Mixing lumber with i-joist construction
I’ve been hit a couple of times here at mentioning mixing the use of standard 2X lumber for rim board construction with tji’s. Though there have been some here who have agreed with me that this is really not such a no no.
I don’t claim in any way to have anywhere near the experience and background of MOST of you others here. But I’m involved in a large building project that I’ve taken on more or less for the great fun of it, and some things I’ve done a little differently than the book.
Since the discussions surrounding mixing these building materials has always come out of other discussions, and therefore never been put on the table and discussed head on, I wanted to get some direct feedback on it. What is the big danger? I first found myself building my own rims out of 2X lumber when I found out the insane price of the rims that the i-joist manufacturers wanted to charge. (I’ve since been informed of the LVL that’s available but simply hadn’t heard of it before yesterday). I thought it then suddenly made sense to me why they urge us not to use anything but what they have to sell.
So I guess my question is, on outside walls .. where the floor stops and there is no ‘beyond’ that point .. why is it so damn wrong to use a rim made of lumber. I’ve been constructing sort of ‘headers’ to go on my outside walls: 2 2X10’s on edge with periodic 3X material inside to keep the 10’s exactly 2 1/2″ apart thereby creating a long ‘header’ that is exactly 5 1/2″ wide and 9 1/2 inches tall since I run a quarter inch ply ‘bed’ across the top for the subfloor to sit on. This does not even come into contact with any tji’s and it is strong enough to support some heavy walls that I’m using above. The only thing I’d really have a question about is that I also used, this time, 2X10’s on edge to ‘meet’ the tji ends at both opposite walls, nailing through them into the flanges. Here .. I could see how shrinkage could be a problem… but even so not necessarily.
But overall it seems to me that an eighth inch shrinkage here and there … why such a problem? .. we mix and match shrinkage prone and non shrinkable materials here and there all the time in building.
Any thoughts?
thanks –
T.
Replies
I agree! I don't see that shrinkage or differing dimensions are deal busters. I don't like sitting my outside walls on glorified OSB . I also think that the makers of this system would like to coerse us into using their product with warranty issues ect. Somtimes you have to take the bull by the tail and face the situation.
The way it was explained to me by the manufacturer, is that the rim acts as a header to prevent the weight above from crushing the I-joists.
I-Joists aren't that great when point loads are applied to them, the weight will cause the OSB to split the top and bottom flanges like a knife. Making all the crushed joists useless. Dimensional rim will shrink putting any load directly on the joists.
I don't know about you, but doing something that the manufacturer says is wrong and will void any and all guarantees is not something I look forward to doing. It's just not worth the risks involved in a failure of a floor system.
As for the costs of the rim joists, I have to pay for it and so does everyone else here to make sure that they are putting together a quality product. Saying it's too expensive is not a good enough reason for me to hope a floor holds up for a lifetime and more.
The manufacturer has run the numbers and engineered a system that is designed to work. Taking away pieces of that system may result in a failure, over what a few bucks? Not even close to worth the risk.
By leaving out pieces you are increasing your liability to that project, it fails and your on the hook now. Who knows it may never fail, I don't like to roll the dice to find out method. I stick with what the manufacturer says will work.
Can't you hear the violin playing your song.
I must say I agree completely that IF I were working for others I would build their projects such that any warrantees(sp) were good for the duration. But, as stated above, this job is a house extension of my own, and your imagined scenario does not actually apply here as my rims are not holding the weight anywhere near the i-joists (see original post). So ... I do employ suash-blocks ... 2X's on end ... to hold the weight. They are nearly completely impossible to 'crush'. But to build the outer box which contains the i-joists out of non-manufacturers material should not affect the joists themselves. Especially with squash-blocks supporting the weight off of the joists.
Thats how I see it at least ... but i'm here to hear how others do.
thanks -
T
Imagined scenario? This is real life man, the manufacturer says not to do it.
Good you added lumber to lumber to lumber, how much is that costing you? Your time and extra materials cost something right? Why not use what they say will work.
It is actually very quick and easy to put the rim up and put a joist against it. I use a joist as well on all outside parrallel walls. Makes the rim stay straighter and gives more bearing to the wall above.
If you are using 2x10 for rim it will shrink, then making it easier for your joists to roll. The rim toenailed to the plates also helps prevent that. Probably won't crush your frankenstein floor joists though.Can't you hear the violin playing your song.
My time is my own and I really enjoy the work so there's no loss there. Even with the added materials it's far cheaper than a Louisianna Pacific manufactured rim.
But I hear ya and am not really arguing ... if I had it to do over again I'd think more seriously about doing it the way you are describing. As stated earlier, I had not heard of the lvl's available at the yard (and not through the manufacturer) which are considerably less expensive than the joist-makers rims. Cost is a major consideration to me .. one of the reasons why all the work on this project is being done only by me solo.
Now I'm pretty much set ... but I'm going to insert more squash blocks in the middle of that header so that even if the 2X's shrink down some the blocks will support the wall at greater than joist heighth.
A suitable Frankenrim to match my Frankenjoists!
thanks -
T.
If cost was such a big factor you should have looked into floor trusses. Around here they are usually cheaper and easier to install. No cutting and the only measuring you have to do is layout.
To late now but something to think about in the future.
Can't you hear the violin playing your song.
I don't even know what a 'floor truss' is. I've been completely at the mercy of my architect on this as I'm not an experienced builder and I drew up the plans, gave them to him and he drew in everything necessary to bring them to code and he got them through downtown for me. He's the one who put down i-joists ... though he called for 9 1/2 X 1 1/2 ... a narrower flange. It was an engineer on the phone from LP who recommended their 210 series w 2 1/2" flange. Anyway ... I'm enough of a neophyte that, at this point at least, I gotta go with what those more in the know recommend. In most cases at least. And I'll say just once more ... it's my architect .. an experienced builder himself of many years .. who said it was ok to go with lumber on the rims. Whaddaya gonna do!
T.
Penny wise, pound folish. Like you I was very concerned by the bigger than planned cost of my remodel that I was very interested in any kind of savings. Kinda ended up with tunnel vision, lost sight of the big picture.
My remodel included a pop-up ceiling over the kitchen. One long side and the 2 ends are LVL's. The other long side, which isn't really bearing any weight, was spec'd by the engineer as a 4x12. The Arch. didn't question it; the GC didn't question it; I didn't question it. The results suck. The 4x12 moved enough as it dried to cause the ceiling to drop almost 2" over the 30" from the wall to the beam, and it was installed dead level with massive overkill on the fasteners (this is CA afterall).
So, yea, cleaver solution but the savings are such a small percentage of the overall cost vs. the potenial for serious aesthetic and/or structural issues that it's hard to justify. Ain't hindsight great!
Why did you even bother with manufactured joists in the first place?
While you state your reasoning that it is your own structure so your labor-intensive hacking is forgiveable, bear in mind that, in the long term, when your taking your dirt nap, some future owner of your crib may very well have to deal with what you have created.
There are several problems with using solid lumber as a rim joist.
First, the manufacturers recommend against it, so it would be a violation of the advice of the people with the most knowledge and who have done testing on the use of the product.
Second, solid lumber shrinks when dry, so once the house is complete and at equilibrium with the surroundings then the rim joist will not be touching either above or below (or both) and thus will carry no vertical load. So, the entire vertical loads of walls and roof above will rest on the joists themselves in compression. The joists are designed to resist bending and do that quite well, but with a relatively thin web are not so good at resisting concentrated compressive loads. It is for this reason that some engineered joists, particularly those with a truss design, contain solid blocking (with the grain running vertically, by the way).
I didn't quite follow your description of what you do as an alternative. But, you have to be careful that the structural elements must work together as a system. It sounds like you are creating a cripple wall, structurally like a header, to support the wall and roof above. But if to do that you have to reduce the length that the joist bears on the wall you would weaken the floor structure. The ends of the joists have to bear on support below for a minimum length, at least several inches, possibly more. If the joists just catch the edge you'll have concentrated the load on too small a portion of the joist.
The other thing, of course, is that the nailing of the rim joist into both the top and bottom of each floor joist keeps them from racking, all toppling to one side like a bunch of dominoes. If your alternative method doesn't do that then you have weakened the floor and it could, possibly, fail. Many structures fail during earthquakes for exactly this reason, though it is cripple walls surrounding a crawlspace that fails in this manner.
So there are a number of structural reasons why solid wood should not be used as the rim joist when the floor joists are engineered lumber.
Wayne,
When I say that I'm building on a sort of 'header' design my rim joists ... I mean that the outside rims that run parallel to the i-joists on the two opposite outside walls are built this way. They are 5 1/2" wide and fit perfectly on the top plate of the outside walls, again, running parallel to the other joists. So at the ends of the joists, where they rest on the adjacent top plates, the i-joists DO have a good 4" of space to lay on. And they are quite beefy joists spanning only 13 feet.
Again ... I would understand your potential problem as being serious, but not in my situation.
thanks -
T.
"I mean that the outside rims that run parallel to the i-joists on the two opposite outside walls are built this way. They are 5 1/2" wide and fit perfectly on the top plate of the outside walls, again, running parallel to the other joists."Again, why are you wasting your time and doing all that? Why not just sit a single 2x10 of your choice and let the walls sit on top of that like the other million house that are built?When we frame with 2x's we use a single joist/rim at the end for 2x4 walls and 2x6 walls two story or three stories. When we frame with I-joists we use a single rimboard or a LVL and the walls sit right on top of a single rim. Why are you doing all this extra work? What is so special about the walls you are putting on top of these rimboards that needs all this work when there are millions of houses built with SINGLE joists/rimboards at the end?Why not follow the manufactures instructions? It makes no sense not too. So it's worth it to you to save a few dollars on your own house to have a problem when your 2x10's shrink 3/8" later on and the rest of your I-joist don't move. What about cracks or squeaks later. You want to mix regular lumber with I-joists, go ahead.So, all your outside special/heavy walls that are sitting on them will move with them and that's alright with you?There's no way that a 16'rimboard is more money than 2-2x10's @ 16'with 2x3 in between them and 1/4 plywood on top.You know, maybe I won't know what will happen in the end result because I would never do what your doing because I know for a fact that the 2x joists WILL SHRINK and your I-joist won't shrink and the glued sub-floor spans across both I-joist and 2x rims your making up, so they are acting together. In time you will be the one to find out what the problems will be. Like I said above, why are you doing all this extra work??Joe Carola
Edited 7/2/2006 8:27 pm ET by Framer
I framed it extra heavy on the sides under these walls because these are SW walls. I don't know whether or not the E. Coast is different than here but there are four designations of Shear Wall here and some of my walls go as high as SW (shear-wall) 3 and 4 ... five being the highest. I'm going a little overboard to make them beefy both by choice and because I'm required to. It is also common here to use squash blocks ... a tine fraction of an inch higher than the joists or boards-on-edge ... to accomodate heavy loads that they do not come down fully on the joists. I am doing that WAY more than required and this includes on the ends. What this means is that the load ... yes, even 20 years down the line ... will NOT be dropping 3/8" down below joist heighth. Just try 'crushing' a 9 9/16" 2X on end. This is a small structure in terms of the fact that it is only one room on one room on one room on one room with no dividers or mid-walls. Just a rising box ... I'm not talking about a full house here. But I wanted more than just a 1 1/2 inch 'edge' for these shear walls to fit onto and, hence, the 'self-constructed-franken-header'.
thanks (for the beating)
T.
"But I wanted more than just a 1 1/2 inch 'edge' for these shear walls to fit onto and, hence, the 'self-constructed-franken-header'."You wanted more?"I'm going a little overboard to make them beefy both by choice and because I'm required to."Which is it. Is it that you wanted it that way and didn't feel comfortable on a 1-1/2" 2x, or your Architect designed it that way?Besides, what is a SW sheer wall? What is it made out of that's different than a normal 2x4 or 2x6 wall?
Joe Carola
Joe .. you mild-mannered guy you ...
yes ... I'm supporting outside walls twenty and thirty feet up and I'm a new builder, never really built before, and I wanted a solid seat for the wall above that was as wide as the wall below. Is this somehow .... 'blameworthy'?
I am quite 'required' to build these SW-3 and SW-4 Shearwalls extra strong. They require 3X's at all edges and specific nailing patterns for strength and non-splitting. Also some pretty massive holddowns floor to floor. From my foundation to my first floor walls alone, on a room of only 13 by 19 feet I'm required to use 11 6X6 posts with a holddown load of over 145,000 lbs. There is a Shear Wall Schedule that comes with the permitted plans here in King County and I must follow it religiously. I was not 'required' to build this end-header the way I did ... but I'm glad I did because it's a nice, flat, broad 'seat' for the wall above that more evenly distributes its load. I just hunted for a SW Schedule online so that you could have a look-see ... couldn't find one.
Anyway ... I'm glad I'm not on a 1.5" edge ... 'feels' safer. I don't care that it costs me extra time. I'll be living in this thing a long time. Likely die in it.
T.
Here's what I don't understand...
you've admitted you haven't built a house before, you've admitted you do not know much, but you keep arguing a point because you don't like the answer you're getting.
Why?
Here's what I don't understand...
you've admitted you haven't built a house before, you've admitted you do not know much, but you keep arguing a point because you don't like the answer you're getting.
Why?
=======================
I may view what goes on here a little differently than you and than some others here. I see it as a place to 'discuss' possibilities. And many times I have come here, asked a question, received feedback, turned it this way and that and ended up doing some sort of combination of things or -- because of something someone said which planted a suggestion -- came up with something other than anyone here had thought of. But it is also definitely true that I've come to consult, received feedback and done exactly what was said. But I always look for options ... questioning the standard protocol. I admit that, though I 'feel' this as a kind of strength, it can sometimes be a problem .. or 'lead to' problems. But overall ... I believe in constantly considering alternative approaches.
In this particular instance I have already done the rims for floors one and two of four. Already done them as in they are already cut and in place! I asked the question more to see if everyone thought that I was definitely doing it wrong ... in which case for the next two floors I would change my approach. But also, I DO think that my case may be a little different than Joe was considering ... It's basically one small room I'm building ... then another on it ... then another on it. The spans are pretty small and the joists I'm using are quite large. Also, I really trust my architect who has built scores of houses over his life and who is a very strong consultant in my part of the woods here. Well known and trusted. I checked back with him again today sharing some of the feedback with him and he encouraged me to go ahead with what I'm doing. More than adequates squash blocking and building the rims slightly large to account for some shrinkage.
If I'd asked the question earlier on ... before committing to this way on these first two floors I may have approached it differently. I'm not about to tear out what I've already put in though.
So ... that's why, I think it may appear that I'm resistant. But I do appreciate the feedback and out of everyone here who could have responded it is one builder who felt very strongly that I was committing a grievous error. Hell, everything I've ever done there's ALWAYS been someone! I believe that Joe knows what he's done and what he's doing and I truly value his view ... but I won't take it and follow it robotically ... I'll throw it in the hopper and mix it up with the parameters of my situation and take from it what I can.
Hope that answers your question.
thanks -
T.
""Joe .. you mild-mannered guy you ...""Just trying to make sense out of what you’re doing that doesn't make sense. You’re the one that is trying to invent some new way of framing and waste all material for no reason when it is not required to do so. If you feel comfortable then knock yourself out.Where not talking about trying a different technique on framing, you’re talking about adding way more material than needed. Are you going back and putting solid blocking in between all the I-joists that run perpendicular to the 2x box you nailed into them? ""yes ... I'm supporting outside walls twenty and thirty feet up and I'm a new builder, never really built before, and I wanted a solid seat for the wall above that was as wide as the wall below. Is this somehow .... 'blameworthy'?"" No, but it's just not necessary!!!!You’re obviously a new builder and you asked the questions and I'm telling you that your walls are not special and I've never seen or heard anyone do what you’re doing before and I've built walls three stories also with single rim joists.You’re the one who keeps saying that you wanted these special rim joists and your Architect is just giving you the ok sign to do so because it sounds like it makes you feel more comfortable. That's fine also, but it's not necessary.I'm telling you that your SW walls are nothing that is special where you need to build up 5-1/2" rimboards even with your 3x's or 6x’s you still don't need it. You can just put LVL blocks underneath the 6x's. “"I was not 'required' to build this end-header the way I did ... but I'm glad I did because it's a nice, flat, broad 'seat' for the wall above that more evenly distributes its load."”Again, it’s something YOU wanted to do, but it's still not necessary and required from an Architect. If that was the case every house would be designed that way. Your SW walls sound like to me that there made of the same 2x studs and sheathing as I use and nothing heavier or different except a 3x stud which is something I've never seen before but that still doesn't require the need for these special rim joists that your making.All this is something that you feel comfortable doing with your own house and that's fine. Are you doing this all the way up on top of all your walls running parallel with the joists? If so, what about all your mechanicals running on the outside walls with all these solid header/rims you’re making?“”Anyway ... I'm glad I'm not on a 1.5" edge ... 'feels' safer. I don't care that it costs me extra time””Again, that’s fine. It just seems that you don’t like what I’m saying because I don’t agree with you. All I’m saying to you is that your 2x material WILL SHRINK no matter what way you look at it and it is tied into your I-joists that WILL NOT SHRINK and there could be a problem down the road with movement and cracking or squeaking.I’m also saying that you don’t need all that built up 5-1/2” rimboard/box that you did with 2x material and ¼” plywood If that was the case and I saw that detail on a set of plans I would’ve called the Architect up and told him that I will use a 5-1/2” x 9-1/2” LVL for the outside box/rim instead of what you did because that LVL wont shrink. Cut it to the length and drop it in and your done.Joe Carola
Edited 7/3/2006 7:47 am ET by Framer
Joe,
I do hear you ... and I do appreciate your input. I don't mean to sound as if I "don't like what you're saying". I asked for staight, honest input and you've gone out of your way to provide exactly that.
In looking at this whole situation now after a little rest and time have passed I do now question my approach pretty critically. It is absolutely clear to me that the factor that prompted me to call my architect and ask him if it wouldn't be ok to us 2X's instead of versa-rim is the fact that I'm building basically a small house by myself on a very very tight budget. Any money that I can 'safely' save at any point along the way, even if it means a little extra work, I'll try and save.
Using lvl doing it my way with a double lvl along both sides woulda cost $471/per. flr. (Doing it your way with only one on edge along the side woulda cost me about $332 per floor.) Lvl around here runs 5.35/ft. But using 2X10, even with my overbuilt frankenheaders costs me under $100. Doing it your way, only 68 dollars. 2X runs around $1.10 lf. So it was this that prompted me to ask and when he said "if you can save several hundred dollars overall by doing a little extra work I don't blame you, go ahead" that was all I needed to hear. To me, in this situation, the difference between something costing 470 $ -vs- 96 $ is pretty motivating. I also switched from holdown anchors to the Simpson equivalents in straps because the difference in cost per floor was nearly $800 -vs- around $200 ... same holdown equivalency.
This may sound insane to you, but if you were working under the financial strictures that I am and it was your own project and you had the time and worked carefully AND you didn't have the strong feelings that you've formed over the years about it ... well ...
The final consideration on matters such as these may be the ol' "if I had it to do again..." And I think now that if I had it to do again I may bite the financial bullet and use the lvl. And this, partly, because this morning in thinking about it I realized that I've alREADY had some problems related to using the 2X's there along the rim due to their 'instability' with warping and movement. (Hadn't put that together yesterday) .. and if I am in for an eventual handfull of problems like this, then I clearly made the wrong choice. We'll see. I think now that I'm going to go ahead and complete this ceiling/floor that I'm working on just using the 2X's that are already nailed/screwed/glued in, and then I'll have this same choice to make with the next floor and the next, which will be the flat rooftop.
Again, I appreciate your excellent input. This issue had come up tangentially in other discussions and it has been good (for me, at least) to look at it head-on.
thanks -
Terry
""This may sound insane to you, but if you were working under the financial strictures that I am and it was your own project and you had the time and worked carefully AND you didn't have the strong feelings that you've formed over the years about it ... well ...""Terry,If I didn't know what I know now and didn't think that mixing I-joists with 2x's was a bad idea, I probably would've done it. Since I know what I know now and money is tight I would still pay the extra money now to do the job right or not do it at all. Our 2x10's are usually 9-1/2" -9-3/8" and I-joists are exactly 9-1/2". If a guy who doesn't know the difference about mixing the 2x's with the I-joists he might think it's alright to do so not taking into consideration the shrinkage problem later on.When we use 12" I-joists they measure 11-7/8" and our 2x12's measure 11-1/2" - 11-3/8". That right there they are 3/8" - 1/2" difference in height. That's why I would rather use the rimboard or an LVL because they're the same height as the I-joist and they don't shrink. When I have to block underneath a point load, I always use an lvl when using I-joists because they don't shrink. If I'm stick framing I use all 2x material.I'm not trying to be a hardass with you; I'm just trying to help you do the right thing. I honestly can say you did the right thing in your mind when you did this. There’s nothing I can say to you with that. I'm not trying to tell you how to spend your money, where all trying to make a living and feed our families. All I was trying to do from the start was tell you that mixing and matching floor joists with I-joists and 2x material is not a good thing to do because the way the 2x material shrinks and the I-joists do not shrink.Just wondering about your mechanicals on the outside walls also.I hope it all works out and everything goes smoothly for you.
Joe Carola
My question is how are you insulating these franken-rims you're building. We call them hollow headers because there is no way to insulate them, and they are just full of dead air boxed in between the lumber. I also imagine if you have a 4 story structure you will have continuous bolts form the from below the sill plate of the 1st floor all the way to the top plate of the 4th floor, and this is what holds your shear walls together.One more question, after building the headers running parralel to the joists, what about deadwood for the sheetrock ? Add a nailer to the end joist ? I don't like the idea of mixing and matching, and I would feel more comfotable with either an I-joist or rimboard on the walls, with blocking in the intermediary. JK
Newbuilder,
I was going to ask you where you are building, but then you mention king county. I'm in Kitsap. Which part are you in?
So what exactly is the detail that the engineer gave you? Can you scan it and send it to me?
We've worked with a few different I-joist companies, and it's pretty easy to work with them on these engineering details.
Typically we don't have such massive shearwalls on outside walls because the outside walls are so long, thus requiring smaller holddowns and there is less "crush" under them. Have you checked out Thor's book on shearwalls? http://www.shearwalls.com I highly recommend it and even showing your engineer. I've shown mine to the inspectors on occasion.
When we do have shearwalls that are "bigger", then we can just put blocking made of rim material between the joist in addition to the rim. I think the Roseburg rim we usually use is 3000lb/foot crush.
Email me or post here with some more info. Hope you are enjoying the weather. We've been starting at 6 and getting off at 2-2:30.
Tim,
Wow ... that book looks absolutely excellent. I'm just wishing I had had it at the outset when I began putting this thing up last Autumn. But then again, my project, though unusual, is pretty basic. As I've said here before, a room on a room on a room on a room... tha's it!
i don't have a scanner ... and I'm ok with contiueing from where I am .. thanks.
My only 'worry' at this point is that the inspector is going to come by and say "tear out those 2X's and put in lvl. An impossible situation, that would be. I'll be thinking a bullet into my brain might make the most sense in that case.
We'll see -
thanks
Terry
Here's another suggestion.
I've been framing for a while. 98% of the time we use TGI's. They seem to work great. I deciced to put them in my addition of my 120 year old house. The addition was for a dining room so I put them 12" O.C. to handle the buffets. I found the floor to bounce much more than all the other floors in my house.
Of course the other floors were true 2X10's and 2x12's of white oak, my old disgruntled carpenter foreman said I needed to stay with the solid lumber.
The way to put down a floor is with solid lumber. 2X12's of doug. fir. No bounce, and there's no worry about shrinkage as the rim is the same as the joists. When laying out, go ahead with 16 O.C.. Don't worry about plumbing as it is easy as pie to header off any cuts in the joists.
I'm a new builder -former framer- and all my houses will be 2X12 doug fir floor joists. I guarantee I won't bounce in my recliner when my dog walks by.
even a stopped clock is right twice a day
A vote for old school ... love it!
OK - so you are building these 5" wide "header-rims". Are the ends of the I-joists sitting on the double top plate of the wall below? - or are they sitting on the mudsills that sits on top of the foundation? if so, what size is the mud sill? or, are the I-joist ends supported by joist hangers?
OK - so you are building these 5" wide "header-rims". Are the ends of the I-joists sitting on the double top plate of the wall below? - or are they sitting on the mudsills that sits on top of the foundation? if so, what size is the mud sill? or, are the I-joist ends supported by joist hangers?
The ends of the I-joists are sitting on the double top plate .. 4" on each end .. of the walls at either end.
t.
T,
Kin I have sum uh yer payshience?SamT
>> The ends of the I-joists are sitting on the double top plate .. 4" on each end .. of the walls at either end. <<
Having trouble forming a mental picture... If the 'rim joist header' is 5.5" thick (2 2x10s + a 2x3 spacer on the flat), are the wall double top plates 2x10s or what? (5.5" thick header + the 4" you mention above = 9.5").
What is the wall below framed with - 2x6?
Maybe your 'rim joist header' is just on the rim parallel to the joists?
How about a pic?
Edited 7/4/2006 7:46 am ET by Matt
Matt,The guy has 2x6 walls. His rim joist is a 2x10 where the I-joists bear, leaving him 4" of joist bearing on his 2x6 top plate.The "Frankenrims" in question are atop the walls that run parallel to the floor joists, so there aren't any I-joists bearing on those walls.Bill
OK - I got-cha. I normally just add an I-joist there, or even just use up some scraps of I-joists. I'd even be comfortable with nailing a 2x? on the inside of the engineered rim board to give something more for the walls to be supported by. I share the guy's concern about supporting the wall with a rim-board only, but I think this thing about his solution is cheaper is baloney.
Edit: Aside from the dreaded shrinkage ;-), one good thing about this guy's approach is that any window or door openings below the "franken-headers" really don't need headers, unless the openings are rather large.
Also, in regular stick built platform frame construction, it's not totally uncommon to use a double 2x10 for these joist-parallel rim joists. It's a nice little quality added feature and this is a good place to use up the longer off cuts and otherwise undesirable lumber. On the other hand, if my boss ever noticed it he would probably think it is a waste of money... Also though, as far as this guy's 2x3 spacer - I see what he was thinking, but, personally I think it adds little to nothing, and if anything is just a dead space that can't be insulated.
Edited 7/4/2006 2:28 pm ET by Matt
Anybody remember 'ol Bosshog's build??? These threads read like a book. I used to frame in California and very familiar with shear ( we had other names like F#@$%^ing wall, etc.).Shove all that lumber in there, mixing engineered and common lumber, making room for mechanicals, not fun. Oh yeah, All thread, rod or strap through all the floors....I shoulda bought stock in Simpson.Newbuilder Guy: Have fun, you are obviously determined to do this the hard way. There is a wealth of experience here and from reading posts, you've said thanks with a smile and did it your way anyway. Some guys need to figure things out for themselves. REMEMBER: Your time is valuable to yourself and your family. Techniques and skills and ideas presented here are because most guys here are builders and passionate about it. Nobody here gets paid for this. Proven and reliable methods save you time, money, headache, problems down the road and reasonably safe to do.A free exchange of ideas is important, yes. Bring something to the table if you have it. BUT, when a dozen guys who have been building for 10-20 + years who have seen all the tricks are hinting and ahem-ing to you....Take a step back and think about it. Some pics would be nice to see what you're doing. If you're going through all that trouble, the view must be incredible!!
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Judo Chop!