Im about to use I-joists for the first time and I’ve read some manufacturer instructions which give me some confusion. Wondered if anyone here can help me clarify.
It says to use 8d nails only to do any fastening. Is that a hard/fast rule or does anyone use anything else with equal success. Around here I can’t find 8d nails for a compressor gun or my paslode gun.
When looking at the illustration on assembling the I-joists, I see one example of where they’re terminating the I-joists perpendicularly into ANOTHER I-joist which is acting as the “band” joist and then they cover that “band I-joist” with their rimboard which is an LVL 1 1/8″ thick. Then I see another illustration which shows then only using their rimboard material as what to terminate the perpendicular I-joists in to. Is there a right way or are both ways acceptable?
When exactly DO you use rimboard?
Replies
your supplier should give a drawing showing what to use where
usually what we do:
3" gun nail to fasten I joist to sill plate
rim board (an OSB type product, not LVL) is fastened to the I-joist with 2 3/8 gun nail
Tips:
snap a line to set your rim board to first, toenail you rimboard in place
then tip your joist up and nail through the rimboard into the joist, shim if necessary under the joist to bring the top flush with the rimboard.
cut your I-joists 1/4" short to avoid bowing the rimboard out of place.
I like to lay all my joist in place first using the lines snapped for the rimboard to mark and cut to the correct length right in place
Edited 8/30/2009 3:44 pm ET by LIVEONSAWDUST
Liveonsawdust has good advice. Seems to me, if you used another I-Joist for the rim joist, the flanges would hold your I-joists back and how would you nail flanges (of I-Joists to the flange of the rim joist I?) We always used some sort of LVL or similar as a rim joist. And we nailed everything with what we called "16 Penny" gun nails. Was hard to keep from splitting the flange material though, so be careful!
Don't forget your squash blocks and cross braces (if required). My boss was always forgetting squash blocks. We almost always nailed the rim joist to the plate, after snapping a line, but it made it a little harder to get the nailgun in there to nail the I-Joist flanges to the plate.
One trick we did, that maybe you already know about was to walk two I-joists over the foundation and lay them down so the webs were horizontal. Then use them as a track and just slide the other joists across the basement from near wall to far wall (one at a time, webs also horizontal), take them off the "rails" and walk them to their positions. Beat walking them around the foundation walls!
If the supplier was given a set of plans and engineered the joists for you, they should provide you with details on the installation. If you are just buying them of the shelf, thats not going ot be the case. Either method of rim joist is acceptable. I prefer to use the OSB rim board rather than use a joist, and using both doesn't make sense. You may be looking at at detail that shows the last joist which runs parallel right up against the rim board. But on the perpendicular ends, the Rim board is sufficient. As far as nails for that Paselode, I'd use the 3 1/4" to fasten the rim board and then the 2 3/8" ring shank to fasten the sub floor. But thats only if someone has talked me out of screwing it.
>> It says to use 8d nails only to do any fastening. Is that a hard/fast rule or does anyone use anything else with equal success. Around here I can't find 8d nails for a compressor gun or my paslode gun. << 8d common, box, or what? The diameter of the nail is the most important thing though. You don't want to split the I-joist flanges - then you have a problem. A lot of those 10d framing nails are as skinny as an 8d common.
>> When looking at the illustration on assembling the I-joists, I see one example of where they're terminating the I-joists perpendicularly into ANOTHER I-joist which is acting as the "band" joist and then they cover that "band I-joist" with their rimboard which is an LVL 1 1/8" thick. << Never seen it done that way. Sounds like they are trying to sell you an extra I-joist.
As stated above, the rimboard material is probably OSB - not LVL. I think it has a lot of compressive strength assuming continuous bearing beneath. If you have to span a crawl space opening or similar, you need some 2x10s or something to strengthen it at that point. One problem with rimboard is where the rim is parallel to your I joists. This leaves you with not much (1 1/8") to nail your walls down to. Best here to put a 2x10 or something in there so your (load bearing) walls have more to sit on than 1 1/8". They want to sell you an I-joist for this location but it is mostly just a waste.
BTW - normally when you are using I-joists the lumber supplier supplies a layout sheet (and design) for free.
I agree on spanning the openings with something other than the OSB, but I don't know if I would use a 2x10. You experience may be different than mine, but when I joists were just starting the become popular, they used to do the rim joists with 2x10. They would all shrink alot more than the I joists would. I'd rather see either a I joist cut off or a double layer of the rim board. Again, just my experience with I joists.
The detail with the I-joist AND the rim board works for spanning smaller opennings like a 3' door or window in some cases. That may be why they show it. Larger opennings like a patio door, slider or garage door need to be engineered and usually get LVLs
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Ah yes... the dreaded shrinkage... :-) So, as you say, there might be a better choice than dimensional lumber.
I'm not with you on the doubled up rimboard though. Like I said, it is designed to have a lot of compressive strength but again, full support beneath is assumed.
My main point though to the OP is don't think rimboard is meant for spanning openings - cause it's not.