On Sat, 29 Sep 2012 17:41:18 -0400, "
I painted all the (PT) railings on my deck and front porch on my VT house.
Peeling was a major problem and I had to repaint every couple of years. Stain
didn't last any longer.

Which would make sense since PT wood is already engorged with chemical
preservatives. There isn't any available wood fibre left for the paint
to soak in and adhere to it.