TJI + Parallel walls


sbarton22

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I'm looking to add some walls to my unfinished basement. A few of the walls will run parallel to the joists, which are TJIs. The top and bottom chords are the plywood type vs a 2x type. 

 

So, my question is where should I add the blocking to support the tops of the wall?

 

The web is OSB. So, does it make sense to add blocking above the bottom chord and the top of the parallel wall gets a double top plate and the perpendicular walls get a single top plate?

 

I'm thinking that nailing into the layered bottom chord is a bad idea. Maybe I'm wrong about that?

 

I'm open to any ideas.

 

 

 

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I just looked on Weyerhauser's web site. They have a PDF on truss joist installation. Big warnings not to cut or knotch the bottom flange! Close attention to where and how holes can be cut. Floor decks are glued and nailed into the top flange, usually 8d nails at least 6" on center, closer for some situations.

They show a cross wall underneath attached with 2 1/2" screws through a single 2x4 top plate. Blocking for a parrallel wall shows it nailed through the web on each side, not the bottom flange. Looks like ceilings can be glued and nailed to the bottom flange. I saw charts for nail sizes to be used.

I strongly recommend you find the brand of joists used in your home and follow the manufacturers installation instructions! They have worked out how to do it safely. Failure to follow the instructions can compromise the strength of the system.

None of it is difficult, easy to read and understand.

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@ higtron... Well damn, that was an easy and elegant solution.  I don't know why I was stuck on laying the blocking flat. 

 

You are saying to screw it... any reason screws over nails? Which type of screws?

 

@ Wdwerker...I looked at 4 of those PDF's before I posted this and I just couldn't find the right diagram, or one that I thought would be appropriate. I'll look at it again.

 

The ironic part of this is that I asked both of the structural engineers in my office this same question and neither had any idea even though they spec them all the time. As an architect, we are taught not to tell the framers where to put the studs because they know more then we do, so I didn't have a clue either.

 

Thanks for the insight.

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Just nail the blocking through the webbing on top of the bottom cord of the joist. Use a 2x6 for double top plate and a 2x4 for the first top plate. This gives you a 1" overhang on either side that could be used as a drywall nailer if you ever choose to drywall the ceiling. Or just double top plate with 2x4 if you're not worried about dry walling ever. It's faster than notching a bunch of blocks and you can overlap the plates in corners to give you a solid connection where walls intersect.

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Just nail the blocking through the webbing on top of the bottom cord of the joist. Use a 2x6 for double top plate and a 2x4 for the first top plate. This gives you a 1" overhang on either side that could be used as a drywall nailer if you ever choose to drywall the ceiling. Or just double top plate with 2x4 if you're not worried about dry walling ever. It's faster than notching a bunch of blocks and you can overlap the plates in corners to give you a solid connection where walls intersect.

 This was my original plan, the the bottom chord is not equal to a 2x...which I found odd.  I thought it was almost a full 2". But I'll double check that.

 

I'm loving the 2x6 to account for the drywall. I'm going to use that idea in another location.

 

It's a non-structural wall, so I'm assuming I don't need a double top plate.

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I geuss because thats what I have, any 8d's would work, I'd use 8ds because you will have a short swing with a hammer I like galvanized because I think they hold better than sinkers. But you are right it probly makes no differance. Use whatever you got I wouldn't make a special trip anywhere to get something special I just happen to have just about every kind of nail, or screw in my shop because I'm always doing side work, or building something for myself.

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