They are 4 times as long as what you see.I have joists that have rotted about half way out. I'm going to go into the sub floor and change the joists out for new pressure treated joists. I would like to make the decking a solid surface to protect the joists. How would you go about the solid surface? Thanks
With solid surface you don't need treated, they can just add confusion for which nails to use.
The better quality sheet vinyl is roof rated but that as to wrap up the 6" behind the house wrap and under the door.
I would sister on new joist 2" smaller so you can have a step down from the door.