2 X 4 Wood Floor Trusses- Help

sawit

Hello all. I am new to the site and have a question.

I looked at a job this afternoon. The client wants to have us finish a basement but before we can start framing I'll need to stop a problem with squeaky floors above. The floor joists are actually 12" fabricated trussed joists. (2x4 chords and webs w/ steel plate connectors.) The spacing ranges between 24" - 29" on center with a span of about 16' in the problem areas.

I was thinking I could screw 3/4" ply to the sides of the trusses but was not sure if anyone has a better idea?

Any help or suggestions would be greatly appreciated.

Cheers
Ken-

Second Look

Squeaks usually come from subfloor or wood flooring rubbing against the nails that hold it down. I would address the squeaks from topside first.

If the squeaky floor is in a carpeted area, you can buy screws where you screw them in, then break the head off neatly and the repair is invisible.

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thom

generally squeaks are the result of the plywood sub floor sliding up and down on the nail that should be holding it down. That's why we use adhesive along with nails or screws.

If this is what's causing the squeaks the plywood won't help. It will stiffen up the floor though.

Edit: Looks like second look beat me to it by a minute.

K2

I think you will need to make deeper joist but i don't suppose you have any extra head room... If the copmpany that made the joist is still around they may have a modification for you.. I suppose there is wire and pipes going through these things and you could not slap a 2x12 or 2x10 along side each one?? ..You can probably see and measure the deflection/ bending on these things.. .. I think your plywood idea may help with the squeaks but it won't be nearly 100%... I have a few other ideas. See what the other guys have to say.

K2

Oh i think you have a bending problem. That floor is probably like a trampoline.

K2

Looks like 15' 2" is the max span for a 12 inch "Truss joist" @ 40lbs live load on 24" centers. Another manufacturer could be much less.

sawit

Exactly K2!
The floor is like a trampoline. The noise is definitely not from the nails used in the sub flooring above.
The floors above are finished with a laminate flooring and I was told by the home owner that the flooring contractor had attempted to correct the problem by screwing the sub flooring down with extra screws prior to installing the laminate. There is evidence of this from some screws that missed the trusses.

Cheers
Ken-

K2

One more thing to consider if you can't sister a full joist would be to beef up the bottom chord with a 2x6 upright. Nailing would be critical as to many nails would destroy members and too few nails would be useless.. Sooo you need an engineer familiar with truss design.

Partition wall or beam under midspan or there about???

sawit

Yes. Steel beam.

ChrWright

I've seen a few jobs with these where the framers thought that truss joist equalled a license to overspan. One was commercial layout (19 5/16" on center) with a 28' span. Felt exactly like a trampoline and we were to install 24"x24" terrazo tile---serious deflection.

Webbing did wonders for the feel and strength of the floor. Used 1/2" osb ply to both sides--glued and screwed 8" o.c.

I'd get the bounce out first...then go over topside with screws to take out the last of the squeaks...

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K2

If you have enough headroom for a beam to cut that 16 ft span down that would be my first choice... Sounds like a fun project. Show us some progress pictures..

K2

Oh and welcome to the forum Sawit. Most of the guys are still at happy hour.

sawit

Gee I wish I was at Happy Hour

It's been one of those weeks!!!

You know the kind I'm talkin about-- Any week that begins with a Monday SUCKS!!!