Hi,

I am getting ready to put down an OSB subfloor (4X8 Sheets) and am just wondering what makes the most sense to put up against the wall? The tongue side or the groove side? I seem to find no information on this.

Also, I see on most information to leave the boards about 1/8 " apart when joining the boards and not getting them tight together... this surprised me because I always see them getting hammered tightly together.

Last question, how much room for expansion should I allow around the perimeter?
Thanks,

First of all use liquid nail on the joist. This stops the squeaks and also holds the board down, If this is over and old floor liquid nail every 16" long ways and screw/ribbed nailed down.

The tongue and groove need to stay tight. The "gap" theory here is for ply on the roof of hot and cold expansion.

Also stagger the sheet runs. Next sheet is cut and 4' starts beside a 8 foot sheet Like laying brick.

I like the grove showing in my direction. Don't nail that end quite yet until the next sheet is tight and square to the first sheet. The tongue is easier to start into the grove. Many times you need a small sledge and a 2 by scab to tap/beat in that next sheet to get the grove and tongue tight and square.

21boat covered this well. Think of this if you pput the tongue on one wall you will likely have the groove on the other wall or close to it. For most of us it really matters very little.