Here’s another truss for y’all to look over. Just like on the other trusses, this is NOT an engineering problem.
Think more about how this one would be handled/installed in the field, and what might go wrong.
Murpy’s law kinda stuff.
Politics is the art of looking for trouble, finding it, misdiagnosing it and then misapplying the wrong remedies.
From building boxes and fitting face frames to installing doors and drawers, these techniques could be used for lots of cabinet projects.
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Replies
Well, if member W3 is there for a reason - some sort specific load at that location, looks like it would be awfully easy for the truss to be installed backwards.
"...if member W3 is there for a reason"
It's definitely there for a reason - There's an interior bearing at that location.
"... looks like it would be awfully easy for the truss to be installed backwards."
You got it. Maybe that one was a bit TOO easy.
This is how the truss would look if It were designed correctly(IMHO Then it wouldn't make any difference if the truss were flipped around - The webs are symmetrical, and it would be plated symmetrically.
View Image
How do you get a man to do sit-ups?
Put the remote control between his toes
Boss Hog, do you work in the truss industry? This is my first post here, but I've been lurking for while. Ive been in the truss indstry for few years now, now in designing, but still wet behind the ears I guess.
Any ways, I got to disagree with you here. Truss manufacterers aren't responsible for the builders craftmanship, the builder should now how this truss is to be oriented. They're supplied with all the neccesary paperwork, and should be paying attention to those details. The way you designed this truss adds unneccessary plates and lumber which costs the manufacterer money. And if its part of a run where other trusses have the same profile, but no intirior bearing, that would be way overkill. We are a small shop that does almost all costum work, if we were to bend to every builders demands like this most likely be the difference in making or not making a profit.
Welcome to the board. Yes, I'm in the truss industry. Have been for basically 20 years. I work in central Illinois. Where are you at?Your opinion is certainly welcome. There have been a couple of other truss guys who have wandered through here over the years. But none of them have hung around long. .I definitely don't agree with you that it's the builder's problem to get the truss oriented correctly. Framers don't typically understand trusses to any great degree. And it's hard to pay attention to every last detail when you have several guys working and have a $100 an hour crane truck sitting there. You're more focused on getting the job done. Mistakes are unavoidable. So if I can do something like this to head off problems in the field, I'll do it. It's one of the things I do that cements long-term relationships with my customers. They appreciate the extra efforts I make to prevent problems for them.I did NOT add any extra pieces to the 2nd truss design. If you look back at the pictures, both the first and 2nd truss have 8 webs. Since the 2nd one it symmetrical, there are less saw setups. So it might actually be cheaper AND a better design.I would agree that if there were other trusses WITHOUT interior bearing is might be a different situation. Every house must be taken on a case by case basis. Honestly - I would probably make the trusses interchangeable. What if the trusses without the interior bearing get switched with the trusses that were designed for the interior bearing? Again, I like to try to make trusses "mistake proof" when possible.
Why do you press harder on the buttons of a remote control when you know the batteries are dead?
The truss is heavier on one side due to orientation of offset bearing point. I usually load these guys three at a time w/crane. I would place the control line to the light side and use two boom straps to help balance the load.
Thanks for an easy one, Boss.
There is a 50-50 chance of installing it a**-backwards. I have ten of these in my truss package, coming up soon.
The most likely field problem is for it to be installed backwards. I gather the extra web piece is so that it can tie to a load-bearing wall. If installed backwards that piece will be flopping in mid-air.
That ones too easy Boss!
That truss cannot be rotated. It has a bearing point that must be properly positioned. Any competent truss guy would automatically know that if it can go in wrong, it will.
Send the doggie bones.
blue
PS Guess how I know that?!!!
Just because you can, doesn't mean you should!
Warning! Be cautious when taking any framing advice from me. There are some in here who think I'm a hackmeister...they might be right! Of course, they might be wrong too!
If you rotate a truss and install it backwards here where I live, you are likely to have a he!! of a hump in one side of the roof and a crater in the other. No way you're going to get all the necessesary bracing on in straight lines either.
I made this statement to the manager of a local truss company once in a dispute over poor quality trusses: "So what you're telling me is that trusses are not for use in a quality built house"
His response: "That's correct."
I only use 'em when I must. And then it's kicking and cussing the whole way.
k
When trusses are symmetrical, do you mark them as to orientation? That way they could all be installed the same way around as they were assembled on the table, which would make any small setup errors the same on each side of the roof. Sort of like crowning all the studs to the same side of a wall.
-- J.S.
John, I'll answer that.
NO!
I swear, I don't know why they do this, but I think they are just trying to mess with our minds, but this is true. This is probably my biggest peeve with truss people: They don't indicate which end is front or back. When a truss cannot be rotated, they say so, but they don't tell us which end is which...all they do is warn us not to rotate it.
So, when I read that note, I start investigating which end goes where, but I don't have a base of information to tell me which end is which. That drives me nuts. I swear, I've had some trusses that took me an hour to determine it's orientation. You'd think that the first method of identifying which end is which would be by looking at the spec sheets. You would figure that they would orient each sheet the same way in the packet, but Nooooooo! That's too much trouble for their computers!
Just in case you didn't notice, I've written in larger font to register my frustration.
I've worked with trusses for 30 years now and the paper work hasn't changed that much. Some truss companys are better about clearly labeling their trusses, but the vast majority are very weak about that practice. Only in the last year or so have we routinely received a comprehensive layout that is legible. Another huge issue is clearly identifying the heels (height above plate). Often, they don't indicate this most critical dimension. The next critical dimension is plate height. Often, they make the carpeneter onsite figure out what height is needed. Since they have to know their total overall height anyways for any given point, it would be nice if they'd clearly lablel the heels and plate heights.
I've got a few dozen more beefs, but I'll leave it at that. Suffice to say, I've wasted about 1000 hours of my life, interpreting the poor truss company's paperwork. I know which truss company's are the bad ones and I never hesitate to recommend the better one,s while trashing the bad ones.
blueJust because you can, doesn't mean you should!
Warning! Be cautious when taking any framing advice from me. There are some in here who think I'm a hackmeister...they might be right! Of course, they might be wrong too!
"You'd think that the first method of identifying which end is which would be by looking at the spec sheets."
Actually you probably can if you know where to look. With the software we use, there's an "X" on the LEFT end of every truss on the layout. Ask your supplier about it.
"Some truss companys are better about clearly labeling their trusses, but the vast majority are very weak about that practice."
That also ticks me off. At the last company I worked for I convinced them to send one of the plant guys out to a jobsite to help them sort a complicated set of trusses that weren't labeled. The framers gave him all kinds of hell, and it made a big impression.
"The next critical dimension is plate height. Often, they make the carpenter onsite figure out what height is needed."
I don't agree on that one. Seems to me the PLANS should give the plate heights. It ain't my job to figure that one out.
If the plans don't give exact heights, I think the framer or GC should meet and work that out before framing starts.
Forty-two percent of all statistics are made up on the spot.
"The next critical dimension is plate height. Often, they make the carpenter onsite figure out what height is needed."
I don't agree on that one. Seems to me the PLANS should give the plate heights. It ain't my job to figure that one out.
If the plans don't give exact heights, I think the framer or GC should meet and work that out before framing starts.
See what I'm talking about John Sprung?!!!
Boss, we all know the plans give a wall height. The typical wall height I see written on a plan says "8' wall height" or 9-0 wall height, or 12'-0 wall height. Now, we all know that the actuall wall height is NOT 8-0 or 9-0 of 12-0! So, my dilema is this: I know for sure that my 8' wall height will use 92 5/8" studs, but I'm not so sure what height they'll think an 11-6" wall is! I can use some logic to create a common ratio, but what if the truss guy uses a different logic sequence.
Since I prebuild everything including overhangs, porches and many elaborate features, it is disastorous to find out later that the actual rough top plate is something other than what we 'THINK' it should be. So, off too the huge complicated truss pile we go. Instead of simply looking at a chart somewhere that could easily be automatically generated, we have to reverse engineer the entire system to learn and understand the truss designer's tendencies. Even then, we don't actually 'KNOW' that we are correct unless we dig out the exact trusses that are dropping down and changing plate heights and put them together.
Not knowing all plates heights, from the designer's point of view costs me easily four or five hours per job on most of the type houses that I work on. That's a wasted $500 bill because you don't want to press a button.
Yes, this is a very aggravating thing to me and I know for sure that in my contracting life, I've been bitten in the butt by weird plate heights, so I NEVER proceed without building a wall until I've field verified the trusses.
Oh yeah, that cute litte "X" detail....I'm offering a better solution. Just put these little words on the spec sheet. "front of house", back of house, or east , west, north, or whatever the plans show!
"X"?!!! That is a joke isn't it?
blue Just because you can, doesn't mean you should!
Warning! Be cautious when taking any framing advice from me. There are some in here who think I'm a hackmeister...they might be right! Of course, they might be wrong too!
"I know for sure that my 8' wall height will use 92 5/8" studs, but I'm not so sure what height they'll think an 11-6" wall is"
So why not just TELL the truss guy what height you're planning on framing at? Why is it up to the truss guy to figure out what you want to do?
I would agree that there's no standard when it comes to 8' nominal walls versus 10' ones. Some guys will frame the 10' walls at 10' even, and others will frame it at 10' 1 1/8".
Our layouts often aren't done until the walls are being framed. Somebody needs to decide what to do ahead of time to avoid this problem. Tell the truss guy what you want to do ahead of time, or write it on the print when you give it to them.
I would admit that any truss guy worth his salt should ASK about this too. But there are lousy truss guys just like every other profession. Some of them probably just don't care.
"Instead of simply looking at a chart somewhere that could easily be automatically generated"
I'm not sure what kind of chart you think could be "automatically generated". But our software doesn't "automatically generate" ANYTHING.
Again, all that's called for is some communication. Tell the truss guy what you want ahead of time. Waiting to see what you'll get when the truses show up is just asking for problems.
Regarding the "X" detail I mentioned - Check out the attached picture. On the ends of the truss you'll see the "X" I mentioned. That's ALWAYS the left end of a truss when we produce a truss drawing.
The truss comanies you use may or may not be set up like that. But it's worth asking.
Death to all fanatics!
So why not just TELL the truss guy what height you're planning on framing at? Why is it up to the truss guy to figure out what you want to do?
Boss, the trusses are already onsite before I know I'm doing the job or before I ever see a plan. The plans indicate a wall height, but occasionally the truss enginering dictates that a slight adjustment of the wall height must occur.
I would agree that there's no standard when it comes to 8' nominal walls versus 10' ones. Some guys will frame the 10' walls at 10' even, and others will frame it at 10' 1 1/8".
I would frame all walls adding that 1 1/8" for floor finish and ceilings, but my ideas aren't as important as the truss designers. He's the guy that has actually created the truss, now I have to get the info from him or reverse engineer it. Half of the truss companies around here give us the info in a comprehensive form. The other half can't be bothered. Guess which companies I reccommend to builders and homeowners? I have more leverage with homeonwer self builders: we tell them we are going to upcharge the labor price if they use certain lumber yards and truss suppliers.
Our layouts often aren't done until the walls are being framed. Somebody needs to decide what to do ahead of time to avoid this problem. Tell the truss guy what you want to do ahead of time, or write it on the print when you give it to them.
That is 180 degrees different from the way we work. We WOULD NOT frame a single wall without knowing the EXACT height of the heel because all of the cornice system is going on the wall before we raise it.
I'm not sure what kind of chart you think could be "automatically generated". But our software doesn't "automatically generate" ANYTHING.
Maybe "automatic" is the wrong word. You would have to push a button!
All I would need is the total overall height for each truss heel. If you want to assign a value of zero to one point in the system, then show the plus or minus elevation at each end, I'd be estatic. It's obviously a very simple geometric valuation. If you cant "automatically" do that, your system can't design trusses.
Tell the truss guy what you want ahead of time.
I want the truss gus to tell me two more items than they do now. I wan't the heel height and the overall height above the first floor on every truss sent out.
Don't you agree that this information would be critical and helpful to the guys in the field?
Regarding the "X" detail I mentioned - Check out the attached picture. On the ends of the truss you'll see the "X" I mentioned. That's ALWAYS the left end of a truss when we produce a truss drawing.
I've never saw and "x" detail like that. I'll start looking for it, but I think I would have noticed it at some point and wondered what it was.
I feel better after ranting a bit. It still doesn't re-imburse me for the many thousands of dollars that I've wasted over the years. I hope you feel better knowing that you've seriouisly dipped into my pension!
blueJust because you can, doesn't mean you should!
Warning! Be cautious when taking any framing advice from me. There are some in here who think I'm a hackmeister...they might be right! Of course, they might be wrong too!
"...the trusses are already onsite before I know I'm doing the job or before I ever see a plan."
Seriously ??? I've never even HEARD of things going that way. Around here our production schedules are so tight, we generally don't have the trusses BUILT until the day before they're installed. (At least during the busy season)
Our salesmen typically meet with the framer onsite to measure the foundation and go over details before I even know an order exists.
"Half of the truss companies around here give us the info in a comprehensive form. The other half can't be bothered. "
That does sound like some pretty lousy service. I've NEVER turned down questions from framers/GCs, unless they had nothing to do with the trusses. (One guy asked me what color fascia material he should use, for instance)
"Maybe "automatic" is the wrong word. You would have to push a button!"
It's a little more than "pushing a button". I think people tend to greatly estimate what truss design programs can do.
"All I would need is the total overall height for each truss heel. If you cant "automatically" do that, your system can't design trusses."
Again, I think that's really an oversimplification. Software doesn't "automatically" do much of anything.
"Don't you agree that this information would be critical and helpful to the guys in the field?"
I have no doubt it is. But where you and I part ways on is who's to blame here. Seems to me the GC should be providing this information to both you AND the truss manufacturer.
Why not just ask for a set of shop drawings on the trusses before you start a job? Lots of areas require that they be produced anyway. And they should have the vast majority of the info you're looking for.
If you can't get that, I wouldn't start the job.
Let him who is without aim cast the first stone.
blue.. we must work in idiot land...
every truss we get comes with stamped plans, with all of the engineering background, every truss has plastic labels pointing out bearing points
all bracing points are marked..
every truss has a front .. and a back the front is the same as the orientation of the truss plan.. and the labels go on the front
when the inspector comes thru he wants the engineered plans there and he confirms that the truss was installed the way the designer intended..
the engineered plans become part of the job file in the inspector's officeMike Smith Rhode Island : Design / Build / Repair / Restore
>> every truss has plastic labels pointing out bearing points
all bracing points are marked.. <<
never seen any of that... Matt
Not all manufacturers use the tags. They have tags for bracing, bearing points, concentrated loads, and lots of other things.
Here are a few examples:
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The art of leadership is saying no, not yes. It is very easy to say yes. [Tony Blair]
"When trusses are symmetrical, do you mark them as to orientation? "
Some companies do. I wish they ALL did.
Many of the companies I have worked for paint the left end of the truss with spray paint. That's to insure that all the trusses are turned the same way when they're on the house.
Trusses are NEVER perfect. Sometimes there's a bit of a crown or a dip in one side of the top chord. Or the peak is a hair off center. If all the trusses are oriented the same way it's no big deal. But flip a few of them around and all the sudden they don't plane out well.
So if one end is painted it makes them easier to line up correctly.
The only thing necessary for the triumph of evil is for good men to do nothing. [Edmund Burke]
First, I guess I have been fortunate in that all 3 of the truss manufacturing companies I have worked with provide good layouts. Sometimes it's a hassle hunting around the pages to see if there any notes that are of specific interest - I wish they would put those in extra bold type or something... This is why I review the sheets before "truss day". Here, the truss plans must be submitted at permit time, so I get the layouts ahead of time. Looking for the load points is step 1.<!----><!---->
At least a few of these companies ship the trusses piled up in the order they are to be installed on the house - I'm talking about relatively simple houses here... so, if you walk up to the pile of trusses with a can of spray paint before they get unbanded and mark one set of tails, problems can be headed off.<!---->
I have had trusses installed backwards before - but caught it before the sheathing was installed, so it wasn't a real big deal. To me though, looking at a truss sheet for non symmetrical trusses and other anomalies is framing 101 and the guys who installed the trusses backwards didn't get "invited back"... On the other hand some hip roofs, etc, can be real head scratchers.<!---->
If the first truss pictured above were installed backwards, and the layout sheets were reasonable, the DA finger would be pointed at the framers though, although I might have a conversation with the truss guy, asking " could have this been done better?"<!---->
I'm just a super though, so although It's my job to identify possible problem areas ahead of time I can't be there every minute. I do pride myself in being the kind of guy who is reasonably available though, and one who has the answers to whatever questions may arise for all the trades...<!---->
Matt
Edited 4/2/2005 8:03 am ET by DIRISHINME
Somewhat related Qs for Boss and Truss-rod...
In my state, all truss drawings are stamped by a PE. Is this the case in all states? Does the PE even look at the drawings, or is he just passing his authority and right to use his stamp on to qualified individuals - who are presumeably using some kind of fancy truss design software? Matt
"In my state, all truss drawings are stamped by a PE. Is this the case in all states?"
I think they're all different. In Illinois, all truss designs are SUPPOSED to be reviewed by a STRUCTURAL engineer, not a P.E. But it's largely ignored because nobody enforces it.
Some of the counties or towns with LOCAL building codes require specific things. But that varies so much from one place to the next that there's no "normal" procedure.
I thought about being rich and it don't mean so much . . . Just look at Henry Ford, all those millions and he never owned a Cadillac.
"So what you're telling me is that trusses are not for use in a quality built house"
His response: "That's correct.""
Would you mind letting me know who that guy was?
I'd like to go smack him upside the head...
Don't look now, but there's one too many in this room and I think it's you.
Not as bad as I did at the time. I had to fur out all ceilings in a 3000 sq ft ranch and make about a dozen other repairs, hire a structural engineer to approve some of them. About a weeks work for me and a helper. My drywall man used all the tricks and hardware and we still get lift causing my mouldings and work to look like crap. Thats been about 6 yrs ago and I still get call backs to fix stuff in that house. In other words I'm still paying the price. That son-of-b...... is probably laid back on a beach somewhere now and I'm still dealing with it.
I came to the conclusion that trusses are for pole barns and agricultural buildings where lift is not a problem and slick smooth ceilings don't make a dam. He admitted as much to me during the dispute.
Recently I used trusses over a garage on a house, rafters every where else. Guess where the humps and bumps in the roof are. I'm not raggin on your trusses or your company. You may build a far superior product. By I avoid em like the plague. This coming week I will be installing trusses on a 50'x50' airplane hanger. It's a dutch hip with a 5 in Pitch. I'm just wondering what's gonna come up with them. But hey, it's an airplane hanger. Maybe I'll report on them later next week.
kcoyner
>> My drywall man used all the tricks and hardware and we still get lift causing my mouldings and work to look like crap. <<
I have come to the conclusion that the way the drywall is nailed to the ceiling makes all the difference in the world - specifically, it shouldn't be nailed to a bottom truss chord that is any closer than about 12" to an interior partition wall. You probably already knew that...
Matt
Thanks Matt,
Rick always stays back 12 " per National Gypsum Handbook. He uses the clips as well. Still it's a battle with trusses.
k
Yea - I know what you mean. And the worst part is that once truss uplift occurs, there is nothing you can do about it better than some marginal cover up methods.
Hey - edmucate me some. I know what drywall clips are, but tell me how they can be used to reduce truss uplift?
Matt
The thread I did on Truss uplift has some links to WTCA publications. They ahve some suggestions for dealing with it afterwards.
Experts say 86% of people who watch pro wrestling on TV think it's real.
This explains why Wile E. Coyote gets so many 'Get Well' cards.
Well, that answered the q about drywall clips, but 2 of the 3 links were dead and I hunted around a bit but couldn't't find anything other than "preventing partition separation". No "how to fix" it.
Anyway, I think trusses both for floor systems and roofs are here to stay, and can only gain market share. The reason being that 2x10s and 2x8-24's are only gonna get more expensive and harder to get. Also, I think floor trusses for a 2nd story floor system are great because you can run most all your 2nd floor ducts inside the building envelope. Matt
matt.... i've never experienced truss uplift..
i wonder if it has anything to do with the fact that we never build any ceiling without furring it.. also we bury our trusses in a lot of insulation..
for the past 10 years or so, we typically use 20" (settled ) of cellulose
i think piffen said somewhat the same thing.. he furrs his ceilings also
the sequence is (typical ):
trusses at 24"oc
1x3 furring at 16"oc
then the partitions nail to the furring..
we use a LOT of scissors trusses
Mike Smith Rhode Island : Design / Build / Repair / Restore
The way you describe it, assuming that the partition walls are attached very well between the cap plate and the strapping, I can see that the strapping might flex along with the truss movement. On the other hand, you plaster - don't you? There is no flex in that what so ever - is there? My hunch is that it would be the insulation and that your building techniques offer very little opportunity for migration of moisture from the building envelope up into the roof systems. Around here, there is not so much focus on energy efficiency, and people just won't pay for that kind of stuff - at least not in new construction. I wish they would though...
It's my understanding that in truss uplift it's the shrinkage of the vertical/angled truss webs that pulls up the bottom chord... Maybe in scissor trusses you get less of this since the length of the webs are somewhat minimized, and if you are putting in 20" of cels, these webs have, maybe at least 50% of their area buried in the insulation which minimizes moisture content swings... We do some scissor trusses, but more regular fink trusses.
Also, some of the truss uplift that I have seen was on houses I didn't build, so didn't really know what construction techniques were employed. Matt
"It's my understanding that in truss uplift it's the shrinkage of the vertical/angled truss webs that pulls up the bottom chord."
The generally accepted theory is that the top chord expands and the bottom chord shrinks. It has nothing to do with the webs.
The bottom chord is warm and dry, wrapped in insulation and down near the ceiling.
The top chord is cold, and gets some condensation in it. That makes it expand.
I saw a demo once where a guy took a small truss (6' or so) andmade truss uplift occur. He drilled a series of holes in the top chord, and dripped water into them.
The truss was set up on blocks, and had a dial indicator under the center of it. As the top chord soaked up moisture, the truss arched upwards.
I feel so miserable without you, it's almost like having you here.- [Stephen Bishop]
boss.. that might be another factor in our never seeing truss uplift
we ventilate our soffits.. provide a path to the ridge and vent our ridge
Mike Smith Rhode Island : Design / Build / Repair / Restore
The few houses that I was involved with the building of and ended up having truss uplift had good ventialtion. I'd suspect poor placement of deadwood, and nailing of sheetrock.
Matt
I wouldn't be surprised if roof orientation has a bit to do with it. That can make a significant difference in the attic temps at certain times of the year.Beyond that, keeping the bottom member as cool as the top (furring would help here) is probably important: If heat from the house warms the bottom member and dries it out more you'll have more uplift. Of course, this is offset to some degree by thermal expansion, so it gets kinda complicated.
"I hunted around a bit but couldn't find anything other than "preventing partition separation". No "how to fix" it."
Sorry - I forgot about that. I need to update that info, or maybe just start a new post.
There are a couple of things I've heard of that can reduce or cure truss uplift AFTER the house is done.
First would be to increase attic ventilation. I read about a case once where a duplex was built using 56' (?) clear span trusses. The house supposedly had 3" of truss uplift the first winter.
When the truss manufacturer was called out, they found there was no attic ventilation AT ALL. The HO apparently sued the builder, who eventually installed soffit and ridge vents. The next winter the trusses moved less than an inch.
As I (think) I said in the truss uplift thread, I've never been in a house with truss uplift that had good attic ventilation. And I've never been in a house with working soffit and ridge vents that had truss uplift. So based on my experience, ventilation is the #1 cure.
The 2nd thing I've heard of is finding the screws/nails in the ceiling drywall nearest the affected walls, and driving them through. This gives the drywall more room to flex.
The only other solutions I've heard of involve crown molding attached to the ceiling so it can float up and down the wall. Seems to that would be fairly expensive.
There is one ofher thing which I think is often overlooked that may contribute to truss uplift - Lumber shrinkage in the floor system.
Assuming you have conventional 2X lumber for both the floor joists AND the interior beam, they will shrink some during the winter when the air is drier. I think that's sometimes a contributing factor, but the trusses are generally blamed.
I don't have any research to back me up on that one - It's just a theory.
Sometimes you're the bug and sometimes you're the windshield.
> The only other solutions I've heard of involve crown molding attached to the ceiling so it can float up and down the wall. Seems to that would be fairly expensive.
Another thing to do when you have central hallways is just to give them their own short ceiling joists supported by the walls, completely independent of the trusses. In ordinary rooms, you can hide the flexing over a wider span than you have available in a hallway.
-- J.S.
Dirishinme,
I don't believe they do help with truss lift, but they do hold the perpendicular partitions in place without nailing the trusses to the walls. If you nail them to the walls you're at risk of having problems with the bottom chords bowing up between the nail and the bearing points.
kcoyner
Okie, Ill ask the stupid question here.... Why does it matter what height the framed walls are when you are putting on the trusses? Is it a strength/weight issue? e.g.-less strength in a 10' wall compared to an 8' wall, and the truss being designed accordingly? or is it for cathedral ceilings/weird changes in the bottom board of the truss?(was that called bottom rung, or bottom??? I need to go back and look at the cheat sheet Boss showed in the first truss question)....
Alot of times on houses, you have different sized walls....knewalls, ballon walls standard walls, etc.Now when you say 8' wall, it's usually never 8'. It could be 8', 8'1-1/8", 8' 1-1/2", etc. Add in different ceiling heights and what not and it can get confusing if two different people are "figuring it differently...
I guess I am still confused... what does it matter if I make my walls 8' or 8'1-1/8", 8' 1-1/2", etc... the trusses should still fit on the same?!?!? unless we are talking that the roof height can change multiple times throughout that lower chord, then I could see your needing to know "hey, this wall is 8', this wall is 8'1-1/8", this wall is 8'1-1/2", then the last wall is back to 8' "...
am I barking up the wrong tree... am a bit confused...
Your not barking up the wrong tree Grouchie. Some times the walls vary by a couple of inches or a coupla feet or twenty feet.
blueJust because you can, doesn't mean you should!
Warning! Be cautious when taking any framing advice from me. There are some in here who think I'm a hackmeister...they might be right! Of course, they might be wrong too!
Grouchie,>>>>>> unless we are talking that the roof height can change multiple times throughout that lower chordYes. That's part of it. Another thing is, when alot of trusses are different and the HAP is different on them.
thanks for the replies.. pretty sure I have the concept now....
Grouchie, that's not a stupid question.
I need to know the height of the wall so I can tell the framers how long to cut the studs. Quite often, the upper trusses and roof lines will run from first floor plates to the ridge that is dictated by the upper roof system. For us to proceed with confidence, we need to know three key measurements: span, pitch and heel. Quite often, we are dealing with very a very large number of wall heigths and offsets. Each offset creates a new set of heels and wall height combination.
I've built houses with as many as 100 different trusses. Before I can proceed, I need to be absolutely, 100% confident of each wall height, heel, span, and pitch. That means I have to verify every component in the house before I can proceed.
I remember one particularly challenging house. The truss system was so interdependent upon each component that it took me a full 12 hours of onsite detective work to figure out the height of the walls. I know for a fact that the truss guys can include the necessary information very easily because each truss calculation would necessitate the need to generate a heel height, using some sort of assumed plate height. All I need to know is that assumed plate height. If you'll give me that, I'll build it correct.
Here's a picture of a complicated house that we framed that had a wide variety of plate heights.
Just because you can, doesn't mean you should!
Warning! Be cautious when taking any framing advice from me. There are some in here who think I'm a hackmeister...they might be right! Of course, they might be wrong too!
bearing pt. #b1 could deflect the truss if it's built wrong