FWIW, I have a plastic resin shed that I use for storing gas and other flammables outside my barn. It's the tall skinny one you've seen at HD, Lowe's, etc. I think it was originally intended for "stick" tools. Anyway, I added shelves for gas cans and the like. I'm in SE Ohiio and in recent years it's been 100 fairly often in the summer. It has never sagged or deformed. Haven't dealt with HD in years as there's not one around here. If they're comparable to Lowe's, Lowe's has product specialists that will answer your questions or immediately put you in contact with the manufacturer. Doesn't hurt to ask. Good luck, Ev

I built a 8x12 shed in MA and I put in on 4x4x16 and 2x4x16 blocks. If your not putting in anything heavy, no need for a concrete floor. Use pressure treated 3/4 inch tongue and groove plywood over 2x6 for the floor on top of 4x4x16 concrete blocks. Put the blocks on 3/4 crushed gravel. I removed the grass and dug down about 6 inches. I filled the holes with 3/4 gravel, leveled the blocks and made sure they were all the same height and in line with each other. If you are a little off, you can use regular asphalt shingles as shims. If you use multiple blocks and shims, make sure you put a layer construction adhesive between each block/shim. I spread the rest of the gravel under the shed to aide drainage.

I used vinyl and run up wall 6" are more work very well easy cleaned did gassing out side gas will pour back into container out side oil dry works on vinyl. A 2x4 table 4x4 legs pressure treated high, 8 foot long 3ft. wide works good outside gaps between boards makes easy clean off. I don't like plywood floor to hard clean. I buy my vinyl 2 foot longer and 2 foot wider so go up wall this makes corners easy to clean and around wall edges even if pole barn style wall 2x4 studs. This post was edited by gator_rider2 on Sun, Jun 23, 13 at 5:30

Years ago, i built a nice shed to keep my lawn tractor in. After some years had passed, some ground-hogs found the underside to be a good place to dig their new home! Alas and alack, those big rats ate the floor out of the shed, and piled up their diggings inside it! and, they are still there. Also, in my dirt floored garage out back, they dug the dirt floor out, and ate some of the wooden walls, and spread the dirt all around my lawn mowers and other stuff! Piled it up 2 ft. high. And, tunneled all around the inner walls. I found one hole, so i shoved an eight foot 2x4 into the tunnel and filled in around it! There is only one foot of board sticking out of the filled-in tunnel. No digging there.