OSB or PT ply?

I am putting up a kit shed on a 2x6 PT framed platform. The kit includes a plastic floor. Can I cover the platform with OSB or do I need pressure treated ply?
PS: Yes, my first instinct was to build it myself, but SWMBO wants it done this year and my credibility for timely turnaround is close to zero.
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On 3/22/18 9:03 AM, Gramps' shop wrote:

If there's any chance of direct contact with water, go with PT. I'm not sure what the plastic floor is, but couldn't you just use 1x decking boards?

LOL! Happy wife, happy life.
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On Thursday, March 22, 2018 at 9:42:39 AM UTC-5, -MIKE- wrote:

Well, hopefully. At least your chances are better!
I don't know what plastic floor is, either. But when I build something lik e your shed that is outside and I am looking for some moister protection, I staple down a couple of layers of Visqueen (black plastic sheet) over the framing then add the subfloor. PT is a great idea, but locally, they NEVER store it correctly so it is soaking wet. Since I like to "glue and screw" the sub floors I can't do that either because the PT ply is too wet for th e adhesive to grip permanently.
When installed the wet PT it shrinks, moves, and the nails pop. Again, thi s is because of their storage methods not a product fault.
With that in mind I put down the plastic over the framing, screw down the s ub floor and go on. The alternative would be to buy your PT, then sticker it in the garage or under a tarp for a month or so before using.
REALLY like the idea of the epoxy floor as per Leon. It makes the floor ea sier to clean,cuts the wear factor down by a huge amount, and even makes th e floor have more stability against movement. Put it on while the floor is perfectly clean and the coating will llast for years.
Robert
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On 3/22/2018 9:03 AM, Gramps' shop wrote:

If the wood part of the floor is going to be facing the ground with the plastic floor on top, I would advise pressure treated.
If the plastic floor goes on bottom and the wood part of the floor will be protected from outside moisture go with what you like.
I painted my Tuff Shed floor with an Epoxy paint to protect against scuffing.
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On 3/22/18 9:55 AM, Leon wrote:

That would be a real moisture trap, wouldn't it. I think I would go for either a composite or at least rated for ground contact.
I can't tell you how many decks there are around here that have rotted joists where the decking boards sit against them and trap the water run-off. I've seen joists rotted out, half of their depth, in under 15 years.
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On Thursday, March 22, 2018 at 10:16:16 AM UTC-5, -MIKE- wrote:

Unless it is a pier sitting on a footing or poured in concrete, I don't so anything that has direct ground contact. Like you, I have found that groun d contact causes the "treated" or "rated" wood to rot away quickly, but mor e importantly, become unstable. Also, if the building shifts, ground conta ct framing is almost impossible to repair after it conforms to the ground.
I don't know what the life expectancy is for treated wood these days, but i t doesn't seem to be much more than regular untreated wood. The last fairl y large deck repaired a few years ago, I painted all the substructure repla cement members with a couple of coats of oil based paint before installatio n. Put the PT out in the customer's yard for month to stabilize, the paint ed, then used the wood. Much more satisfactory than my previous effort at which the treated wood shrank so much I was embarrassed and replaced it for free later on.
Don't trust pressure treated at all these days.
Robert
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On Thu, 22 Mar 2018 07:03:59 -0700 (PDT), "Gramps' shop"

I like the 5/4 pressure treated deck boards - I used them for flooring on my 10 x 12 garden shed. Cost difference shouldn't be a big issue on a small shed ? John T.
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On Thursday, March 22, 2018 at 7:04:04 AM UTC-7, Gramps' shop wrote:

If it'll get some moisture, and if there's a wood floor over plastic, the wood won't dry well. So, I'd consider polymer deck material instead of wood for the floor. OSB is not much good when it gets cycles of moisture, and plywood isn't a good wear surface, though paint can help.
The wood won't last long, though, if it gets wet and has paint and plastic on its surfaces.
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On 3/22/2018 2:59 PM, whit3rd wrote:

If it is a decently built shed the floor should not get wet, except for a small amount now and then if the door is open and it is raining. Occasionally getting a little damp and allowing to completely dry should not be an issue.
If the shed leaks there are many more problems that will come up in addition to the floor issue.
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On Thursday, March 22, 2018 at 7:04:04 AM UTC-7, Gramps' shop wrote:

I wouldn't use either, if solid wood (either close framing or ventilation and subfloor-type planks) was an option. OSB doesn't take strain and moisture changes both, it'll sag. Wood preservative painted-on should suffice, or PT. OSB will be less structural than you want, plywood is pricey.
Heck, it's a shed; let the floorboards squeak.
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On Thu, 22 Mar 2018 07:03:59 -0700 (PDT)

does the kit recommend a sub floor
plastic over any kind of wood seems like a bad combo
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