Quote Originally Posted by Jim Becker View Post
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On the grade board, they are PT for ground contact and it's now common to tape/coat the bottom. That, combined with stone that drains really helps prolong life. But yes, proper grading, as with any kind of building is absolutely essential. When you do see rot on grade boards, it's most likely going to be because of inattention to ground water and/or other water leaks from above.
I wonder if the quality of pressure treating has decreased, at least for what is sold at the box store. I had a low 10x10 deck for the dogs not in contact with the ground - PT deck boards rotted in places enough to stick my foot through. Rebuild - the same thing happened after about 8 years. Rebuilt it from scratch with Trex.

I also had a small deck on a slope 3-4' above the (well drained) ground. Not only did the PT deck boards rot through after about 10 years but the beams and joists did too in places. The only thing that didn't rot was the posts in the ground. I replaced the entire thing, decking with trex this time.

JKJ