I have recently had a new tank/pond built, and I would like to have a pier built before it fills up. I am considering building it entirely out of treated lumber, or building the main posts and base out of steel then the top boards being the only lumber.

Obviously wood rots over time, but I have also heard of cases where steel posts in a pond rust quickly near the surface level especially if the pond is fertilized.

Steel seems like the sturdier, longer lasting option, but I wanted to get some recommendations. Thanks!

I had the same concerns. However my lake was already built when I bought the property.
I was told that current treated lumber, due to EPA rules, does not last near as long as it used to. Also heard about steel corroding.
I decided to build a floating dock. One advantage is I can move it from time to time if I want.
I am building a galvanized frame and using composite decking.

I believe the treated lumber not lasting as long anymore part. We have a trailer we bought from JM trailers here in town that can't be more than 3 years old and we just had to replace all of the decking because it was completely rotted out.

Just pulled up a deck that I made the frame out of treated lumber during Covid, 80% of the posts were at least partially rotted.

So to pile on. My generally green wife said, "Isn't it worse for the environment to use bad chemicals 3 times as opposed to worse chemicals once? And with 3x less wood."

For posts you would need to use water contact treated not the normal treated for ground contact you get at Home Depot. Our dock was 6x6 water contact posts with regular treated 2x8s for planks. 10 year old posts are like new.. Planks rot over time if not sealed but easy to swap out. Never dealt with steel or floating so can't comment on those.

A buddy recently did his in 4" galvanized and seems to think itll outlast him.

I get a lot of creosote telephone poles for free. Lots of them are close to new. Just stop and talk to the guys when you see them swapping them out. Have even had them load them for me.

I spoke with a dock manufacturer in Mountain Home Ark about building me a wood pier dock. He was the one that said the post he used to use (which was spec'd for water contact) were nothing like the ones he gets now. He has been building docks for 20 years.
On his quote was a disclaimer about the post not holding up due to the change in treatment chemicals.
From what he said I guess this treatment change has been within the last few years?

Thanks for the replies so far. So do most agree that regular steel would not be a wise option? Even with a good paint coating?

It sounds like ideally I would use aluminum or galvanized for the posts and frame, but that seems like it could get really expensive really fast.

Have you looked at steel lately? #headspin

I used 2-7/8" steel pipe for the frame and beams. The railing and staircase is 2-3/8" steel, and the floor joists are 2" square tube. The deck is Thompsonized 5/4" lumber, and it has held up well for 7 years so far. Trex would've made it bulletproof, but my God that stuff is expensive.

I wouldn't hesitate to use steel. No way I would use today's lumber for posts or a frame. It won't last.

How deep?

Ours is concrete piers with c-channel main runners, angle iron on the sides and expanded metal tack welded in place. Painted.

NICE job! Very nice looking.

The end of the pier will be in 8' of water or so.

Coat the steel in a thick poly/vinyl/epoxy if you have acces to it before pond is filled. Can help stop corrosion.

Id definitely do drill stem over treated. I know of duck blinds made of drill stem that have been exposed to harsh environments for 30 years. Id start off with quality stuff in good condition though. And then be ready to ignore the rusty look.

Build it with steel. Design it to bolt together. Have all pieces hot dip galvanized and take care while assembling to not penetrate the galvanize. If you have power on the dock be aware of the potential of electrolysis.

we built our dock in 2011 with treated lumber - 4x4s as the base. still going strong and not giving a bit. i figure even if it caved tomorrow, $300 in lumber for 13 great years is well worth the investment and I can easily rebuild if need be.

Really nice looking. Really choice.

I buried 6"PVC pipe into the ground, poured concrete into them, pre-drilled holes for hot dipped galvanized bolts (covered by the concrete), to use for mounting the wood frame.
That was 18 years ago, even with treating the "water side" with a creosote paint, the top lumber now needs replacement. But the PVC portion is great!

Cypress wood piers? Cypress will last a century in water.

Fwiw, I see steel boathouses all over the place and they last a while. Galvanized of course, but even unprotected steel can be provided with a corrosion anode, and will last a long time.

Modem Timbers are now pressure treated with a copper based solution that only has a moderate insect and fungus deterrent ability, and they rot much faster. Water immersion actually can slow this process, but it is where it emerges from the water that will rot fastest.

If I were to go with steel, do y'all have any recommendation on a marine grade paint that I could initially paint the steel with to increase the life of the pier?

If you can find it, a product called Rust Grip is the longest lasting stuff I've ever encountered