DIY Home Improvement, Remodeling & Repair Forum > DIY Home Improvement > Flooring > Help with sistering/blocking floor joists




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Old 02-27-2009, 12:32 PM  
live4ever
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Thanks Glenn, inspectorD, and travelover!

I think I read inspectorD's method a little differently than you guys did. InspectorD - did you mean a beam running perpendicular to the joists? Doesn't that need to be supported by posts?

or--

did you mean sistering along the lengths of the tops and bottoms of the joists? With that method I could use 2x4's sistered along the top and bottom of each 2x10 joist leaving room for the wires and pipes in the middle, correct?



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Old 02-27-2009, 02:25 PM  
travelover
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Quote:
Originally Posted by live4ever View Post
Thanks Glenn, inspectorD, and travelover!

I think I read inspectorD's method a little differently than you guys did. InspectorD - did you mean a beam running perpendicular to the joists? Doesn't that need to be supported by posts?

or--

did you mean sistering along the lengths of the tops and bottoms of the joists? With that method I could use 2x4's sistered along the top and bottom of each 2x10 joist leaving room for the wires and pipes in the middle, correct?
That is my suggestion. Anything perpendicular would not help unless it is blocking, or as you suggest, supported by a post.


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Old 02-27-2009, 07:57 PM  
hondadrv24
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A beam perpendicular in the center of the joists, that is supported with posts, would reduce your joists span to 7' making your 2x10s much stronger. That is what INSPECTORD was trying to say.

What is the dimension of this floor to be supported the other way??? If it is relatively short you may not need more than a post at each end, but if it is too long or you don't have much headroom in the garage then you would need to put a post or two in the middle.

another thought about the wires running through the boards now is that you could cut them and put in a few junction boxes. the problem would probably be with your drain pipes though as they usually don't like water running up hill to get out of them.

Just a couple of thoughts
Justin

eta: if you could post some pictures from the underside we may have some better suggestions for you

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Old 01-26-2010, 04:36 PM  
Todd-Beaulieu
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Obviously, this is a really old thread, but I'll give it a try...

I have a single perpendicular beam on posts as an experiment in one room. I really like it for eliminating the bounce so far, but a neighbor tells me I probably shouldn't be trying to eliminate all bounce. His example was dance floors, but I'm thinking that a home doesn't need give.

Does anyone have any experience with that topic?

Thank you.

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Old 01-26-2010, 06:24 PM  
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I've lived in homes where the cabinets with glassware rattled every time you walked across the floor. Not good.

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Old 01-26-2010, 06:44 PM  
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The joist bottoms are in tension; somebody might make high tensile strength steel strips 1.5" wide by however many feet long that you need, to be bolted to the bottom edge of the joists, once you jack up the span center.

Just two screws with sufficient shear strength at each end of the steel strip may be enough.

I don't know what the mat'ls cost vs. labor vs. inconvenience tradeoff is for this method, though.

http://www.freepatentsonline.com/5497595.html
http://www.freepatentsonline.com/5497595.pdf

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Old 01-27-2010, 07:03 PM  
Wuzzat?
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Default did some study & reverse-engineered the span tables

Quote:
Originally Posted by live4ever View Post
The joists are 2x10's, 16" o.c., with a span of 14 feet.
I'd like to sister 2x10s to the originals
Doubling the joist width means doubling the moment of inertia of its area which means you'll get half the deflection you had before, but I guess the tiles increase the loading per sq. ft. so you'll get slightly more than half the deflection.

How much does the tiling increase the pounds/sq. ft. dead load?
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Old 06-05-2013, 08:43 PM  
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http://www.youtube.com/watch?v=R_OF9KgWhzI


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