Yes on the Penofin, it is an accumulating product. My personal experienece says 2 coats first year, then at 18 months, then 12 months from there on. At first it is a little more work. I personally have a 800 sqft deck on lake house, I like to rinse on saturday with a mild bleach solution, then on Sunday apply a coat of Penofin. I have found if I use a "wringing"type of mop it goes down fast(1 hour to apply and back wipe, make sure you backwipe as it will get a heavy residue(buggerish) if left. This is usually what people do not do properly, then state "they were not happy with the results. I have seen alot of people leave IPE untreated(which I do not like), I think it stays cooler to walk on, as a side note! Penofin also makes products specifically for PT wood that is great for posts etc, when trying to get a complete look on a deck. I hate to sound like a commercial, but I love this stuff.