T&G Plywood vs. CDX vs. T&G OSB

[pioneergal]

Once again we are at the drawing board trying to make the right decisions.

We got set back a few weeks on our subfloor project  but we are now about ready to tackle this project.

First I have a question.........

Instead of using 3/4 T&G plywood we have thought about using 4x8 sheets of CDX.
Would this lessen the strength of the subfloor?
The reason for asking is because we have found a great price on the CDX that would save us a good amount over the price of T&G.
But, on the the other hand we want a strong subfloor even if it means buyng to the T&G.

Also, a few people have tried to persuade us to purchase 3/4 T&G OSB instead of the 3/4 T&G plywood or the CDX.
What think ye of this idea?

Looking forward to the replys!

Have a great day!

[jraabe]

You want the T&G product unless you are willing to add blocking at every panel joint to support the floppy edges.

OSB T&G is fine if your subfloor won't get too wet and you don't expect to have to live on it for awhile.

I lived with a painted plywood subfloor for several years before we had the money for finished floors. OSB is nasty for that use.

[RAB]

I have used all that you mentioned in all types of weather. These are my opinions of other products based on actual use.

-CDX needs blocking and should be used sparingly as John mentions – I have used it to finish out last 4" of a run or in a concealed spot.

The rest all T&G products –
-Comply has better edges but does swell with rain and is not as strong as plywood.
- T&G plywood can vary in quality.
-OSB is just as strong (floor rated) as plywood – water can cause it to flake and swell.
-Edge Gold (not to be confused with OSB with gold edge paint "gold edge") is a tighter grained OSB, holds up well with rain, quality wise is well made, but is most expensive of group.

Edge Gold will have higher cost, takes less labor due to its quality (square with good T&G) but it's still my choice. Of course other regions might have products just as nice and one also should be aware of your final finished floor as this might change your selection process.
Happy subflooring -  

http://www.rsvpcomm.com/weyerhaeuser/edgegold_bro_09.pdf

[JRR]

If you can buy the CDX at a REAL bargain, perhaps you should consider installing two glued-together layers.  

By starting each layer in different corners of the room, common joints would be minimized.  The few "common joints" can be stiffened by sandwiching-in a few connector plates.   ... or blocking can be used, as mentioned.

I would expect this would be a stiffer floor than a single layer T&G, of any material, of the same total thickness.

[peg_688]

For what it's worth we use Edge Gold  OSB like Ryan . WE geta roof on it ASAP , never have left it to the weather for over a month so that's all I can talk about . On Edge Gold .

 I have had delam problem with T+G plywood in the past under the same situation . Cover ASAP , we where not fast enough I guess.  

 If you use Edge Gold and it swells , that "generally " happens at cuts , you could back prime your cuts as you go , and if it's going to sit in the weather for a bit . I Think, now I've never done this , so this is out of the box thinking , Why not buy some mid range clear outdoor wood finish .  To protect , I doubt it could hurt the OSB but don't have anyway to prove that .  Just a idea .    Another thing we have had to do is sand the butt joints witha beltsander to take out / lessen the hump . After we where "in the dry"  Builders term for "have you got a  roof "  PEG