plywood subfloors

[louky]

I've always wondered   Most info I've read on T & G subflooring (plywood) recommend leaving a gap between sheets. (So much in one direction so much in the other)  Is this gap compensated for in the dimensions of the sheet?  In other words, if you maintained a 16" cc on the floor joists, and the sheets were a true 4 x 8, and you left this gap, sooner or later the joints wouldn't be centered over the joists?  How does this also apply to roof sheathing?  Thanks

[jb daniels]

Ray...not  a professional here, but I do know on your roof sheathing, they now require (code here) spacers between each sheet...they are just small metal clamp-like things that simply slip on between edges...I used them on the entire roof...easy to do and they give you the required spacing...I did not use them on the floor...

[Dennis Kuhn]

Ray,  Actually you can't get a true 4 feet out of the Georgia Pacific T&G subflooring.  I think it is a full 1/4" short.  Which is way to big in my estimation.  I had to span 16 feet and when I got over with my fourth sheet I was almost 2" short.  

A contractor friend told me in the past they had to guard against creep because of the spacing.  Now I think they compensated for it but way to much.

The 8 feet is 8 feet.

[louky]

Dennis:  Thanks, this was the info I wanted.