cmerk16

Is it necessary when trying to eliminate bouncy Joists to use 3/4 inch plywood or can I use half-inch?

Reason I ask is because I have a bunch of half inch sheets left over and was thinking about just using that since I had it. And then by 3/4 for where I need more.

Or just double up on the half-inch on both sides of the joists and buy 3/4 when I run out?

isola96

What is going over the floor? All subfloors in my book should be at "least" 3/4" for anything other then tile 1" of wood. But if this is cost to you double up on the 1/2" you won't have any bounce, just make shore your not to high from other rooms by doing this.

nealtw

I would think the half inch plywood wood help. Have you measured the bend that you are getting now? If you run a tight string from wall to wall an inch above the floor you can measure how much it moves when you walk on it. Do up a few joists and see how well that is working.
On another thread Bridgeman suggested a 2x4 on flat glued and screwed to the bottom of the joist and he had all the numbers on how much stronger the joist would be.

Jaz

Just to clarify for isola96, (aka Jet) the OP is talking about using ply strips to sister the joists, not as a subfloor.

Jaz

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isola96

tushay!..... Jaz, another check mate on me.

I personally don't think that will remedy much since there strips now 2x4s better and cat them even "betterer"! Lol

00Mike

"Is it necessary when trying to eliminate bouncy Joists to use 3/4 inch plywood or can I use half-inch?"

Was the structure built to code? If so, there shouldn't be a bounce. I just built a two story 2.5 car garage using my own design. Prior to building I researched on line for building codes regarding joist spans for live loads. I found that, to meet code for my situation, I had to use 2x10x12s - 16"o/c - supported by 4 glued up 2x12x16s - which were themselves supported by 2 jack posts equally spaced down the length of the garage. There was no bounce prior to installing the 1/2" plywood and it's solid as a rock. The alternative was to use 14" high laminated I beams which was unacceptable.

If you're not concerned about walking on the deck you don't need to be as critical but I don't think that plywood, by itself, will give you the results you're looking for. Plywood may greatly reduce the amount of bounce but, if the framework was under-built, it may not be a satisfactory solution.

nealtw

OOMIKE; Was there a suggestion in there , or should he just rip it down and start over?

isola96

Well I don't think it's the joists.
We're any parts of the floor sagging?
Your going to have bounce if you put 1/2" ply down plain and simple.

nealtw

isola. He is talking about beefing up the joists not putting down 1/2"

isola96

Yes Opps?!... Post withdrawn