Will a wooden pond bow out?

[Lardeelion]

All winter I planned my raised pond, using the design I've seen repeated many times: a raised pond built with 4x4's and rebar.

I was about to purchase all the lumber when my dad (who I should add is an attorney, not a carpenter and has never built anything more complicated than a dock) started bugging me about the walls bowing out. He harassed me about the problems he saw with the 4x4 rectangular design for so long that I abandoned the idea and bought a stock tank. I surrounded it with a wood frame and was able to insulate with dirt and insulation, so all in all, it worked out well for the fish, even if it was half the size I'd been hoping for.

I'm 35 years old and I still let my dad talk me in and out of things, but that's a matter for a professional, I know. Anyway, yesterday I was at the only reputable aquarium store within 100 miles and in their pond room they had several raised ponds made out of 4x4's. I asked if they ever had problems and they said the ponds had been standing for 8 years and weren't even secured with rebar. I was pretty honked. Granted, the store's ponds were a bit smaller than mine was going to be, but I feel the design was sound and I shouldn't have let myself be talked out of it.

My question for you folks: Do you know of any of these ponds in "real life" that are aged and still holding strong? In all my internet research I was never able to find out if these ponds actually hold up in the long run, which is ultimately why I let myself be talked out of the design. I never got in touch with anybody who could give me a follow-up report. However, the ponding addiction continues, so if in the future I want to build one of these ponds made with 4x4s, I'd like to know that it'll hold up.

 

[sissy]

Most 4x4's have the new salt treated wood called yellow wood and are better and safer .They also sell composite 4x4's expensive but I have seen a few here.You tube has a few .I build baskets out of landscape timbers and some are 7 years old and no warping but they do not have the pressure or moisture of water pressing against them .It does take a lot of screws and rebar to put a 4x4 pond together .I have neighbors that have veggie beds made of 4x4's but they are cedar wood .

 

[addy1]

We have our bog/pond wall build with landscape timbers, they are around 2x4 but with the rounded edges, part of it is out of water, heavy pea gravel water weight on one side, air on the other side. 5th summer coming up, till holding strong. It is a straight wall. I think you would be fine, but that is just mho. My dad did the panic thing about everything!

 

[Lardeelion]

Yeah, no matter how old I get I find it hard not to listen to him. He's really good at sounding like he knows what he's talking about even when he doesn't.

 

[TgM]

How high are you planning to raise it? I just raised mine from a 30 inch ( ground level ) depth to 44 inches, pond is 17 x 14. wanted to go higher but it didn't look right. I used treated 4 x 4s sunk 24-30 inches in concrete. Sides are treated 2x8s back filled w soil & rock. Hopefully it'll last.

 

[dieselplower]

If you build it right it will not bow. If you dont build it right it will bow.

 

[slakker]

the pressure on the wood frame is a function of water depth and not water volume. So the approximate increase in PSI is about 1/2 PSI per feet of water depth. So a 4 foot deep wooden raised pond needs to hold only 2 PSI of pressure at the bottom. So I think 2xN construction should be more than able to hold the pressure... I think moisture in the wood and natural bowing of timber will be the main source of any bowing in your frame...

 

[Tula]

Not exactly the same situation, but the pond that was here when we bought the house had rail road ties as it's structure. They must have decomposed, as the pond began to shift and settle....when we pulled back the liner, we saw the ties were rotting.

 

[Lardeelion]

How high are you planning to raise it? I just raised mine from a 30 inch ( ground level ) depth to 44 inches, pond is 17 x 14. wanted to go higher but it didn't look right. I used treated 4 x 4s sunk 24-30 inches in concrete. Sides are treated 2x8s back filled w soil & rock. Hopefully it'll last.

Well, I was going to build it 24" high. I altered my design and built an entirely different pond, but that was my original plan, and one I might repeat someday.

 

[Mmathis]

I've never made a wooden pond frame, but it sounds interesting. What is the rebar used for in the design?

 

[fishin4cars]

I have two ponds made from landscape timbers. They are 8'x8' x30" with 12" in the ground, 18" above. Screwed every 8" on every board. There is some bowing but only minimal and they have been set up a year. But now with that being said. How long of a span are you considering. The larger the span the more chance of failure IMHO.

 

[Dave 54]

I suppose if you strut the sides of the lanscape timbers it would contain the bowing out of the pond .

Dave

 

[Lardeelion]

I've never made a wooden pond frame, but it sounds interesting. What is the rebar used for in the design?

The pond is build like lincoln logs, with the rebar going down every foot or so all the way through the boards.

 

[Lardeelion]

I have two ponds made from landscape timbers. They are 8'x8' x30" with 12" in the ground, 18" above. Screwed every 8" on every board. There is some bowing but only minimal and they have been set up a year. But now with that being said. How long of a span are you considering. The larger the span the more chance of failure IMHO.

Originally I had considered a 5'x10' pond, but if I ever actually built one it might be a square. The ones they had in the fish store were probably 3'x8'.

I love how I talk about building a new pond, as if I hadn't just spent my entire summer budget on the one I just completed... Okay, let's be honest. Two summers' budget.

 

[fishin4cars]

As I stated, I built mine 8' x8' out of landscape timers, Then inside a screwed 5/8" plywood to each side to help distribute the force on the wall.. I've built so many wooden style ponds over the years and honestly about 5 years is as long as I have one last. I've never had a total failure, but over time termites, decay, water seepage, bowing, etc. have all played roles in tearing them down. Even the ones I have built now are not built or designed for long term life.