1. #1
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    Default Building Const.: Lightweight Roof Truss

    I have a question and hopefully many of you will have an answer.

    Question: How harmful or detrimental is hand jacking or carrying by hand lightweight wood roof trusses from the ground level to the top of the dewelling or structure as opposed to using or renting some type of crane to do this work?

    The question stems from seeing a lot of new construction going on in our town and within mutual aid towns. How many carpenters, ex-roofers, or construction workers we got out there that can help.
    "The saw won't start, heh, grab the axe and start chopping"

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    What from I have learned thru a local chief here on Long Island who teaches a FANTASTIC class on lightweight wood truss constuction, I don't think hand carrying can do more damage than what's done to them in transit. They are transported with bindings jammed down around them putting more pressure on them, then they're lifted with a hydraulic crane & loaded into a pile on the ground while exposed to the elements. Can't get much worse than that!!

    If lightweight truss construction is becoming common in your area
    (where isn't it nowadays?!), you should consider getting more training on this topic. I don't know where you're located but if possible, it would behoove you to get this chief (an FDNY "squaddie") to come present this lecture to your dept. (good fund raiser - hold a seminar) & those in your area. If you want his name & a contact number, e-mail me direct (Firescueguy@AOL.com).

    Hope this helps you out. Stay Safe.

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    Being that I used to work in Construction I think I
    can give you a pretty good answer.

    Like was posted before those things are beat during
    transport, loading and unloading. But they are packed very
    tight.

    But, I have seen numerous trusses when they are being
    put up the wind gets them someone dosen't know what they
    are doing they get dropped, this is very harmful to the gusset
    plate which only goes in maybe a quarter inch. I very seldom have
    seen a house built by anyone that at least on gusset plate
    has not come off either during delivery or building.
    They are a cheap set up and can be very dangerous.
    When you are inside I hope on guy keeps his eyes on the skies.
    Or it might be on top of you.

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    Disagree totally with Fire rescue Guy.


    I have seen these lightweight wood trusses being handed up and have witnessed them slip and hit something, loosening the gusset or gang nail. Having written on and studied lightweight trusees for 10 years, it is more detrimental to hand jack or carry up. Contact Frank Brannigan, Vince Dunn, etc. who I have discussed this issue in depth with.

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    Thank you very much for all of your different points of view. Like I said we have a lot of construction going on the next town over from us. You go past a field one weekend and the next weekend a house minus the siding is up. I have seen other places where it takes a good two months or so to build a house.

    Is there anyone particular Lightweight Roof Truss design or style that is more dangerous than the other or are they all equally dangerous?
    "The saw won't start, heh, grab the axe and start chopping"

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    Is there anyone particular Lightweight Roof Truss design or style that is more dangerous than the other

    Not so much the design/construction as the use.

    An old fashion normal sized ranch house, especially one with interior walls that may not be load bearing but at least give you something solid inside, certainly reduce the risk.

    Start getting larger "McMansions" and "McDonalds" where large houses and commercial buildings start spanning longer distances, the danger increases.

    Then throw on additional permanent roof loads of A/Cs, etc on flat-roofed commercial occupancy, the risks rise further. Still gotta consider weight on a residential house sometimes -- especially if you have a heavy snow load!

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    Hi Brothers,
    The whole installation of light-weight, gusset-plate connected, 2 by 3 and 2 by 4 inch lumber construction is a nightmare to interior structure operations at fires. Not to mention their use as parallel chord members between floors of buildings.
    "Hand-jacking" as you call the process is just one more violation of the integrity of these flimsey constructs even before the fire gets there.
    Take a look at the site of construction of 1, 2 and 3 story buildings that are constructed as a single unit in your district.
    Forget the binding of the truss members - They are dumped on site in the old method of "jumping the truck" out from under the load and have the building material slam to the ground.
    If that is not enough watch as the framers take a small hammer (relative to the gusset plate) and hammer the 3/8 inch connecters back into the holes that they just came out of and deform the plate.
    If you are still not upset hang around it always gets worse.
    Next tell me the strength of two small dimension wood members being butted together in space as a tension bow member and held there by these "staples" called gusset plates.
    Next - get upset in public and see how fast the wood products industry comes down on your outrage.
    Interesting job this.

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    Default Wood truss floors

    I know this is a little off subject but I have noticed that some of the newer two story houses in my district have wood trusses between the first and second floor.

    Is this becoming a new trend? I presume that this would significantly impact the amount of fire/water weight that they can deal with.

    Any thoughts?
    I would...but no!

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    Parallel Cord Light Weight Wood Truss.
    No my friend this is not a new concept at least if you are not in the "job" more than 15 years.
    You MUST discover these during construction and take pictures for training and critique - Because these buildings tend to get sheathed very quickly hiding all the integrity points (or counterpoints) of the structure.
    The wood products industry are very defensive of these constructs. The national groups should keep track of injuries and worse to our firefighters in these buildings of toothpicks as well as those civilians or additional structural fire loss that you can "pin" directly on them being in place (ie: unnatural fire spread, rapid interior and partial collapse and more)
    But they are not new!

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    You MUST discover these during construction and take pictures for training and critique - Because these buildings tend to get sheathed very quickly hiding all the integrity points (or counterpoints) of the structure.


    Bravo

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    We have at least one or two developments in our mutual aid town that almost all of the homes have this Parallel Cord Truss construction. I have been taking pictures of these homes and I try to get at least a full time frame from when the basement is poured to when the sheathing and siding are put on and I also try to get one of each model in the development. I can only get around on the weekends to take pictures since I am out of state during the week so I am unaware of how the roof trusses go up. I am currently taking pictures of one of two commercial buildings being constructed that have Parallel cord trusses and Lightweight Roof trusses.

    How much damage can this really cause?
    Attached Images Attached Images  
    "The saw won't start, heh, grab the axe and start chopping"

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    To BOXALARM - Thanks

    To: Knight Hawk! I read where you said "How much damage can be caused?"
    We are firefighters - we deal every day with the "supreme rape" of the strength of a structure - FIRE!
    Truss assemblies are only strong as long as all the parts are in place. It is an assembly of triangles and if one side is compromised the entire system can fail.
    Now.
    If there are truss assemblies in the roof structure they are only a major collapse problem IF fire has extended to and is burning the truss assemblies. In the old days these were heavy dimensional lumber such as you find in supermarkets of old and religious structures. BUT today the strength is gained using 2X3 and 2X4 inch lumber in thise truss assemblies as chord members. They are held in place by thin tin gusset plates in which small (3/8inch) triangles have been pressed out like an old grater in the kitchen. These serve as "nails" and are pressed in during manufacture. Fire warps the metal and pulls the grips out. Poor workmanship is likewise compromising the integrity of the assembly.
    But that was the roof and you had to have a one story building or a fire on the top floor of a multi story building
    Now there are parallel chord truss assemblies of lightweight wood taking the place of full dimension beams and assemblies between ceiling of one story and floor of the next.
    Every floor is a lumberyard of toothpicks. If the fire gets to it through any opening including sheathing failure it roars through the total area of the floor and not just 16 inches on center one at a time like days of old.
    Floor failure can occur in as little as 5 to 7 minutes.
    No one said this job would be easy.
    Tom B

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    111 Truck your reply was in my opinion awesome. You have given me some really good food. The question of how much damage can this really cause is directed to the picture under it. I have other pictures of the trusses laying on the ground but they were all the same size and stacked neatly. The one major trend that I see more and more as I go out and look for new houses to photograph is that picture above. I guess the only good thing (if there is one) about that pile is that the weather conditions were pretty much dry and sunny no significant amounts of rain or snow before the trusses were put up. I have other pics. if you would like to see them let me know I can send them to you or post.

    Thanks
    "The saw won't start, heh, grab the axe and start chopping"

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    Thanks again Knighthawk,
    Actually I would like to see what you have taken in pictures.
    Either send them to me with your email address or put them here. Though I would hate to clog up the site.
    Tom
    Email address tfb111@swfla.rr.com

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    This is all very good information. As someone that was on a "framing crew" before I was a fireman I'd like to add few.

    All of the single and multi family homes that I built using roof and floor trusses had them built 2ft. on center as opposed to 16in. on center.

    The trusses are pre-made to fit a specific design, and when you start out with the foundation being a little bit out of square (dam masons) the top of the house could be a little bigger then the trusses. This will make the trusses only catch about half of the top plate. Then the boss says to "keep it flush in the front" the rear may only be on the plate an inch or so.

    You only get enough trusses to build the house. There are no extras, and yes they do go through hell before the framers get their hands on them. I have seen them in very bad shape so you just "scab" a stud on the broken pieces to hold it together and "make it work."

    I won't even mention gang nails.

    Some times the floor trusses are designed with a space in them to run HVAC duct. The problem is that the framers may not be paying attention and they put some on one way and some on another way and the voids don't line up. How do the HVAC guys fix it? By cutting pieces of the truss out with a sawsall.

    I would also like to mention something I've seen with TJI floor beams. They have little knockouts for plumbing and electric. But they don't pop out as easily as they should and they usually splinter quite bad when trying to do so. Sometimes they, like the floor trusses don't get installed all in the same way and the little pop outs don't line up. How do you over come this? Just blast through them with a hammer. This causes quite a bit of damage to the TJI.

    How can this happen when the homes must have a finial framing inspection? Well, in my day the pace of building here in Monmouth County New Jersey was insane. The Inspectors as well as the builders were under tremendous pressure to produce. There was a "Dam the Torpedoes, Full Steam Ahead" type of atmosphere. It's not right but it's the way it is sometimes, and it's something firefighters must be aware of.
    DKK
    Truck Man
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    "Above all, an assignment to a truck company should be considered a promotion."

    Chief John W. Mittendorf-1998

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    Default Thanks!

    Thank you Knighthawk for hosting this discussion and once again a heartfelt Thank You to 111Truck for passing on your knowledge. I assure you that this knowledge doesn't stop at me but gets immediately passed on to all those that will listen.
    I would...but no!

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    Baker FF/PM

    Thank you for your compliment. I feel that this subject is too important to be overlooked.

    How many times have we passed by homes going up and said "Man that is a REALLY BIG HOUSE!" I know I have said it enough and I finally decided to take pictures of these homes to study and to pass on information to others in my dept.

    I would really like to see this subject continue.

    I have one additional question how would you ventilate home or buildings with these roofs, from a roof ladder or aerial device?
    Last edited by Knighthawk; 02-16-2002 at 12:48 AM.
    "The saw won't start, heh, grab the axe and start chopping"

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    Ventilate from an Areial. Why because next time you see a
    house being built look at how the roof is done.
    The oldstyle was a 2x4 or 2x6 board with the trusses actually
    nailed into it. The new style is the prefab trusses put up
    with 2x4's put any where just to hold them so the dont' move
    so when the plywood you are standing on burns through and the
    hooks on your roof ladder are supposed to catch the top beam
    there is no top beam anymore, so you take a nose first plunge
    into the house.

    Did I explain that ok or was it a confusing as it sounds.

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    With respect to your question about lightweight wooden trusses, the amount of damage done during transport/use on the job site is what seems to me to be a non-issue. They are extremely dangerous under any fire conditions and contribute greatly to early collapse in a fire. It seems in this day and age of mass produced housing, this is the industry standard. Another point to ponder is that they are used not only in the constuction of single family homes, but also used in the construction of many fast food restaurants. The key to reducing firefighter injuries and fatalities is view all new construction during the construction phase and plan your tactics accordingly.

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    What is everyones ideas about the way these trusses are stored on the job site while the house or commercial building is being built.

    Take a look at the photo below.
    Attached Images Attached Images  
    Last edited by Knighthawk; 03-03-2002 at 01:16 PM.
    "The saw won't start, heh, grab the axe and start chopping"

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    Is the problem with lightweight trusses the way they're transported and stored before construction or just a problem by design alone? Should we feel better about working on top of or below a truss on fire if it was transported/stored properly? I imagine that these transportation/storage problem could speed up the time to collapse...
    However, would your strategy and tactics for fighting a building with a fully involved truss change if you could force builders in your area to store and transport these properly?

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    However, would your strategy and tactics for fighting a building with a fully involved truss change if you could force builders in your area to store and transport these properly?
    Excellent point. In my opinion it would not change the tactics but if we could make builders do everything by the book, it might save a little time and time on the fireground is everything.

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