Decking material questions

[John Humphries]

Hi decking experts.  I've got a few deck related questions - 

1. Our back patio is treated lumber (the green stuff from Home Depot).  When we bought the property 5 years ago, the wood was in good shape but looking pretty rough as it had not been finished with any type of paint or seal.  My immediate reaction was to paint it.  Since then, without fail, every 2 years, the deck paint that we used from Home Depot has started to crack and peel in the areas that are exposed to the sun and rain (we are on Vancouver Island and get lots of rain).  The painted boards under the patio roof still look great. Is there anything that we can do to avoid having to re-do all of our work every two years? Sand and stain? Sand and do nothing? Is there a miracle product out there that I don't know about?

2. We are building a floating deck in the back yard.  We used rough cut cedar from a local mill for the frame and are trying to determine the best option for topping the deck.  We had planned to use rough cut cedar 1x4x12s for the top, but our supplier is now out.  We can wait for them, or we can use the green treated 5/16x6x12s from Home Depot.  Given these 2 options, which would you do, and what treatment, if any, would you do to the wood, given that it will be completely exposed to sun and rain?

Any tips welcome!