So I need to stain/water seal my elevated deck and stairs that I built last summer as well as my pier and boat house. I think I'll finally have a few days coming up without rain to get it done.

What do y'all think is the best to use. I have a Graco airless sprayer I can use with 5 gallon buckets, or is it better to use a stain pad and manually do it or possibly a pump type sprayer?

I don't have any experience staining a job of this size.

Thanks.

Treated wood?

Yes treated wood.

While it may depend on it the type of stain, I just restrained a pergola and fence using TWP 100 (oil based). TWP insists that you need to back brush after spraying to ensure proper penetration of the stain. To follow their recommendations, I ended up applying the first coat with an airless and a stain pad on the 2nd. The stain mist went everywhere with the airless sprayer! This may not be a big issue with your boat dock compared to my back patio. Airless was probably a bit faster, but the stain pad worked pretty quickly (to my surprise) . If I had to do it all over again, I'd probably exclusively use a stain pad to avoid all the over spray.

I did I try adjusting the pressure on the airless, but it didn't seem to cut down on the over spray.

Thanks I'm definitely concerned about possible over spray at least on the deck portion by the house and stairs. As for the dock and pier you're right it's not as big of deal.

Use a good poison pump up sprayer and back roll or back brush to work the stain in and even it out.

We have a new"ish" pier with treated wood as well. How long should I wait before stain/sealing the decking? Also, is there a marine type stain that is more suitable for a dock than the standard?

At least three months for it to dry out some say 6. I'm going to use a pad and am using Behr Premium transparent stain. Going to clean the wood with behr deck cleaner before.

To update this. I used paint pads for the first coat and didn't really like them. They produced too uneven of a finish.

Fast forward a couple days and I found this deck brush. Perdura DECK BOSS Deck Stain... https://www.amazon.com/dp/B0768N7D2F?ref=ppx_pop_mob_ap_share
It worked like a charm. Well worth the money I spent.

I used a cheap sponge mop and it worked perfectly. Then it went straight into the trash. Easy, simple, effective, efficient.