OK, this may be a stretch, however this is the "tool shed" forum. I have two decks on my house, the back one is a normal deck with railings, steps, etc. The front one has a roof which attaches to the house so it's a porch I guess. When I built this place I wanted NO exterior painting, etc. So, it's vinyl siding, aluminum trim and soffits, and pressure treated deck and porch. As I recall, the pressure treated wood came in three grades and I went for the middle one. I haven't treated them and they have been there for about 9 years so I'm a little behind.....:-)

I googled deck waterproofing/finishing and got a ton of hits, all selling something, and contradicting each other. There's one outfit out there that sells a pre treatment, treatment and post treatment. BS and other comments thereunto pertaining.

The deck on the back has significant green stains from mold/mildew that's new this year due to the fact that it just hasn't stopped raining.

I was going to scrub the greeen areas with a bleach solutiion and then rinse and allow to dry. Then, borrow my brother's power washer and blast both decks to get rid of any ground in crud, etc.

Checking in the barn I discovered an almost full gallon of Thompsons water seal, reading the instructiions, one of it's uses is decks. Further, it provides a slight darkening of the wood (regular product, not one with a stain included) and as some bleaching has occurred that seems a reasonable way to go.

So, what I think I'm going to do is a light bleach solution for the green areas, power wash, let dry thoroughly, then apply the Thompson's with a pump up garden sprayer, maybe put a long handle on a roller to even it out.

Comments, observations, and OMG's are welcome.

Thanks for your time,

Ev