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Old 03-19-2012, 01:22 PM   #61
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Securing plank subfloor to joists?


Ha! I would LOVE to have Holmes come in and redo everything, as long as DIY was paying for it...

Given the fact that I am worried, should I go ahead and sister the joists (at least every other one)? Would it take a special grade of 2x6s to accomplish this? Would this be extremely pricey?

Or would bridging be a better option?

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Old 03-19-2012, 02:31 PM   #62
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Securing plank subfloor to joists?


Quote:
Originally Posted by duffman56
Ha! I would LOVE to have Holmes come in and redo everything, as long as DIY was paying for it...

Given the fact that I am worried, should I go ahead and sister the joists (at least every other one)? Would it take a special grade of 2x6s to accomplish this? Would this be extremely pricey?

Or would bridging be a better option?
If I was in your position I would sister the joists,
A 2x4 or 2x6 perpendicular between the joists will stiffen up the play you have.
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Old 03-19-2012, 07:00 PM   #63
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Securing plank subfloor to joists?


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Originally Posted by JetSwet View Post
If I was in your position I would sister the joists,
A 2x4 or 2x6 perpendicular between the joists will stiffen up the play you have.
Is this "sistering" or "bridging"? I thought sistering was basically attaching another joist alongside the pre-existing joist (parallel, not perpendicular)?

Just took a look and there is a lot of stuff to work around down there (ducts, electrical, gas lines), so installing boards perpendicular may be easier in some places. I was under the impression that attaching boards to the joists provided more strength than perpendicular.
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Old 03-19-2012, 07:08 PM   #64
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Securing plank subfloor to joists?


Just looking into bridging - Anyone heard of "IBS Engineered Bridging"? Their site claims it provides significantly more floor stiffness than standard bridging options. Just wondering if there's any truth to their claims.

Looks like it's a product from Canada - it looks like minimum joist height for them may be 7.25" though. Also, I'm not sure but it looks like they may be designed specifically for engineered I-beam joists, and not 2-by's?

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Old 03-19-2012, 07:38 PM   #65
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Securing plank subfloor to joists?


I meant to say I wouldnt sister the joist I would but "cats" in yes bridge them if you want but thats the x effect of the joists not slanting on you,
Running cats is a straight run from joist to joist not angled.

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Old 03-19-2012, 08:27 PM   #66
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Securing plank subfloor to joists?


JetSwet - everything I've read states that the described method is the least effective in reducing deflection. Please tell me this is wrong, as this would likely be the easiest method to use.

Yet another couple methods I just saw - gluing and screwing a 2x4 to the underside of the joist. The main disadvantage of this is reduced headroom, but since that I-beam is under the joists anyway this wouldn't be a problem.

Also, Ideas 5 at the link below, which I have never seen nor heard of. It's a very interesting idea, but I wonder about effectiveness:
http://www.finehomebuilding.com/PDF/Free/021184090.pdf

I'm starting to wonder if securing the joists (though I don't know how) to the I-beam may be beneficial? Any tips on how to accomplish this? Will try and post a photo or at least detailed description tonight.

Thoughts?

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Old 03-19-2012, 09:07 PM   #67
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Securing plank subfloor to joists?


Geee, lots of catching up for me to do with this thread.

In post # 56, Duffman, you said.

Quote:
I'm wondering if the screws aren't stripping out. They will continue to turn, but aren't going any deeper. This surprises me, as the t&g planks they're going into are in good shape.
Are you telling us you can't tell if the screw is just spinning?

ED911 asked;

Quote:
Are you using fine threaded screws...if so, you need coarse threaded screws..
I hope you're using coarse, that's elementary for soft woods.

Quote:
The Ditra Handbook said to space the ply sheets 1/8" for expansion joints. Just curious - won't these fill in with thin set when I go to put in the Ditra? I'm sure it will work, as this is what they suggest, just wondering how the joints will expand if thin set gets into the gap.
Several theories about that. The latex modified mortar will bond the ply together while still compressing a bit. You want a monolithic substrate otherwise you will get movement causing cracks in the tile work. Some people on the other hand will tape over the joint or apply some caulking in it to keep the gap free.

I suggest you follow the direction based on the method you're using. I believe most, if not all bags of thin set tells you fill the space. I have always filled the gap.

Jet said;

Quote:
If I was in your position I would sister the joists,
A 2x4 or 2x6 perpendicular between the joists will stiffen up the play you have.
Ahhhhhhhh, What? again........

Quote:
I meant to say I wouldnt sister the joist I would but "cats" in yes bridge them if you want but thats the x effect of the joists not slanting on you,
Running cats is a straight run from joist to joist not angled.
Please pay no attention to the above on the long shot that anyone understood what was said.

I see OH Mike's advice in #33 of another thread didn't help. Is this enough subflooring support?

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Old 03-19-2012, 10:15 PM   #68
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Securing plank subfloor to joists?


Jaz, really?!?... You just just put all the so far advice for this op and threw it right out the window.
Stop criticizing every one Jaz!..not cool man
Now I'm whistling and laughing..... Lol

Course screws for flooring is not Elementry for a DIYer.

This really shouldn't be a issue, if all planks are screwed in then ply on top staggered right and screwed in correctly there shouldn't be any play.
Not shore what the issue is I think it's still the screw size.

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Old 03-19-2012, 11:18 PM   #69
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Securing plank subfloor to joists?


I've attached the first photo. This shows the 2x6 joists resting on the board (2x4 I believe?) which rests atop the I-beam.

What it doesn't show is all of the other electrical and plumbing that would get in the way were I to try and sister the joists...
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Old 03-20-2012, 12:00 AM   #70
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Securing plank subfloor to joists?


Having trouble uploading the second photo. We are having someone come look at the floor, hopefully this week. He installs tile for a living, and is probably the best in town (though our town is quite small). Regardless, the fact that he's still in business hopefully means he can give us some answers, and I hope the answer is
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Old 03-20-2012, 12:14 AM   #71
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Securing plank subfloor to joists?


I wish there were a simple way to TEST the deflection... Is there?

Should I hold off on securing 1/2" ply until we've figured out the joist issue? I believe I took the majority of the sag out of them. I just want to keep this project's minimal momentum going...
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Old 03-20-2012, 06:47 AM   #72
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Securing plank subfloor to joists?


Quote:
Originally Posted by duffman56
I wish there were a simple way to TEST the deflection... Is there?

Should I hold off on securing 1/2" ply until we've figured out the joist issue? I believe I took the majority of the sag out of them. I just want to keep this project's minimal momentum going...
http://www.johnbridge.com/vbulletin/deflecto.pl
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Old 03-20-2012, 10:54 AM   #73
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Securing plank subfloor to joists?


I've used the deflecto-meter to enter my specs, but to me this isn't truly testing my floor. The fact that the deflecto says I'm ok but there is still a noticeable bounce means there must be another variable involved. I meant more a way to truly MEASURE the deflection in my floor.
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Old 03-20-2012, 11:18 AM   #74
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Securing plank subfloor to joists?


Quote:
Originally Posted by duffman56
I've used the deflecto-meter to enter my specs, but to me this isn't truly testing my floor. The fact that the deflecto says I'm ok but there is still a noticeable bounce means there must be another variable involved. I meant more a way to truly MEASURE the deflection in my floor.
Do you have room in the budget to replace your planks with ply? If I was to guess I would say that the reason you still have so much play or bounce is that your planks are to narrow.
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Old 03-20-2012, 12:17 PM   #75
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Securing plank subfloor to joists?


Simple way? Screw a board to the middle of the joist and let it hang down towards the floor, attach a marker to something sitting on the basement floor (chair, bucket, etc). The board will move when the joist flexes and the marker will show that distance. It is not going to be much though!

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