Join Date: Jan 2009
Location: Regina, Saskatchewan
Thanked 44 Times in 37 Posts
Sled: 2015 XF8000 LXR 137"
Just did the floor on my tilt triton and used CCA pressure treated (doesn't affect aluminum). It may be labeled CCA or Below Grade Foundation, same stuff. I finished it off by coating it with Superdeck transparent stain (3 different oils). Stained all sides before installing and will recoat every 2-3 years (takes 1/2 hour).
Since I use superclamps front and rear, I beefed up the rear section with an additional 3/4 inch CCA PT plywood underneath for a total thickness if 1 1/4 inches to support the rear superclamp.