Raised Wooden Pond

[AaronBoi]

Hello everyone,
I plan on building a 8 feet by 4 feet pond that is 2 feet deep. I am trying to build a frame utilizing 2 x 4 x 8 but I am unsure what type of wood to use... I have come across many posts stating that pressure treated wood can kill koi fish, however, if I were to use Hemlock Fir Studs that is untreated, it will rot quickly if touching the ground or wet. I'm not really sure what wood to use. I was thinking about painting on top of the Hemlock Fir Studs to improve its lifespan. With the frame of 2 x 4 x 8, I plan on covering the frame with plywood to hold the liner, and decorative wood on the outside. Any suggestions on what type of plywood to use? I will coat the outside with some type of waterproof sealant paint. Any suggestions on what type of wood to use? Here is a link of the types of wood I have at my local Lowes area https://www.lowes.com/search?searchTerm=2+x+4+x+8
Any help will be great. Also any suggestions on filters I should buy will be helpful. It should be about 500 gallons.
I am also following this youtube video as a guide:

Skip to 7:00 minutes in to see the frame be built.

 

[addy1]

Welcome to our group!

Mine is in ground but others have done above ground ponds, they will chime in as to the best way to build.

 

[mrsclem]

Hello and welcome! I have 2 raised wood ponds. Both were built with 2x12s, pressure treated but the wood has no contact with the water. Are you planning on using a pond liner? If so, you will be fine with the treated wood. There was another member here who recently had a wooden pond built and had an issue with the sides bowing out. 8 feet will need some support.

 

[j.w]

@AaronBoi Only in-ground here.

 

[Jhn]

Agree with @mrsclem, if you are using a liner, pressure treated lumber is fine, as it won’t contact the water. You can use a different type of wood and stain and seal it for the top cap if you are worried about treated lumber leaching chemicals into the pond. Just FYI none of HD or Lowe’s treated lumber is rated for ground contact.

Personally, I have CCA treated 6x6’s as bridge supports that are in the water, and have had no issues in 10 years with fish dying. Granted my pond is roughly 10,000 gallons, so if any treatment comes out of the wood it is pretty well diluted.

 

[longhair]

My pond is 10x10 4ft deep and I used 4x6 pressure treated post. And capped the would with decking boards and Olympic stain. I would do 2x6 if I were you. That's a lot of weight pushing out for 2x4's.

 

[longhair]

Here is a pic of my pond when I was setting up the greenhouse for winter.

 

[Sparky]

Take a look at my gallery. With an 8’ span, you’re going to want 2x6 minimum framing members. Otherwise you got the right idea.

 

[AaronBoi]

My pond is 10x10 4ft deep and I used 4x6 pressure treated post. And capped the would with decking boards and Olympic stain. I would do 2x6 if I were you. That's a lot of weight pushing out for 2x4's.

Thanks for your response. What type of decking board did u use and where did u buy it from? How much did it cost you total?

 

[longhair]

I got them from the local hardware store. Lowe's also sells them deck boards 5/8 x 5 I think is the size. But remember I did the inner structure out of 4 x 6 Pressure treated timbers. Timbers,bolts plywood and insulation was around $400 I think. But mine is 4 foot deep. It's been almost 3 years since I built it. I also spaced the outer and top caps a 1/2 from the liner. Thats lets the pond over flow when it rains. I use a smartpond filter on mine. The filter also has a uv light. You can pick one up for around $90. But I also have 5 bog filters going too. If you are doing a 4x8 pond I would use a sheet of 3/4 marine grade plywood to floor it. It will help keep the sides from bowing out. And do the sides with 2x6 instead of 2x4's. I also lined the pond with 1/2 insulation to cushion the liner and keep the water warm in winter.