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4x4 post in water

5788 Views 14 Replies 8 Participants Last post by  rms59
My first post...

I need to add two 4 x 4 posts to a small goldfish pond dock that I'm building. It will be aproximately 3 feet wide by 5 feet long and attached to the pond on one end. The other end needs to posts going 3 feet to the pond bottom. I can't use PT lumber because of the fish but I don't mind using untreated lumber. Since these posts will be immersed in water for at least 6 months out of the year (northeast) how long do you think they would last.

I don't mind replacing them once a year but is there any grade that's better?

Or, anyone have a better idea on supporting the free end of the dock?

Thanks

Dick
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What about metal posts? Structural aluminum?
Ron
you can probably use a cedar 4x4 post. or take a treated post and wrap the submerced part with grace ice and water membrane.
I'm not sure why you would even put a post in the water
Why not simply cantilever the deck partially over the pond?

Is there a liner in the bottom of the pond?
thats what i was thinking Dave,plus just because a post isnt treated dosent mean it wont leach things into the pond that can hurt goldfish [tannins and oils]
Thanks for the feedback...

Yes, the pond has a heavy gauge liner. I'm not sure about unwanted movement of a cantilever since I, or the kids, will want to sit on it. The dock is 5 feet out over the edge.

I have to test the movement of a 4 x 4....

Dick
Is this a very large pond?
That's the only thing I can think of with covering part of it

The liner will wear thru over time if there is any movement
Maybe some heavy rubber attached to the bottom of the post will help. What is the material like under this area of the pond? If its soft/sandy then the post may sink down & rip the liner

I'm not sure how PVC would hold up in the water?
Maybe a 4" or 6" pvc pipe & something on the bottom for support?

Another thought, again not sure how big the pond is -
Build the dock on top of a sealed plastic 55g drum or two ?
Scuba Dave got me thinking..... 1" Styrofoam glued to bottom of 5 gallon bucket with 4" concrete inside with 4x4 inside a 6" PVC or? Bevel corners or bigger pipe. Pipe cap glued to pipe bottom. 1" sand in pipe before wood. Be safe, GBR
All good ideas, thanks.

The pond is about 1200 gallons and 3 feet deep. The bottom, under the liner, is sand/dirt and pretty hard and flat where the posts would go so I don't think there would be too much compression.

I thought of the 4" PVC pipe on each side of the dock with 90 degree elbows and a 3 foot cross piece at the bottom. Like a "U" but don't know how to attach them to the dock. 4X4's I could bolt.

I'm kinda liking that cement pail idea too...

Dick
A cement pail would have a rough bottom I think

I like the PVC with a U at the bottom
Maybe fill them with cement for strength?
Cap the bottom & seal the pipe if you do that
I'm sure there would be some way of attaching it to the dock
A cement pail would have a rough bottom I think

I like the PVC with a U at the bottom
Maybe fill them with cement for strength?
Cap the bottom & seal the pipe if you do that
I'm sure there would be some way of attaching it to the dock
You could use a toilet flange. It has screw holes to attach it to the deck.
Ron
You could use a toilet flange. It has screw holes to attach it to the deck.
Ron

I think that's it. I will try a toilet flange on each side and PVC pipe to the bottom shaped like a "U".

Thanks for the ideas everyone, I appreciate it very much.

Dick
Not sure where you are in the northeast. But around here in NJ, you need some sort of strategy to combat the herons and hawks. My neighbor across the street lays deer screen across the pond to keep them out. One of the members here also lives in town, and he strings up mono filament fishing line around the perimeter at 2-3 elevations (trips them up).

Which reminds me. I woke up this morning to 8 holes in my pool cover. Some moron deer hopped the fence and decided to walk across the damn liner. I'm surprised he got out. One spot looks like he put all four hooves through. Hair everywhere. Nasty animals. Wish I still had my gun.
Why not just float that end of the dock?
Yep, I had a few Egrets that got some of my fish here in Connecticut. I didn't like the various methods used so I bought a plastic owl (the one's that stand about 18 inches and have a moving head) and glued it to a foam floater. As it floats around the pond the owl never faces the same way or remains in one spot. The Egrets haven't been back. :)

drtbk4ever... The dock is only 3 feet by 5 feet over water and I need it rigid so it can hold a person without being tippy. Since it's attached to another piece of dock on land I only had to support the free end.

In Winter, the 3X5 dock will hinge up bringing the PVC out of the water and will lay on top of the 4 x8 land section. The "0" below is the hinge, the "[" is the PVC pipe in water.

3x5 side
-----------0--------------------- 4x8 side attached at ground level
[
[
[
[________________ pond bottom
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