
There will be plenty said in this thread. I have not at all said my peace.
Tim Mooney
Tim, I agree all the way. Liability is very important, I suppose I was taking some things for granted. One should know what he is doing and the engineer has to take responsibility for what he approves. It is difficult here to get an engineer to approve site make trusses for the simple reason that there to many framers who do not know how to build them and he does not want the hassle of inspecting the built trusses. The funny thing is, many times after we have sticked framed a roof the inspector will ask us to truss brace the rafters. In other words, he wants the bracing to look like web bracing in a truss. So, in effect, we have built a truss without the metal plates for the joints.
James Hart
James, differences in framing are part of the deal. It's no different with shop built trusses. How you handle the differences is a matter that's debatable. Experimentation is essential to finding the best solution.
Theres a lot of mistakes made by us framers when dealing with trusses. One of the most common is building one side of the house perfect, while not knowing, nor accomodating what the other side is doing. In my earliest years, we used to hump the trusses and set them all by hand. Of course, most were small by todays standards...usually 32' long and 4/12. The "heels" did vary somewhat. We minimized the truss to truss defects by stringing a line from gable to gable at the peak! since all peaks started out perfect, the drastic wandering at the heels didn't seem so large any more.
That one thing alone would help most truss installers.
We now use different criteria. Because I cut all my tails level, the exact tip of the tail should start out precisely where my subfascia meets my fascia. If we have both overhangs up, it is relatively easy to split the differnce...again reducing the drastic difference between trusses to a manageable level.
I suspect you don't put your overhangs on first....our techniques would be almost impossible.
blueWarning! Be cautious when taking any advice from me. Although I have a lifetime of framing experience, some of it is viewed as boogerin and not consistent with views of those who prefer to overbuild everything...including their own egos
Additionally, don't take any political advice from me. I'm just a parrot for the Republican talking points. I get all my news from Rush Limbaugh and Fox and Friends (they are funny...try them out)!
Blue, your are exactly right about setting trusses by the peak. We have done that several times. All the trusses we set have the overhang built onto them. I am not sure what you are talking about when you say you build the overhang first. I've been in Alabama all my life and I'm sure there are some techniques we need to learn. We set the trusses and then proceed to put on the sub facia. Of course, we have to put a string on the face in order to make it straight. The problem with setting them to the peak is that most of the trusses we set these days are set by a crane and the string gets in the way. We end up setting one side to a string and dealing with the other side with shims are whatever is necessary to make it right.
James Hart
The problem with setting them to the peak is that most of the trusses we set these days are set by a crane and the string gets in the way.
Set your gables up, then use the crane to lay your trusses down on top of
each other, piled up to one end of a gable(laying down).This leaves room to pull from
the pile of trusses to place individual trusses on the lay out with the string in
place. ( this works on trusses that can be carried by 3 people , one on each end and
one in the middle). Run your string after all the trusses are up top. I think you
would use less crane time ($)this way, but of course this doesn't apply it the
trusses are to large.
Hopefully Blue will come in here and set me straight on how he would do it.
:-)
I've only set about 10 houses worth of trusses, but I'll pass along my favorite method just in case you're interested.
I like to get one wall as perfectly straight as possible. Then line up the heels of the trusses on that wall. Since the trusses are all perfectly identical, there's no need for a string line.
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O.K., I'm kidding there. I know that trusses are SUPPOSED to be consistent from one to another, but often aren't. Quality control is one of my pet peeves with the industry as a whole.
I wish there was an easy answer to this. Sometimes the differences aren't too serious, and you can live with it. Other times they need to be dealt with.
If you run into problems, my first suggestion is to CALL THE TRUSS PLANT. Get them to send someone out to look at the trusses. Personaly I like to have them send out the foreman who was in charge when the trusses were built, but they don't do that too often.
If you can wait, try to get the truss company to send out some of their guys to fix the problem. If you fix it yourself and they don't know about it, nothing will change.
And one more point - Be reasonable, and don't exaggerate the problem. I went out to look at some trusses Tuesday where the carpeter claimed they were "Way off". He said where the trusses cantilevered out 7' in one place they were bowed up 1.5". And trusses that should have planed out were built at COMPLETELY different pitches.
What I actually found was some lumber crowned down 1/2" on one truss, and an upwards slope of 1/4" on the cantilever. They certainly weren't perfect, but nowhere near as bad as he'd said. I don't like it when people lie to me.In short, it is a paradoxical truth that tax rates are too high today and tax revenues are too low, and the soundest way to raise the revenues in the long run is to cut the rates now...The purpose of cutting taxes now is not to incur a budget deficit, but to achieve the more prosperous, expanding economy which can bring a budget surplus [John F. Kennedy]
I like to get one wall as perfectly straight as possible. Then line up the heels of the trusses on that wall. Since the trusses are all perfectly identical, there's no need for a string line.
Part of the problem of trusses isn't really a problem of trusses. The problem? It's those heels! They tend to wander high and low......OR DO THEY?
Most carpenters think the heel is ALWAYS at the end of the bottom chord. The reality is that the heel is a an actual height and if you put a framing square on the bottom chord and penciled a line in at the actual height that you wanted, the end of the chord might, or might not, be there.
blueWarning! Be cautious when taking any advice from me. Although I have a lifetime of framing experience, some of it is viewed as boogerin and not consistent with views of those who prefer to overbuild everything...including their own egos
Additionally, don't take any political advice from me. I'm just a parrot for the Republican talking points. I get all my news from Rush Limbaugh and Fox and Friends (they are funny...try them out)!
"The problem? It's those heels! They tend to wander high and low......OR DO THEY?"
I don't think they ALWAYS vary. But they certainly do sometimes.
It's generally a problem with the saws. Crooked lumber is hard to cut on automated saws. But the guys at the tables should catch the problem and take care of it.
Trouble is, there's no incentive in the truss industry to make good quality trusses. Contractors want their trusses fast and cheap. That's all we hear 98% of the time - Faster and cheaper, faster and cheaper. Honestly, I'm surprised sometimes that quality is as good as it is given the system that's in place.
So the guys in the plant are pushed to build stuff as fast as possible. They get PRODUCTION bonuses, not QUALITY bonuses. So unless someone puts pressure on them to stop production to fix a problem, they're only shooting themselves in the foot if they stop and fix a problem.
The only solution I see to this problem is if the customers insist on higher quality. If they drag the plant manager out there to see the problems, it becomes much more "personal" with that manager. Then he's more likely to put pressure on the plant guys to build better trusses, so he doesn't have to go get chewed out by the customers again.
That's why I stress if you have a problem with the trusses, CALL THE TRUSS COMPANY.The first job of leadership is obtaining power. The second job is delegating it to subordinates. [JBR Yant]
Ok, Im home.
I have to be muffled mouthed about it for several reasons. One this is Breaktime , second I dont need to be argueing with a truss guy, and third Im a building inspector.
The truth is though we did do it for a number of years. I mean like a bunch . Back in the old days we even made some for people . Scary I know. This started back 40 years ago and sure isnt the same as today. I dont even remember a building inspector back then or a truss plant in town. We had a lot of lumber and of course there was rejects. We had a building business and a lumber yard. We did logging as my dad was mainly a logger most of his life. We live in yellow pine country as the Ozarks are full of it . So all that is home grown. We built and sold a lot of FHA houses, 235 I think it was. We built a truss jig and did all of our own.
Im not as negative as you about it because we ignorantly did it. We sure didnt know any better back then or at least I never questioned it . We mass produced a 24 ft truss and sold it on special every day for barns and shops. I went to the mill myself and hauled the lumber to the yard and graded it . We were in the lumber selling and using business because we did buy it very cheap and it was just down the road.
I know there is fabulous money in trusses . That part is the gimic. Its a no no now to build them ourselfs, and the truss comapnies are cleaning up. Literally. That my friend is a fact.
Tim Mooney
I wouldn't argue what you did 40 years ago was right or wrong. Certainly the liability issue was much different back then. Even 20 years ago was different.
But when you say there is "fabulous money in trusses" I couldn't disagree more. The margins are actually pretty tight. Truss companies go bankrupt on a regular basis.
Two of the 5 companies I've worked for have gone bankrupt. And the other 3 aren't pulling in huge margins, I'm fairly sure. But they're both companies that have a long term history, are well financed, and are expanding.
I do realize that margins may vary from one area to another. Maybe it's different where you live.
Last time I saw a report from the WTCA, I think they showed an average profit margin after taxes of about 7%. (Based on a survey they did) That's not a lot for a business that you might have to invest a million bucks in just to get started.The first method for estimating the intelligence of a ruler is to look at the men he has around him. [Noccolo Machiavelli, The Prince]
Thats equally fair enough.
I guess it gets back to what licensed and insured guys gripe on here about non compliant contractors. Bidding against them.
I can see a huge overhead and expense to a truss plant. If I were to make a jig and saw out parts even though Im not automated, theres a huge difference in cost. Seems the last time I figgured it it was close to half what a truss plant charges. Of course they have a delivery charge that they eat in most cases.
Ive been working on mechanics law this morning as an inspector. Heres my take on the subject;
Theres a homeowner , a builder , and a truss plant . The homeowner only has recourse with the contractor if its a bib job as a whole. Homeowner sues contractor. Contractor sues truss company. Truss guy hires lawyer. The contractor will get stuck and hopefully the truss guy will. The bearing of responsibility is with the builder first in a contract job.
My answer is ; It is up to the contractor if it doesnt get caught by the inspector. If its inspected and there is fault ,its still up to the contractor. Either way , its the responsibility of the contractor. The inspector has no liability. Neither does the truss company until its proven to be them and getting that done might take some doing. Certainly some expense on part of the contractor. I find it the contactors decision, unless specified by the building authority.
Tim Mooney
I'm not sure I understand all your comments on liability issues. I guess having a truss company involved does give homeowners someone else to sue.
FWIW - In the almost 20 years I've been in the business, I've never known of a truss company that was sued for anything they did wrong. Every lawsuit was over stupid stuff where the attorneys were just trying to get all the cash they could.
Maybe not directly related, but an interesting point regardless.
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I don't have all the numbers on how much overhead is for a truss plant. But going from memory, it's something like this:
Lumber: 40%
Plates: 8%
Direct Labor: 20%
Overhead: 15% (Buildings, saws, forklifts, machinery, etc.)
Shipping: 8%
That's mostly from memory from when a past employer discussed it with me. So it may not be terribly accurate, but gives you a rough idea.
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We could talk all day about whether it's cheaper to build your own trusses or not. But the topic would likely be awfully controversial and I doubt any conclusions would be agreed on. I've had enough controversy lately and hope to avoid more. (-:
I have enjoyed hashing things out with you, though.Here is the test to find whether your mission on earth is finished. If you're alive, it isn't. [Richard Bach]
The cost of building trusses is a moot point .
My point of liablility is that in this state , the owner of a building doesnt have class action against a sub contractor when a general contractor paid them . My interpatation is that trusses may fall into that category. The contractor is liable first but not last. Also , the sub cannot place a lean on an owners building , nor could a truss company that was hired and paid by a general contractor. Now the contractor can go after anyone he hired or paid. The general contractor warrants the whole shebang period. Thats why we have licensed and bonded contractors that have liability insurance as required .
I said that to say this ; A builder could build his own trusses if he took full responsibility by warranty and the above. Unless an engineer was was required by the building inspector. Most of our state is not under inspection.
I dont condone building job site trusses . Just wanted to mention that the general is responsible any way. In cases of no inspections , he could make that decision.
Tim Mooney
The liability thing is a bit beyond me. Heck, they're just gonna sue anyone who has deep enough pockets anyway.
Two minor points -
In Illinois, a truss manufacturer CAN file a lein. Guess that varies from state to state?
The only reason I brought up the overhead issue was that I thought you might be interested.
They can file suppier's liens here in Michigan.
blueWarning! Be cautious when taking any advice from me. Although I have a lifetime of framing experience, some of it is viewed as boogerin and not consistent with views of those who prefer to overbuild everything...including their own egos
Additionally, don't take any political advice from me. I'm just a parrot for the Republican talking points. I get all my news from Rush Limbaugh and Fox and Friends (they are funny...try them out)!
In the 60's, and maybe before and after, the State Extension Service offered a book with pre-engineered designs for trusses. As I recall, these were mostly intended for agricultural buildings, but they were ultimately used by some on houses.
My Dad and I built a barn and hay shed with them. All the components were joined with plywood gussets with a very heavy nailing pattern. I remember most pounding nails for hours on end.
They probably weren't cost effective if labor was considered, but the structures Dad and I built and those built by others are standing in good shape today. (Of course, the cheap availability of Old Growth Doug Fir in those days probably helped).
Well, the S-235 was a farm home plan. The Extension Service is where these plans came from and they were free. Ive got a bunch today that I saved. Ive seen in the detail drawings and blue prints [real blue prints] the shedule for the truss. They were engineered I suppose to be in the set of blue prints.
I have saved some blue prints back to 45 years old. Most of the old ones are 30 to 35 however.
Ive also seen the truss design for barns and loafing sheds as it was called. Seems there was a small booklet. It also came drom the extension service.
We picked up a Botich dealership in 1970. They set us up with the whole line of tools , plus nails and staples. We put some trusses together with the N16 nailer with 6s in it. That is a very heavy gun. Mostly we used the decking stapler which had heavy duty 2 inch staples. Both guns of course were rapid fire , but the stapler had a sound of its own. Ive got a new stapler thats not near as heavy or carries the distinct machine gun sound the old one carried. [Im sparking some memory here.] We set up oilers on the compressors to oil these guns through the hoses. To last day in and day out they needed to be spitting a small amount of oil we were told by the rep. In production of trusses we used two staplers. We didnt glue anything but we sure shot a lot of metal in them. 6 staples per piece being as much as 24 staples in the top of a W truss. As you say , it was a heavy nailing pattern. I remember three family members making a set of trusses in an afternoon. We all knew what to do. But of course they were all simple trusses and not of the types used today. They all had shallow pitches and were never very long. What I am calling a simple truss.
Tim Mooney
Actually Butch, your idea has merit, provided that the roof is relatively simple. My old buddy Forest used to build the same tract house for Pulte and he would simply have th crane drop the entire rack up there in one place.
He didn't need the string idea, but our trusses that we get around here are plenty good enough to set without strings. Also, because all our overhangs and fascias are completed before we set trusses, its relatively easy to see that the plane of the roof isn't fitting correctly.
blueWarning! Be cautious when taking any advice from me. Although I have a lifetime of framing experience, some of it is viewed as boogerin and not consistent with views of those who prefer to overbuild everything...including their own egos
Additionally, don't take any political advice from me. I'm just a parrot for the Republican talking points. I get all my news from Rush Limbaugh and Fox and Friends (they are funny...try them out)!
provided that the roof is relatively simple
Yeah, your right, that only would work for a straight gable
Blue, I just do not see how you build the facia first. This is a new one on me. What do you attach it to? What if the trusses have a down tail versus an even with the top plate tail? Could you share some insight or is there a past thread?
James Hart
James, we simply figure out exactly where all the parts of the overhang are going to land, and then build it on the wall before we raise it.
I'll post some pictures after I get back..I have to go sheath a cone today.
blueWarning! Be cautious when taking any advice from me. Although I have a lifetime of framing experience, some of it is viewed as boogerin and not consistent with views of those who prefer to overbuild everything...including their own egos
Additionally, don't take any political advice from me. I'm just a parrot for the Republican talking points. I get all my news from Rush Limbaugh and Fox and Friends (they are funny...try them out)!
I await your pictures. This ought to be interesting. I think I am going to learn something.
James
"They do have the load positions down to a science. But is not hard to figure out with the span tables. "
There are no "span tables" for trusses anymore. Those went away with the latest revisions of the NDS.
With the standards we have to use for design now, it would be almost impossible to calc the things by hand. They aren't done as pin joint models anymore.COMMAND: A suggestion made to a computer.
This ought to get good ! I cant wait.
Tim Mooney
so TIm, I know you're a BI, so tell me more - can an on-site be good enough? is the engineering stamp requirment meant to weed out the bad ones, and only incidentally weeds out the good ones as collateral damage? or is an on-site truss just no damn good, no way, no how?
First thing , truss companies have taken work away from the carpenter. One boss on the ground and a bunch of dummies can raise simple trusses. It happens everyday . Once cutting the roof is out of the picture , building most simple houses are for dummies. Carps are not needed, and not used most of the time [here] . That statement is not a mistake , it stands. Builders live off profits. They will minimize costs where ever they can. They may act like how great thou are on this site , but I have yet to meet one that wasn't trying to make licks off several things to make a living. Expenses is one major factor. The truss guys are trying to make a living too and will defend themselves to the outer limit.
Most of the time building our own isn't an issue. For most people the truss plants are the answer. For small simple trusses where we own the building , site building works well for some , but not recommended. I don't know what an engineer would cost on a set of trusses, so the cost might be scary. Theres not a lot of money to be made on one house anyway. Now on a four plex that's long and narrow , hmmm , that's dream money. On a subdivision of apartments , bring on an engineer! Picture 1 thousand trusses the same size and all simple.
Yes building on site is an option , but engineering is recommended . For a BI its a must .
Tim Mooney
"First thing, truss companies have taken work away from the carpenter."
I don't see it that way. Trusses just allow carpenters to do more jobs per year.
Certainly trusses change the way things are done. But so have pre-hung doors. Not many carpenters know how to make their own windows with counerweights anymore. Or make moldings with a hand-held plane set. There aren't many experts around anymore than know all about how to design a outhouse. Or a log cabin.
Times change. And the jobs that carpenters do have changed.
BTW - I can't resist poking a little fun at you. In looking over the thread on building your own trusses I referenced earlier, you said the truss industry was a "gimic business".
Still feel that way? (-:Computers can never replace human stupidity.
Im fixing to go away for the weekend. My wife is saying lets go.
To a point , yes.
Tim Mooney
thanks to you and all for the feedback - understand, I don't like building trusses...at all...I don't see why we do it , unless the boss just didn't get it together to order them in time.
I agree with the thought that we have better things to do...
toledo,
Here in WA you can build your own, as long as your plan is including the stamp. (Plans checkers got to know it's gonna work and all.) I think once you get your design approved, your good to go just like a truss mfg. would be.
I would think you could easily recoup the cost of the stamp by the second job if you were building all the time.
Peace
I have quite a bit of experience with job site built trusses, factory built trusses, and stick frame roofs. I have built trusses on angle iron grid tables with a single hydraulic gang nail press and on plywood jigs with plywood gussets glued and stapled.
Cities will protect themselves from liability by requiring that a truss plant that certifies the engineering for their truss roof system manufacture the trusses. Their trusses come with installation instructions. Some builders prefer truss roofs for the same liability reasoning, especially if they don’t pay well enough to attract qualified framers. The only place these days that I know you can site build a full roof truss system is where there is no municipal building jurisdiction.
Trusses work on opposing compression and tension forces. For a roof system to truly have strength it has to have a number of trusses that give it form and strength. A single typical truss is not as strong as many trusses tied together. After the system is installed it is compressed by gravity to stress it and strengthen it. I do not know what they are referring to about compressing them at the plant unless they mean putting the camber in the bottom chord.
I am confident in my own site built trusses but I do not get to build them much these days.
Over the years, I've been through several threads about site-built trusses. They generally end up with someone pissed off at me because I don't think it's a good idea.
So dare I hope this one is different? Guess we'll see.
A long time ago I posted in a thread about Building Your Own Trusses which pretty much covers what I think. No sense repeating it all here.
One minor correction to that is where I said there's "no statute of limitations on liability" - I actually meant there's "no statute of limitations on ENGINEERING". As long as a structure exists, whomever provided the engineering is responsible for it.
"...someone tells me the strenth of the pre-mades , which sometimes seem flimsy, comes from the compression they get when made.."
That's total B.S. No truth to it at all.
Trusses get their strength from TRIANGULATION. Each truss is individually engineered for lumber size, lumber grade, plate sizes, and locations. The plates are pressed in, or rolled in with large rollers. (Lots of guys seem to think we beat 'em in with hammers)
If they seem flimsy, it's becauuse they are. Until they're on the walls and have plywood nailed to the top chord, they don't have much strength. But they don't NEED to.
Leaders are like eagles - they don't flock ... you find them one at a time
Boss, thanks for the link to the old thread, especially to see the old Tim Mooney...I'm still new around here and bound to ask a repeat question - guess I'd better check archives first....I wonder when every question will have already been answered....
"...I wonder when every question will have already been answered...."
Well, there certainly are plenty of repeat questions around. That's why I keep links to stuff I've posted before - So I don't have to re-type it every time the subject comes up.
But that's no reason not to bring it up again. There are always new people, new ideas, and different opinions. And no one of us is the ultimate authority on any subject here.As soon as a man climbs up to a high position, he must train his subordinates and trust them. They must relieve him of all small matters. He must be set free to think, to travel, to plan, to see important customers, to make improvements, to do all the big jobs of Leadership. [Herbert N. Casson]