I’m going to be putting up 16 fifteen foot trus joists today. I saw a note in the online manual about not using sawn lumber for the surrounding rim boards due to there possible shrinkage over time. I already have the lumber for the rim boards and had never heard this before … not even from my architect. Does anyone here with experience know whether or not it is OK to use lumber — I’m working with trusses that are 9 1/2 inches deep so I’m planning on using 2X10 — for the rim on both ends that the tji’s run in to? This is a ceiling on two supporting walls … one at each end .. one 2X8 and one 2X6.
I’m more interested in common practice in the field than I am in manufacturers suggestions.
Thanks!
Terry
Replies
"I'm more interested in common practice in the field than I am in manufacturers suggestions."
That makes no sense what you just said. It is common practice in the field to follow manufacturers suggestion when it comes to this.
It's not ok to use it. Your 2x10 could be 9-1/2" today and when it shrinks it could be 9-1/4". Follow the manual. Just get the rimboard your supposed to use and do the right job and you wont have any problems.
2 X 10s are 9 1/4" deep. I-joists are 9 1/2" deep. So the heights won't match up.
Since you asked about "standard practice" - I've never seen anyone use 2X lumber for rim boards.
I would also suggest using the rim board. If you have a problem with the I-joists, and call a factory rep out there, that gives them a pretty good reason NOT to give you any warranty service.
Thanks guys ...
There are many things that are done commonly in the field that a rep will never tell you about. I've recently called the permit specialists downtown who are responsible for passing permit applications and had them tell me to do something that I had never heard of. When I ask "will the inspector know about this enough not to balk at it?" The PS will say "everyone does it and it is generally recognized as OK despite it's not being written down anywhere."
The last time this happened to me was in my calling to ask about using 3X lumber for a heavy shear wall. I wondered if there was any chance I could use two 2X's nailed together. The answer was "yes ... just be sure to use the nail-spacing that is called out for the degree of sheer you are after. For instance ... the nailing in the field for an SW (shear wall) - 4 is 2" ... if you nail the two 2X's with that pattern it becomes usable as a solid 3X for shear purposes. That can bail you out in a pinch and it is NOT recorded in local code .. but USED IN THE FIELD!
That's what I was talking about.
Thanks again -
Terry
I'm with Boss on this - I've never seen TJI's with dimensional rimboards. They should be stock in that size and you can return the 2x10's. . . .
In a pinch (call the mfg on this), you may be able to use a another TJI as your rimboard.
Doing this may or may not be addressed in the TJI field guide - however, remember that the field guide is just that - a guide. The mfg can and does deviate from that guide because they can size components with the engineering to back it up. We mere mortals should refrain from deviating form the guide without mfg blessing.
If it were my house, I would want TrusJoist's LSL rimboards, which are available in depths to match all their I-joists. You can use ripped plywood in some cases, and I-joists themselves in others, but please don't use sawn lumber.
A typical SPF 2x10, by the time it reaches an 8% moisture content (equilibrium in a moderate climate) will have a depth of 9 inches.
What builder would want a 9-inch rim sitting around his perimeter, underneath all his bearing walls supporting floor and roof above, when his floorframe is a depth of 9.5"?
>> I'm going to be putting up 16 fifteen foot trus joists today. I saw a note in the online manual about not using sawn lumber for the surrounding rim boards due to there possible shrinkage over time. I already have the lumber for the rim boards and had never heard this before ... not even from my architect. Does anyone here with experience know whether or not it is OK to use lumber -- I'm working with trusses that are 9 1/2 inches deep so I'm planning on using 2X10 -- for the rim on both ends that the tji's run in to? This is a ceiling on two supporting walls ... one at each end .. one 2X8 and one 2X6. <<
Are you talking about I-joists or floor trusses? I'm guessing you mean TJIs (TrusJoist I-joists): http://www.trusjoist.com/PDFFiles/2025.pdf not floor trusses: http://www.chesterdawe.com/beavertruss.htm Suggestion: for the sake of future clarity, don't use the word truss the context of I-joists.
Anyway, normally I-joists are part of an engineered floor system that comes with a layout sheet that specifies engineered rim board - normally made by the same manufacture as the I-joists. Don't use dimensional lumber. Never seen it done, and wouldn't try it as I like passing inspections...
email from my architect today . . . should I fire him then?
It's not the material that's the issue-it's having the loads of the floors and
walls above not carried only by the floor joists-which are designed mostly for
strength in bending and not for strength in compression. That's why rim joists
and solid blocking under walls is necessary-it's not just to keep the floor
joists verticle-it's to help carry the load from above so the floor joists don't
crush. So having the tops of the rim joists flush with the tops of the floor
joists distributes the loads from above to both elements and not to the floor
joists alone. Using 2x instead of manufactured rims (versarim is a boise cascade
product) is fine as long as the material is kiln dried so it doesn't shrink and
is the same height as the joists (a tad higher is better than lower). If the rim
joists are below the floor joists than thin strips should be put on top to match
the height of the floor joists. This is not important on the far west wall-only
under the tower walls.Terry
Terry, I've seen that note too about not using sawn lumber. I find it interesting that they then tell you to use sawn squash blocks.
There is maybe a very good reason though. If you are supporting a bearing wall on the rim (most rims do support some sort of wall), then it might be important to use a rim that won't shrink. If you use sawn lumber, it will shrink at least 1/4". If it started out flush, then maybe the ends of the i joist might have an additional load applied and experience some crushing that could affect your end product. I suppose you could install squash blocks under each stud to combat that effect.
On the other hand, you still might be opeing yourself up if you had a warranty claim. The use of squash blocks would give you a great defense (they tell you to us them under point loads), but you might still have to fight to get a claim honored.
If warranties aren't high on your list, use your sawn and add a couple of squash blocks were necessary.
blue
Hey bedevil,
One side of this is supporting nothing .. it's supporting, I should say .. no walls above .. only a flat roof.
The OTHER side ... the other 'end' of the I-joists are on a heavy shear-wall and also have 3 floors above them. I'm nervous about that and will make very sure before proceeding that I do that end right.
You're right though ... it's bizarre that they warn not to use sawn lumber and, right next to that warning, show show and recommend 2X stalk for squash blocks and blocking of all sorts. Go figure.
thanks -
T.
>> You're right though ... it's bizarre that they warn not to use sawn lumber and, right next to that warning, show show and recommend 2X stalk for squash blocks and blocking of all sorts. Go figure. <<
That is because dimentional lumber tends to shrink in width and thickness - not in length. Also, I think you may find that the recommended squash blocks are an 1/8" or so taller than the actual I joist...
As far as what your architect is recommending, as far as I know, it's highly unusual. He is the one with the fancy degree though...
I agree, the fact that the grain is running vertically in using squash blocks is the difference.
Also, if you read the instructions included with the joists it says to cut your squash blocks 1/16" taller than your joist depth to compensate for any shrinkage that may occur.
EDIT: Is there an echo in here? I'll be standing back here repeating everything you say, ok?
Edited 11/14/2005 9:38 pm ET by dieselpig
Read closely what Matt wrote.Squash blocks can be cut from dimensional lumber because they are stood ON END. Dimensional lumber is pretty stable in the end-grain aspect.With engineered products, you simply don't screw around with the installation. Your architect should know better.Install the product in accordance with the manufacturer's installation instructions.Usually for rim you can use their proprietary rim, another type of engineered beam (LVL, etc), or doubled up 3/4" ply. Depends, so read and heed.Why the resistance?
He says in his first post that he is more interested in something like "common practice" than what the engineered wood product manufacturer specifies.
Who knows why he's down on TrusJoistMacMillan, but he seems to have thought there are pearls of wisdom to be mined from jackleg framers who like to throw away the instructions and wing it.
Or maybe he's getting this from the architect, who sounds like a moron, with his "OK if it's kiln-dried" remark.
Gene: It's funny how we all trade off the PC hat. Your last remark was pretty much what my last remark was above, just worded a little differently :-)
hey 'stinger'
I already explained what I meant by "I'm interested in what it commonly practiced..."
Manufacturers reps are always on the lookout for what they can sell you. Sometimes, materials can be substituted for what they are offering at no expense to the integrity of the structure. What -- You haven't noticed this? LOL
Despite your (empty) post I got, as I've come to expect, some completely excellent feedback from others here. I'm designing my approach on paper now using what I got here and what I'm looking at on the Louisiana Pacific I-joist site.
Feeling much better about moving into installation of these tji's now.
Thanks again to all who offered assistance.
Terry
Just a quick thought new,
An I joist with 1/2" ply/osb nailed on the side can be used for a rim board ran parallel with the joists(it probably shows this on the supplied print). So since you only need about 50' worth of rimboard for the rest, instead of waiting for a couple manufactured rimboards to be delivered, just fingersliding a couple of long 2x rips is the way I would go to save time. I personally have never done it but I would agree with those who say its ok to do, as long as you do leave them a lil high for shrinkage/compression. If you choose to start layout and wait for the new rim to be delivered, just remember that its 1 1/8" thick and not 1 1/2" like regular 2x is. Just my $.02.
Matt
Matt -- thanks for your input on this.
I'm going to over-build it with on-end 2X4 squash-blocks all along and also use web stiffening on every other or so for the full run. I'll make my own rims by ripping 3/4 ply. I've gotten nervous about this whole thing since I started reading the online manual ... which was never supplied me when I bought the joists ... so, again, I'm going to over do it some so I'll feel fine in the long run about this wall. It's going to have three full stories resting on it above ... it's gotta be BEEFY!
btw -- Happy Birthday! You're exactly my son's age and one week away from his birthday.
Terry
All the jobs I've done with TJs have squash blocks and/or web stiffeners made of LSL. The manuf. inspector rejects dimension lumber used for this purpose - even when it is used with end-grain parallel to load. I guess commercial guys get our hands held...Lignum est bonum.
The manuf. inspector rejects dimension lumber used for this purpose - even when it is used with end-grain parallel to load...
that's what I've been talking about. The manufacturers want you to buy ONLY their stuff. Baloney. On end 2X squash-blocks are the norm. Not 'manufacturer provided specialty items'. Man o man. Screw 'em if they can't play fair.
Why not just avoid the whole issue, and use 2x10s? If you think the I-joist maker is trying to shaft you, just go sawn lumber all the way.
Terry I'm not sure how things work in your jurisdiction, but here what you're proposing wouldn't fly for load bearing structures. Like trusses, TJs are an engineered system that exists outwith the limits of the building code. Inspectors allow the use of such systems because they are under an engineer's control. The design and spec sheet for any TJs and/or trusses has to be supplied along with a permit application, and all work must be performed in accordance with manufacturer's specs. There's nothing unreasonable about that - the manuf will stand by the product and their structural claims for it, provided installers use it as it was designed.
Now whether or not you think LSL squash blocks are a scam, they are part of the manufacturer's engineered system. Obviously you like the TJ product enough to want to use them, but you're balking at keeping the system intact.
Now of course there is another system available to you without proprietary parts and specs. Solid lumber joists are covered by the building code and you can use all the 2x squash blocks you want. But mix and match isn't a good idea at all. A plywood rim board won't be anywhere near as strong as 1.25" LSL. Lignum est bonum.
sl,
I hear what you are saying, it rings true, and I take it to heart.
I am not compromising anything or taking any chances. I'll use upright squash blocks out of 2X, but that is shown as sound approach on all the manufactured joist manual sites. If I use the plywood rims it will not be for load strength but for fire blocking and web strengthening and joist positioning/setting. I've altered my intended approach even despite what my architect, who has been a builder/architect working steadily for 30 yrs in the field and who teaches on the side, has said is ok. So ... it's not like I'm not listening here.
Thanks for taking the time -
Terry
Has this job been engineered, or are you just winging it?
Why would you think you need squash blocks at each joist end up against the rim? Squash blocks are typically seen only at concentrated load points.
Besides, I recall this job as using 9.5" I-joists, and you've no way to get a matching rim height in sawn lumber unless you rip 2x12s to 9.5! What's this all about, anyway?
Why the big aversion to using LSL rimboards? If you think you are saving by using a sawn lumber rim, but then are expending labor to cut (and lengths must be precise), fit, and fix squash blocks, you'll probably spend more $ than just slapping in the LSL rim.
If you've a beef with the cost of engineered lumber, and think they are stuffing it to you with their "systems" approach, making you use their rim with their joists, why are you using I-joists anyway?
I am getting the feeling this thread is bogus, a hoax, begun and kept going to just rile us up for entertainment's sake.
Stinger,
From what I understand he didnt get rimboard shipped with the I joists and he was just looking for a way to do it with regular 2x material.
By the way newbuilder, its really not a big deal, run your box, cut some squash blocks, nail 'em into the box and joist and be done with it. Boom, bang, done in an hour and you can have complete confidence in it holding all three stories.
Thanks for the Happy Birthday!
Matt
By the way newbuilder, its really not a big deal, run your box, cut some squash blocks, nail 'em into the box and joist and be done with it. Boom, bang, done in an hour and you can have complete confidence in it holding all three stories.
That's just about exactly what I'm doin. It's always a *little* more complicated than it sounds -- for me at least -- but the picture you draw here is really what I'm doin now. I did some checking around and had a long ph. conversation with my architect today ... he pretty much said what you did here. By tomorrow night I should have the joists all up and I HOPE to actually have the t&g on ... tho that may be a little ambitious. We'll see!
thanks for the vote of confidence!
T
hey, new, welcome aboard.. as you have already seen , there are a thousand ways to skin a cat.. and a few of them are even good ideas..
your architect seems like a pretty reasonable fellow and hasn't steered you wrong yet..
just be careful of the jargon, the mis-communication is what can kill you.. or the question you didn't ask
manufactured vs. solid.. they can be mixed..and all of the installation manuals i've seen support and encourage their mix...but you do have to read the fine print.
thes lumber companies are trying to make a user-friendly product with real field-condition installation
the only thing i saw that made me sit up and take notice was one of the posters talking about commercial installations... in that case.. nobody is going to stick their neck out.. what ever was spec'd is what is going to be approved unless someone higher up signs off
the code is different for one & two family dwellings vs. larger buildings..
anyways.... ain't it grand ?
ps.... MONGO... where the hell were you at Cal's ?.. talk about falling off the edge of the earth ....
Mike Smith Rhode Island : Design / Build / Repair / Restore
Mike, Taunton doesn't pay for enough bandwidth for me to tell you how fun my life has been...<g>
as long as you're having a good time.....
life does seem to have accelerated for some reason... wow ! these days are racing by..
hope all your skys are friendlyMike Smith Rhode Island : Design / Build / Repair / Restore
Hey, the kids are healthy, Rebecca still loves me...what more could a guy ask for?"Work" work is work. Lots of stuff going on in the air and on the ground. Court hearings have been pretty much a black hole for me time-wise."Home" work is just dandy.Next time you find yourself down my end of I-95, ring me up. The beer fridge is always full and the pretzels are never stale.
the only thing i saw that made me sit up and take notice was one of the posters talking about commercial installations... in that case.. nobody is going to stick their neck out.. what ever was spec'd is what is going to be approved unless someone higher up signs off
interestingly enough .. this is EXACTLY what my architect said when i informed him of some of the response here. ((I get a sneaky feeling he *might* even read the board ... hi Tom .. )) That if you're working for someone else, and they're asking you to do this and that in just this way .. AND they're paying for it! .. then you go buy the manufactured rim joist and lay it in!
the code is different for one & two family dwellings vs. larger buildings...
I am building this an an "accessory dwelling" to my own house ... though it stands completely separately on it's own 20X30 ft. pad, and will stand over half again as high as the house and with more sq. footage.
just be careful of the jargon, the mis-communication is what can kill you.. or the question you didn't ask
This is so true ... and with my situation .. working completely alone day after day .. it applies not only to those times that I communicate with my architect, or friends just discussing the project .. or other builders .. but to my own communications with myself over what's important to take care of next .. what not to forget first thing tomorrow .. what to be SURE to do here before beginning there .. etc. Things are constantly occuring to me that I sorta 'gasp' and think .. my god .. what if I hadn't realized that i need to do that first or I'll run into trouble later. One has to proceed with EXTREME caution when building completely alone. (boards like this can be really wonderful for a lone builder.)
anyways.... ain't it grand ?
Yes YEs YES! ... it is, indeed, absoeffinglutely GRAND!!!
In many many ways .. there is NOTHING 'better' than building -
T.
I am getting the feeling this thread is bogus, a hoax, begun and kept going to just rile us up for entertainment's sake...
Jeeze man ... you're nutty!
I just got in from working on this project and it's after midnight my time. It aint no 'hoax' -- I'll be on it for the next year at LEAST. I'm essentially building an entire house completely on my own. And I'm not even a 'builder' ... or never been a pro at least. The only thing I hired out was the foundation .. the rest is completely mine. I'm doin it cuz I think it can be done and I enjoy the process ... and .. by the way .. I think most of your questions were all ready answered in the thread.
lighten up!
Terry
I am getting the feeling this thread is bogus, a hoax, begun and kept going to just rile us up for entertainment's sake.
I don't think this discussion is a hoax at all. In fact, there's an important lesson/point in here. All too often, carpenters fall victim to doing things that might not make sense, because they don't understand that they have options. If you took the advice of some in here, you would be led to believe that it's impossible to use anything other than a manufactured rimjoist to meet code, or to build a quality product. Instead of blindly following that advice, I've always tried to understand the "whys" of what we are building.
The rimjoist provides protection against crushing the I joists end. That crushproofing can be accomplished in many different ways and occasionally it makes sense.
What if this poster had just done a major tearing out of a framed deck and had 400' of dried knot free pristine douglas fir joists laying around. Should he use this for firewood and order up 400' of expensive manufactured rimjoist? I say no, but it's important for him to understand how to protect the rest of the installation.
Myself, I wouldn't rip plywood. I'd shim the 2x10 with a piece of 7/16" osb and add enough squash blocks to avoid crushing the ends of the i-joist. I think in 50 years, my installation would be as good as a rimjoist.
blue
there's an important lesson/point in here. All too often, carpenters fall victim to doing things that might not make sense, because they don't understand that they have options. If you took the advice of some in here, you would be led to believe that it's impossible to use anything other than a manufactured rimjoist to meet code, or to build a quality product. Instead of blindly following that advice, I've always tried to understand the "whys" of what we are building....
bedevil,
You speak pure gospel; The gospel of building. We're trying to put up a cohesive, sensible structure that's safe, solid and uniformely integrous. Of COURSE there are a myriad of possible approaches to any given situational need. How could it be otherwise? Even FineHomebuilding is constantly full of "try this" and "here's another way to..." And that's a GREAT part of the fun of it .. isn't it!?
I went with 3/4 ply on end but with a solid squash-block at each and every joist-end. According to my architect that's 'over'-doing it .. which I'm happy to do. I went with the ply because I'm really relying on the s-blocks and because it gives me an extra 3/4 inch of space on the surface of the top plate that's open. I've got FIVE (count 'em) upright 6X6 posts underneith this that need to be joined to the posts above them by Simpson HD10A's. This means drilling up throught the top-plates and reaching up through, between the joists, with a long 7/8" threaded bolt ... so any 'extra' space -- side to side -- on that top-plate that holds the joists is a help.
Anyway .. thanks for the post. All I really needed to say to it was 'amen'.
Terry