Plywood Direction Effect On Floor Bounce Over I-Joist

Originally Posted by wallmaxx

there is no grain in obs or any pressed product. Staging a lam at the mid point or close reduces deflection to almost nothing. read you stuff. lateral movement is gone with brid
ing. Think before you speak? ugly dog also?

OSB =

oriented strand board...the fibers are laid down somewhat directional in the glue before pressed. Over 14 1/2", the plywood is weaker one way than the right way.

I just went through this last week, decking a house. The cut guy was trying to use up all the scrap rather than cut full sheets. He sent me up a triangle cut from the plywood in the wrong axis direction. I asked for a new piece and had to explain that it was too weak to walk on.

Sorry B-man. "Your data on the Mig is inaccurate."

And what's with dis'in a man's dog? Be nice...be professional.

Originally Posted by personalt

The 9 1/2" ijoists I am using are rated for a 16' 8" span for L/480 deflection..

The house spans about 28 feet in width. In the back part of the house I ran the ijoists accross the house and there is a middle wall supporting the ijoist midspan.. That section of the house is fine as far as boucing.

However the front part of the house there is one room accross the whole 28' feet. This room is abot 14' deep. In this section of the house I ran my i josts front to back from the front of the house to a steel renforced LVL. This area bouces.. When looking at it from below it is not the beams that are bouncing but the ijoists itself.

I think this might be why, I started applying subfloor in the back of the house with the plywood going front to back (accross the joists).. However for the last 14' I continued running the plywood front to back (with the joists). In that area I have the bounce. Does running the plywood with the ijoists contribute to floor bounce? Everything is laid out correctly such that all my long plywood seams split the ijoists. Everything is glued and the crap was nailed out of it.

Is the direction of the plywood the major factor here?

I have three possible soltions
-Renforce both sides the I joist on both sides with rim board to make them stiffer. This is what is shown in GPs manual as a way to renforce cantilevers so should be helpful
-Add blocking at the mid point. I think this might be helpful as the ijoist seems to roll slightly as it starts to sag plus tieing them together will distribute the load somewhat.
-Add new i-joists in between these making the ijoists 8' on center at that point.
- Add filler block and anohter i joists (double them up).

Any recomendations? I dont like the idea of going 8" on center as that will make hard for highats.

Adding blocking is cheaper then renforcing but if I need to reinforce the ijoist after adding the blocking I will end up ripping the blocking back out. So maybe add the rim board to both sides of ijoists first and if that doesnt cut it I can then add blocking to that?

Was not changing my plywood direction when the joists changed direction my problem here?

gp manual is here(page 23 of 56 shows the method I was thinking)

http://www.gp.com/build/product.aspx?pid=1390

Originally Posted by neolitic

The joke is you!
Doesn't matter how many micro-lams
one puts under joist, if the plywood
runs the wrong way.
BTW: The OP is 14 months old.
Maybe it's been taken care of?

Originally Posted by borat_borat1950

there is no grain in obs or any pressed product. Staging a lam at the mid point or close reduces deflection to almost nothing. read you stuff. lateral movement is gone with brid
ing. Think before you speak? ugly dog also?

Originally Posted by borat_borat1950

1 Question, why are all you GC's on the framer forum? You screw us down on footage and then come here to rub it in on how stupid we are!! Nathan needs to create a forum for GC's who are all about themselves. I may get cut and thunked as the mod said, but I'm not backing down from GC's who no nothing!!

Originally Posted by borat_borat1950

So when you spout off about plans and spec's and engineers, and then in the next word say the framer has to check everything or he's ****. Just think to yourself, AM I REALLY A GOD OF CONSTRUCTION, or just someone blowing thier piehole!!!!! To me your a joke.:laug hing:

Originally Posted by borat_borat1950

I am a framer. This is a framing forum, where do people like carpenters, remodlers, roffers,(yes I spelled it right), BUILDERS (THE WORST), and anybody else who is not a framer, get off on giving us framing advise!!!