Shed floor material ? ??

Planning to build a 8'x10' shed in NJ.
I have 4"x4" pt as a floor frame on top of 4 concrete blocks. Pretty steady.
But when I put 2" x 4" in the middle supported by hangers, 16" apart, they appear to be unable to carry have weight, and tend to bend. Do I have to change to:

1. 2"x 6" pt (Does Home depot sell this size PT wood?) or ;
2. 4"x4" pt or ;
3. put two 4"x4" beams under the whole floor frame. Of course,
those two 4 x 4 should be set on concrete blocks again.

Thank you.

 

If you use 2X4's for the floor joists, running in the 8' direction, you'll need to support them on two 4X4 beams placed five feet apart, leaving about 16" of overhang on each side. What you DON'T want to do is place the 4X4's at the extreme outside edge. Then the 2X4 joists at 16" OC will be plenty strong enough.

 

Thank you, but could you explain further what is the 16" of overhang? And the 16" OC? Now I know I have to move the 4x4 to the bottom of the joists. So it is OK to use 2x4 at the extreme outside edge?

 

You will frame the 8 X 10 floor using 2X4 joists set at 16" OC, running in the 8' direction. (There will be a 14-1/2" space between each of the 2X4's.) Your blocks will be 5 ft. (on center) apart in the 8' direction, and about 7' in the 10' direction. Your 4X4's will run in the 10' direction, with an equal amount of overhang on each end. Lay the 2X4 frame on top of the 4X4's and center it, so that you have the same amount of overhang on each side. The ends of the 2X4 joists need to have a 2X4 rim joist nailed at each of the 2X4 joists so that the ends are stable. There is no need to have any Simpson hangers at this point. Simply block between each of the 2X4 joists on top of each of the 4X4's, and toe nail either the joists or the blocks (or both) to the 4X4's.

A tip -- make your overall floor frame an inch less in each direction than what the finished size of the shed will be. (95" by 119" in your case.) Once the plywood flooring is on, trim it flush with the outside of the frame. Frame your wall flush with that as well. When you install the siding, let it hang down to the bottom of the floor frame.

 

Thank you, lefty for your detailed description.