Diy raised pond 1062 gallons

[Newandoverthetop]

Hello all I'm finaly getting around to trying to build a replacement for my current boswel pond from amazon I'm using 2x10s stacked on edge I'm aware that flat stacked 2x4s might have been stronger but the lumber to do it that way was just going to cost too much. But I'd like some oppinions on if my build will actually be strong enough included pictures of what I've done so far everything is glued and screwed I'm using #10 × 3 1/2in screws with about 2000lb shear rating 900lb pull out. Keep in mind none of the outside bracing is on yet nor is the top cap I will include a build pic of where I got my idea from. I will be using 3 vertical 2x10s for front bracing and back. And 1 vertical 2x10 per side there will also be horizontal sections of 2x10s in-between the vertical bracing top and bottom all 4 corners will be doubled up like in the included pic as well as 2x10 for the top cap going to be using a 45mil epdm liner dimensions are 10ftx5ftx37in 35in fill depth. I'm not great with typing things out so I hope this post is understandable lol.

 

[M1A1]

I'm about to head out the door so I haven't had time to do any math but the only 2 things I question would be the distance between the external vertical supports and whether you'll have an external 'toe board' along the bottom. There's going to be a lot of water pressure pushing those bottom boards outwards so you want to keep them from moving as much as possible. Right now you only have one middle support which means 5 ft between that and the edges, adding two more so it's 2.5 ft would be a significant help. Same with a toe board that runs the length of the bottom, even just a 2x2, would help tie the bottom board to the actual bottom of the tank. Lining the interior with ply would be another option but that's more money. The top cap looks sorted.

I think one of the main reasons the flat-stacked 2x4s method is so strong is that you can put screws through each layer into the layer below, or multiple layers. This really prevents any of the boards from moving. But yeah it costs an arm and a leg these days.

 

[Newandoverthetop]

Unfortunately at this stage I can't add anymore braces across the bottom without some serrious headache as I've got 2x6s flat running the length of the bottom and the sides it is heavily glued as well as screwed on the structure is also so heavy I can't flip it over again to screw into the bottom of the 2x10 also not sure how much it helps but I also used loctite pl 3x in-between the layers of the stacked 2x10s to help link them together along with the vertical bracing there will be a toe boards in between the vertical bracing

 

[M1A1]

Ah I missed that the vertical boards were not flush with the outside of the bottom boards. Yeah gonna be hard to flip it over to get access. Would a 2x2 or something like that along the bottom work? The adhesive might be strong enough but I always prefer some actual fastener strength. The top brace & outside vertical supports are going to be key too.

 

[Newandoverthetop]

Ah I missed that the vertical boards were not flush with the outside of the bottom boards. Yeah gonna be hard to flip it over to get access. Would a 2x2 or something like that along the bottom work? The adhesive might be strong enough but I always prefer some actual fastener strength. The top brace & outside vertical supports are going to be key too.

View attachment 1520673

I was planning to have 2x10s on the bottom how you've demonstrated at the bottom and at the top but was going to ask if they will help much because there is only like 2ft or less between the vertical I still plan to fill the gaps with 2x10 just wonder how much they will be doing. Or should I go with smaller than 2x10 but have it run the full length then add the verticals right above it

 

[Newandoverthetop]

Here's a very crude drawing to hopefully help show what I'm asking with the top and bottom bracing I drew it out both ways I was considering not sure but I almost think the 2x6 brace setup would be stronger than the smaller sections of 2x10s but I could be wrong. I used abbreviations VB and DC . VB = Vertical brace. DC= Doubled corner.

 

[jjohnwm]

I was planning to have 2x10s on the bottom how you've demonstrated at the bottom and at the top but was going to ask if they will help much because there is only like 2ft or less between the vertical I still plan to fill the gaps with 2x10 just wonder how much they will be doing. Or should I go with smaller than 2x10 but have it run the full length then add the verticals right above it

Interesting and impressive build so far; I'm looking forward to seeing the progression. You are calling this a "raised" pond. Does this refer to it being aboveground rather than a "dug" pond?

Your concrete floor looks similar to mine, i.e. they both seem to have a lot of...character. How are you going to address this?

I assume this will be a liner pond? Will you hold the liner down with the top plates, then trim off the excess? And finally, how about the bottom; are you planning to lay down styro or something similar to raise the floor level between the braces to make a flat surface? I recently "upholstered" the interior of a plywood tank with an EPDM pond liner and had a lot of non-fun in the corners due to internal corner braces. A flat bottom and four flat sides would have been a piece of cake, but the added complication in the corners was a PITA.

I can't help with any of your questions. I personally have never built a tank or pond deeper than 24 inches; the added pressure of your additional foot of depth makes a huge difference. I'm watching with interest!

 

[Newandoverthetop]

Interesting and impressive build so far; I'm looking forward to seeing the progression. You are calling this a "raised" pond. Does this refer to it being aboveground rather than a "dug" pond?

Your concrete floor looks similar to mine, i.e. they both seem to have a lot of...character. How are you going to address this?

I assume this will be a liner pond? Will you hold the liner down with the top plates, then trim off the excess? And finally, how about the bottom; are you planning to lay down styro or something similar to raise the floor level between the braces to make a flat surface? I recently "upholstered" the interior of a plywood tank with an EPDM pond liner and had a lot of non-fun in the corners due to internal corner braces. A flat bottom and four flat sides would have been a piece of cake, but the added complication in the corners was a PITA.

I can't help with any of your questions. I personally have never built a tank or pond deeper than 24 inches; the added pressure of your additional foot of depth makes a huge difference. I'm watching with interest!

Good eyes and good comprehension sir! Yes I called it a raised pond just because it's all above ground people usauly think hole in the ground when they hear pond.

Yes sir it's going to be a 45mil epdm liner based setup.

You nailed it foam board insulation is exactly what I plan to put in the bottom to even things out with the center brace and flat 2x6s.

I had considered putting some kind of braces inside my corners but trying to stay away from it for the extra hassle you have mentioned.

As for my floor when you say character I assume your referring to it being completly unlevel to be honest I'd love to address it somehow but my only plan was to ignore it and hope for the best along with the fact the bottom of my build is open was hoping it would just work out without twisting the structure since the foam and liner will get to rest on the floor might be a dumb plan but best I've got.

And yes I plan to wrap the liner over the top edge and trim any excess that sticks past my 2x10 horizontal bracing so it should be held down by my top cap as well as my horizontal bracing.

Thank you for responding I know my typing is terrible

 

[jjohnwm]

I'm honestly not sure how much I like the ostrich approach ("ignore it and hope for the best", lol) with regards to that floor, but I don't really know if that's just my OCD talking or if there really is a problem. You're right that the styro will be pressed down by the weight of the water to conform with the concrete, but what happens at the edges? In the first pic, the end furthest from the camera looks like it's an inch higher above the floor than the side on the right in the pic. I worry that the weight of the water will twist the wood downwards...or will it? If it doesn't twist, then it seems that the pond liner at that low point in the floor will be significantly stretched around the corner of the bottom bracing. And, worse yet, if it does twist...that doesn't sound good.

I know that in my plywood tank project that I just finished, I put a thick bead of cheap caulking along all the inside corners to support the liner so that it wouldn't stretch unduly. That was a PITA. In your project, it looks to me as though the weight of the water will be trying to pull the wood downwards, and it will be the liner itself that will take the brunt of it.

Not sure what is connecting the layers of vertical planks that comprise the sides. Is it mostly glue? Glue is super strong if applied correctly, but is even less forgiving when the structure twists than screws are.

I am wondering if it might be best to lay a sheet of styro on the floor that complete covers the entire footprint of the pond, and then put a second layer just to fill in the gaps between the bottom braces. I think that might compress more where the floor is highest, and less where it's lowest, and thus even up the entire wooden structure? Honestly, I'm just thinking out loud, I have no idea if that will work, but I really think this needs to be addressed.

I did, once upon a time, use a type of self-levelling concrete flooring to fix this exact problem; had to build a little corral around the entire "pad" area, then poured the concrete, allowed it to level, and set the tank on top of it. That worked well, the top of the pad was literally perfect, but the stuff wasn't cheap and wasn't particularly easy to mix and work with.

You know the old saying "measure twice, cut once"...this sounds to me like "think twice, or three times, build once". Hopefully someone else can chime in with ideas and suggestions. M M1A1 is already here and always has a pretty common-sense and realistic approach to construction ideas and problems. Maybe Backfromthedead has something to add?

Sorry if I am sounding negative, but my spider-sense is tingling...

 

[Newandoverthetop]

I'm honestly not sure how much I like the ostrich approach ("ignore it and hope for the best", lol) with regards to that floor, but I don't really know if that's just my OCD talking or if there really is a problem. You're right that the styro will be pressed down by the weight of the water to conform with the concrete, but what happens at the edges? In the first pic, the end furthest from the camera looks like it's an inch higher above the floor than the side on the right in the pic. I worry that the weight of the water will twist the wood downwards...or will it? If it doesn't twist, then it seems that the pond liner at that low point in the floor will be significantly stretched around the corner of the bottom bracing. And, worse yet, if it does twist...that doesn't sound good.

I know that in my plywood tank project that I just finished, I put a thick bead of cheap caulking along all the inside corners to support the liner so that it wouldn't stretch unduly. That was a PITA. In your project, it looks to me as though the weight of the water will be trying to pull the wood downwards, and it will be the liner itself that will take the brunt of it.

Not sure what is connecting the layers of vertical planks that comprise the sides. Is it mostly glue? Glue is super strong if applied correctly, but is even less forgiving when the structure twists than screws are.

I am wondering if it might be best to lay a sheet of styro on the floor that complete covers the entire footprint of the pond, and then put a second layer just to fill in the gaps between the bottom braces. I think that might compress more where the floor is highest, and less where it's lowest, and thus even up the entire wooden structure? Honestly, I'm just thinking out loud, I have no idea if that will work, but I really think this needs to be addressed.

I did, once upon a time, use a type of self-levelling concrete flooring to fix this exact problem; had to build a little corral around the entire "pad" area, then poured the concrete, allowed it to level, and set the tank on top of it. That worked well, the top of the pad was literally perfect, but the stuff wasn't cheap and wasn't particularly easy to mix and work with.

You know the old saying "measure twice, cut once"...this sounds to me like "think twice, or three times, build once". Hopefully someone else can chime in with ideas and suggestions. M M1A1 is already here and always has a pretty common-sense and realistic approach to construction ideas and problems. Maybe Backfromthedead has something to add?

Sorry if I am sounding negative, but my spider-sense is tingling...

No I don't think your sounding negative I guess I was just thinking that if my flimsy boswel pond that shakes when I touch it put up with the floor that surely this much stronger structure should handle it but I very well could be sadly mistaking.

I'll be honest I'm in about 10,000% over my head I've never built anything before and definitely haven't built something that will be under the forces and pressures that this will so I'd love for more people to chime in on the unlevel thing.

I'm just a guy trying to make a better home for my aquatic family members I love them and the pond they are in is a safety risk just hope I'm not building something even more unsafe.