when blocking is installed between tji joist over weight beiring walls or beams, should their be air space ? my framer says yes. he says by nailing the plywood sub floor into the blocking and nailing the blocking into the wall or beam below the joist will not roll. and the air space between the blocking and the floor joist prevents floor squeaks. is he correct?
Edited 7/29/2004 9:36 pm ET by tom
Replies
I would be leery of some venting suggestions inside the structure, as it may be a fire vent. I have seen paths inside door frames and following wire holes on homes which were remediated before I worked on them....
Scribe once, cut once!(David Banes)
venting is not the issue, stabolizing the floor joist from move side way movement is. what are the correct nailing pattern and fit tororances for installing blocking
I think you'll get your best advice from the manufacturer. They've done the testing and engineering to know the answer with the greatest confidence.
I hope I understand your question. When I block between TJI's over a bearing wall, the inspector usually wants to see the same depth TJI used as blocking. I have been able to use 2x8 blocking with 11 7/8 TJI's however. I installed the 2x8's flush with the bottom of the I's resting on the pony wall, though. That was not so much for bearing as it was for anti-rotation.
I-joists do not require blocking. The plywood forms a large diaphram that's anchored at the ends of the building. That will keep the I-joists from "rolling".
I've NEVER seen a set of installed I-joists with blocking in them in the 15 yers that I've been selling them.
If there's a bearing wall ABOVE the beam below, you may need some 2X4 squash blocks. I-joist scraps may not be allowed for that, depending on the manufacturer.
Common sense is instinct. Enough of it is genius. [George Bernard Shaw]
Your framer has a vivid imagination.
For bearing wall crossovers what you need are the vertically aligned squash blocks inserted with the webs of the I-Joists as detailed in the paper that comes with all I-joist deliveries and that you framer apparantly used for butt-wipe. If you have been denied sight of the paper, you can get it from thje supplier or find it in PDF format from the manufacturer on the web with a google search.
Boss - I was once required to install blocking for I-Joists but that was on a condo structure subject to strict fire codes and the blocking was there for fire blocks and had no relation to support engineering, so I agree with you on that. But what a pain it was to install the blocking correctly. I see why this dude wants an easy way out but if he would read the instructions, he could find easier ways than his dream is causing him.
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