What is the best way to line them up straight?
1) Pull a string line down one side of building and use it to line up the plumb cut?
2) set both ends of the building and pull a line at the peak?
3) Some other way??
I’m looking at trussing my garage roof. Nothing fancy, just a square building approx 28′ x 28′.No valleys, intersections, or adjoining walls.
These will be a regular gable truss, 4/12 pitch with an 8″ overhang.
So how would you set them?
Thanks, Bill
Replies
If the wall is straight (or straight enough) I mark the bottom chord of the trusses while they sit on the stack. You can extend the marks up the sides of the chord later if you need to. Lookout for variations in the trusses (ususally not much if any) and not to swap them end for end during the install.
I string the peak. keep all the "rights" on one side and all the "lefts" on the other. I have at times found that they have not been symmetrical
wyatt
I did same as John, mark em while stacked and eyeball the mark to the top plate After the wall is straigtend and braced.
We used to block and string the walls, but after awhile I found eyeballin to be faster and more betterer. One guy sights, another pulls or pushes on the brace and nails off to the deck.
Spheramid Enterprises Architectural Woodworks
"Welcome to Poo-ville, can I have your socks?
Seriously Folks, I need a home for 3 lovers of your life.
My advice to a guy like yourself, who doesn't do it all the time, would be to set the gables first, then string the line. Also, I agree with the others that you shouldn't spin the trusses. They do indeed sometimes have a front and back. Keep them all the same and you will minimize problems but realistically, the biggest "problem" is only a two minute fix on a set of trusses like yours.
I'd fasten the gable trusses onto the end walls before I raised them. Gables that small only need two studs on the flat to hold them, if you securely figure a way to fasten the bottom chord.
Bob's next test date: 12/10/07
Wow, that was quick!
great advice from all, especially not flipping them end to end ( I never would have thought about that ).
I'll be shore to identify right side / left side when they are delivered.
This is an existing building ( flat roof ) and based on what I already know I would'nt trust it for straight or square.
It sounds like I should set the ends and pull a line on the plum cut ( Fascia ) on one side as opposed to the peak, less chance of buggering up the string line that way.
Does any one ever find the rafter tails need to be trimmed to keep the fascia straight?
Thanks again for the help,
Bill
the truss guy i use leaves all the tails long,so once they are up,stringline them and cut so the fascia runs dead straight.if a man speaks in the forest,and there's not a woman to hear him,is he still wrong?
It sounds like you are getting ready to give yourself headaches. The ends of those factory plumb cuts can vary quite a bit. You are probably thinking of them all perfectly lined up to create a perfect flat plane so your fascia can nail on easily. Its seems so simple and logical. I think of the plane of the roof first, starting at the top of the fascia line. The difference is that I install my fascia first and work the roof plane to it. Most guys think of the HAP line as their governor. That lines corresponds with the outside wall line, so it is instinctively a correct place to start but there are some tricks to making that work out. Nothing that common sense won't dictate but often the common sense doesn't kick in till after all the trusses are standing and a problem rears it's ugly head. You'll be fine with any method but it's probably a good idea to talk the entire process through, as you have started to do. Bob's next test date: 12/10/07
If you're going to have to trim the rafter tails I've found it easier to ignore them. Usually trimming the tails is due to a crooked setting of the trusses.
Build a ladder from 2x subfacia and a 2x that will nail to the wall. Make the 2x supports a little longer than what the tail is set at and and put it in place. The ladder can be made on the ground and lifted into place. The attached pic might help. This is counting on the wall to be straight enough. Also remember that if gutters will be installed nearly all straightness or non straightness will be moot. I focus more on a flat soffit than a straight facia.
I've never found cutting tails in place fun at all (feel like I'm doing more hamr than help) and I try to avoid it all costs.
Do you know how straight your wall is?
I hate cutting them in place too and avoid it at all costs. Bob's next test date: 12/10/07
Been wanting to tell you that I've found your thread on panelized framing pretty dang interesting. I know one framing crew with a boom truck but their heads are too thick to learn anything new. After reading your thread I now know how inefficient they really are.
That's funny.
Thanks for mentioning the thread. Without feedback, the guys posting pics sometimes don't think anyones reading. It takes abit of time to do those photo threads and once I get the idea that no one cares, I lose interest myself. After all, I've already done the techniques....I'm just posting for other's benefits.
I started another on dormer framing on the tables. Enjoy! Bob's next test date: 12/10/07
Hand't thought about a level cut always a plumb cut. But how much tail is there to nail with the level cut? Do you still have to make a plumb cut to get enough to nail to or are the tails attached at all to the lookouts or subfacia? I'm sure you got a close up detail pic of that.
>That's funny.<
Now what's funny is that I'm thinking of CMUs and writing CBUs in previous posts. Freudian slip of Bombs Vs Blocks?
There isn't enough meat on low slopes to effectively hold the rack up. Thats why we added the extra member on the flat. It's a waste of lumber but aids us in our installation time. Its one of the few areas that you will ever see me wasting a stick of lumber. For most of that overhang system, we probably were using every chunk of lumber cut offs that were lying around. It's very fast and easy to just grab stuff and shoot it with the nail guns.
We developed the level cut strategy on the steeper pitched roofs. If you project the top of the level cut out to the outside of the fascia, and you have it backed up with a subfascia, the rafter will yield 2 3/8" of meat to toenail through. Our system plains the top of the rafter in to the outside of the subfascia. That yields 1 1/2" of meat to toenail through or nail through the top.
I'm sure everyone would think that this is not enough but you have to look at the entire system when it is completly nailed up. The nailing alone through the plywood would hold the overhang up forever. The nailing that we do before the plywood is laid is enough for me to walk on it.
There have been certain situations come up (they are rare) that I decided that I wanted some extra holding power. In those cases, I add blocks on 4 or 6' centers, which substantially increases the overall holding power. If I had any worries about the structural integrity of the installation, I'd use the same system and add the extra holders. There are several ways and I've done all of them. One of the easiest is to add some steel banding iron onto the subfascia and wrap it up onto the top of the truss.
So, if anyone wants more beef than our present system, I have plenty of options and none of them would alter our methods to any great degree. We just haven't ever seen the need. When the situation arises, we proactively deal with it. Bob's next test date: 12/10/07
Just so ya know, I've been reading both of them, just not had anything to add. Great job posting all that, it does get long at the wheel posting the pics. Thanks.Spheramid Enterprises Architectural Woodworks
"Welcome to Poo-ville, can I have your socks?Seriously Folks, I need a home for 3 lovers of your life.
Thanks for mentioning it.
I just figured out how to add the pictures to load. I could never get it to work because I was using Firefox. I hope I'm not driving the dialuppers off the thread(s). Bob's next test date: 12/10/07
1 more thing. if you're going to be ripping the roof off to set the trusses be sure to brace the walls during the truss setting. You might be able to correct any straightness issues at that point as well.
Also find BossHogs thread on CLB that will be spec.ed in the paperwork that comes with the trusses. Found it: Truss Web CLBs - The Basics
Jim,
It sounds like you are getting ready to give yourself headaches.
I tend to do that to myself. In a effort to "understand" I over think stuff.
The ends of those factory plumb cuts can vary quite a bit. You are probably thinking of them all perfectly lined up to create a perfect flat plane so your fascia can nail on easily. Its seems so simple and logical.
That is exactly what I am thinking. So would you string line the top of the fascia, or stick with the peak?
John,
Build a ladder from 2x subfacia and a 2x that will nail to the wall. Make the 2x supports a little longer than what the tail is set at and and put it in place. The ladder can be made on the ground and lifted into place. The attached pic might help. This is counting on the wall to be straight enough. Also remember that if gutters will be installed nearly all straightness or non straightness will be moot. I focus more on a flat soffit than a straight facia.
Interesting idea!!
So the Soffit ladder is installed first, and it permanent? And yes their will be gutters.
It's a concrete block building so the wall is as straight as it's ever going to get. I'm lookin to build over the existing flat roof, so not a lot of demo.
Thanks agian,
I'll check back tomorrow,
Bill
John's system is how I was taught, although we always finished all of the soffit system. The key to John's system is the 1/4" gap that is left between the sub fascia and the truss. You might be surprised to find out that it varys between tight, too tight and too loose when it's done. He holds everything up by attaching the trusses to the lookout blocks.
Our system has morphed quite a bit but it wouldn't be appropriate to go into it with you. Lets just say that your safest method for getting the easiest blend of the trusses is to use the peak as your governor. The second safest method is John's. His might cause you a little grief setting the trusses but nothing too complicated that a couple strong boys can't figure out. Bob's next test date: 12/10/07
>He holds everything up by attaching the trusses to the lookout blocks. <
Actually I hadn't thought of this. The 2x along the wall is nailed through the sheathing/R-board but in the OPs case of CBUs it's probably a better idea by dropping another 2x down from the rafter to catch the horiz 2x along the wall. No need to attach to the CBUs then.
Like Jim said, the ladder goes up last and it's permanent. There is no direct nailing between the subfacia and the rafter/truss. Going against CMUs I'd use PT 2x on the wall and if facia rot is a concern I'd use PT for the subfacia as well so if the facia ever rots and you get behind the curve on theoritically the subfacia and tails stay intact. Using todays PT is tough on fastnerns so be sure to chose the right ones (stainless, Triple dip galv etc.)
I have a diff opinion than Jims on the truss alignement though, and wold mark the bottom of the chord on an edge/line you trust and and see easily. CMUs do fall apart from side loads so if you're not going to brace be sure to treat them nicely.
Build over existing roof... Going to build a knee wall on top of the original to set the new roof? Maybe straighten things out there.
Edited 4/13/2008 7:02 pm ET by john7g
Oops...nope...I would put the ladder up first. Bob's next test date: 12/10/07
So you set the ladder and use it to guide the trusses? But youre' saying your tails vary to much for that. Got any pics of this to add to the panelized thread? Could probably nail on the soffit ply as well along with any vents if you set the lader 1st.
With the trusses I get from a local supplier, if the vertical cut for the tail has been made, it's close enough to for me not to worry about.
We actually use level cuts now, especially on the higher pitched 12" soffit systems. That usually gives us enough meat to spike though catching the subfascia, then we also nail through the roof sheathing 4" oc. It's been plenty strong enough to carry full length iced up gutters (mine held up fine many times) but if there is some compelling reason for more holding power, we add some simpson stuff or metal wall ties in a way that hold it all up some more.
View Image
This shows a wider rack built for a lower pitched roof. He also had a 2x6 subfascia specified. It was all going to be wrapped in aluminum. We decided to add a level linial member to provide greater toenailing capability when we level cut the trusses.
Heres a shot of that same rack with the sheathing installed.
View Image
As you can see, we've cut the tails level at the 16" past the wall mark. That automatically creates a level overhang. As we set the trusses, we pull the overhang up tight and put a couple nails into it.
Most of the time, we've already finished the entire overhang before we start the trusses. This one was an exception. We mostl likely leaned over and sighted the overhang and could see that it was straight. We'll piece that small section in off the machine, or hang over, before we set the next section of trusses.
There are lots of reasons why I prefer the level cut method.
Bob's next test date: 12/10/07
Hi John, sorry for the late reply. I've been working 12 days.
you said:
Like Jim said, the ladder goes up first and it's permanent. There is no direct nailing between the subfacia and the rafter/truss.
Dumb question time,
So how do we go about holding up the outside edge of the ladder if it's not nailed to the truss?
Bill
Nail the lookouts (the 2x that span between the wall 2x and the subfacia 2x) into the side of the tail and the 2x that runs the length of to the wall into the studs. Usually nail the 2x along the wall first then level the soffit ladder so you can nail into the side of the tail. Good to have 2 people to do this. It's real quick so don't promise too much beer for the labor.
I attached a pic to help.
12 days in a row? Is that legal?
Edit to add: Looking at the quote I wrote; it's incorrect. The ladder goes up after the trusses/rafters.
Edited 4/19/2008 7:42 pm ET by john7g
Thanks John,
The picture cleared things up perfectly. The term "Lookout" was messing me up.
12 hour days, yeah I work in the defense industry. We are VERY busy. The up side is all the overtime pays for these projects I get my self into.
Bill
Temp braces. We usually put three on long walls, two on shorter wall and one on short walls. Sometimes, you don't need any, depending on the size and congifuration of the rack. Bob's next test date: 12/10/07
Low sloped trusses with the span he's talking about (28' - 4/12) won't have any CLBs.
Nobody listens to me until I fart
but won't here be something to prevent them from dominoing spec.ed where the CLB would be spec.ed? I use CLB (inaccurately) to refer to the bracing needed on trusses.
did you fart?
CLBs and erection bracing often get confused, even though they're completely different things. He will likely get some erection bracing instructions in the packet of paperwork that's delivered with the trusses.
I Fart In Your General Direction [Monty Python]
You guys all have your way, now I will explain the way we(framing crew) do it.
We sheath the gable and install the ladders on the gable. Then we (real important) hire a boom truck to swing them in place. No more pushing them by hand, good way to injure yourself.
Then we make sure the walls are straight, use your good eye. Then we put hte trusses up, lineing them up with the top plate. With appologies to truss man., the tails are all over the place when it comes to length.
Once the trusses are up we measure out from wall to desired length on each gable. String a chalk line, snap then with a block with proper pitch, we mark each tail. This is done from on top. Then we cut the tails, useing a worm drive here is easiest. then install the subfacia.
With all due respects to Jim, I find your method very timeconsuming.
"With all due respects to Jim, I find your method very timeconsuming."
I agree that it's debatable. It really depends upon what the expectations are at the end of the game.
For instance, if all we had to do is install a subfasica and walk away, we might consider your system. I've done that enough times in my days to know exactly how to do it. I just don't like to do it. I hate the bending part: bending over and marking, bending over and nailing etc. I also hate stringing the line. I hate the entire process. But, I've done it many times.
But....if there is anything more than the subfascia required to complete the job, then I know for a fact that our system is substantially faster. I rarely make any decision that I know will take more time. I've done everything five or ten differnt ways...maybe twenty! Bob's next test date: 12/10/07
1. Measure in one inch from outside bearing wall top plate at each end.
2. Snap line on top plate.
3. Measure 9" in from end plumb cut on each truss and make mark.
4. Set truss and align marks on trusses with snapped line.
5. After all trusses are set, inspect opposite side plumb cuts for alignment.
6. If necessary, snap line and trim tails.
This actually works remarkably well. Th ground man roping the trusses marks each truss in a moment during picking, either with a tape or a wood block.
The benefit to this is that you only ever have to cut one side of the tails, if at all.
It also eliminates the tail setting to a string line nightmare.
carpenter in transition
Edited 4/14/2008 12:42 am ET by timkline
Gentlemen,
Thank you all for sharing your techniques and ideas . This discussion has cleared up a lot of questions for me
Jim,
Lets just say that your safest method for getting the easiest blend of the trusses is to use the peak as your governor.
It looks like this will be the best system for me. I have some carpentry skills but I'm no pro, simple and safe is good!
Oh and the pictures are great!
John7g
I have a diff opinion than Jims on the truss alignement though, and wold mark the bottom of the chord on an edge/line you trust and and see easily. CMUs do fall apart from side loads so if you're not going to brace be sure to treat them nicely. Build over existing roof... Going to build a knee wall on top of the original to set the new roof? Maybe straighten things out there.
Yes I will be building a knee wall roughly 18" high to clear the existing roof. I plan to fill the top 2 courses of block with concrete and bolt down a " top plate". This should keep the block from getting loose. Then build the knee wall on that.
I really like the marking bottom cord idea, maybe I'll do that along with Jim's suggestion of pull a line at the peak. A little extra time and effort is fine with me
timkline
1. Measure in one inch from outside bearing wall top plate at each end.
2. Snap line on top plate.
3. Measure 9" in from end plumb cut on each truss and make mark.
4. Set truss and align marks on trusses with snapped line.
5. After all trusses are set, inspect opposite side plumb cuts for alignment.
6. If necessary, snap line and trim tails.
It looks like you and john are pretty much on the same page. I was actually thinking about snapping a line on the top plate, nice to know that works
Thanks for all the help!!!
Bill
Tim, I really like your idea....but there is a flaw in it. With a little tweaking, it is a great idea especially for less experienced framers.The problem I have is that you are putting all your faith that the manufacturers have created the entire truss using the tail that you choose as their datum point. That's a huge leap of faith. I've known truss tails to wander as much as 1 1/2"! The solution is easy. Snap your line and that becomes your governor. A simple calculation will tell you what the theoretical height at this point should be. We'll call this the HAPCL (height above plate control line). Then, mark a square line on each truss at exactly the height that you've figured. The pictures show a red line that would become your control line. You could create a small pattern with a piece of plywood to mark that exact height every time, or use your "speedier square", otherwise known as framing square. Or, you could locate this point by measuring the exact point while hooking on the peak. This would effectively make the peak the governor, instead of your tail ends. Bob's next test date: 12/10/07
jim,
this is a good point, particularly in the case of the steep pitched truss with a larger overhang as shown in your photo.
the HAP point is well made. we often use the same homemade plywood "speed square" you mentioned to be as accurate as possible.
carpenter in transition
I know this seems counterintuitive, but we've always had a harder time getting the low pitched roofs to plane. Maybe someone can explain the math to me. Frank and I have talked about but I still don't understand it. Bob's next test date: 12/10/07