Subfloor Question

[Devon]

So this is actually for roller derby, but I know you guys can help me!
We are setting up a track (we already have the sport court) on packed hard dirt, but need a subfloor between the packed dirt and sport court track- to protect our track, and help with the leveling. One of our guys is suggesting 1/2" plywood, but I'm concerned about cost.
It needs to cover 98' x 65' (6,370sf). We need to do it as cheaply as possible. Suggestions? THANK YOU!

 

[BillConnerFASTC]

Are you laying the sub-floor on dirt, so it is uniformly supported, or are you framing it? No way I'd use 1/2" for sub-floor on normal framing - far to thin. At least 3/4 or 7/8" ply with joists on 16" centers.

Maybe you saying you need to lay something on the hard packed dirt to just protect the track from moisture - in which case probably anything but I would look at the thinner panels for used for roofing - the oriented strand board - that have some waterproofing in them. If for reuse, why not lay poly on the dirt?

 

[Devon]

Yes, the sub-floor is going directly on the dirt, no framing required.
I am currently looking at 7/16" OSB, but it's still way too expensive.
What is the poly that you are suggesting?

 

[BillConnerFASTC]

Its hard for me to picture the track and if it requires continuous support or if it spans some gaps, so perhaps I'm just confused by your use of"sub-floor" which implies support. But then I wondered if all you needed was protection from dirt and moisture, so suggest polyethylene - like 4 or 6 mil sheets. Others may call it visqueen.

 

[Devon]

Maybe I shouldn't have chosen the word sub-floor. No support needed, just protection and possibly help leveling minor bumps of the packed dirt if it's not superbly leveled. Thanks!