Dave Pete wrote:
My floor was 1/2" plywood with lengthwise 2x2 supports beneath (lots of rot). I rebuilt the floor with a new PT 2x2 (cut and ripped from larger dimension lumber) floor framing sandwiched between two 1/2" PT plywood surfaces, along with 1.5" of foam board insulation in the cavities. I also plan to run side to side some PT deck boards as three or four supports in the truck bed (fastened to the camper - I know, I could have just laid them in the truck bed).
Best to you!
Only problem I've had with using PT lumber is that the stuff sold at the big box stores is so wet that it warps and splits later as it drys out. Also, if cut (especially ripped) then there is exposed, non-PT, wood along the cut for moisture and/or bugs to penetrate. Last time I had an application for PT I just bit the bullet and purchased Redwood (2 x 6) and called it a day. Even the Redwood sold at the big box store was dry and stable and the price wasn't that much more than PT. You might consider it since you'll be using such a (relatively) small amount.