lambeaufan71,
The blocks that you are talking about will work just fine as long as you bury at least 2" of the bottom stone in the ground. I have an above ground pond at my store that is made out of this type of block that is 11 ft x 9 ft x 21" deep at it's deepest point. It has been there for four years with no problems. If you want to go deeper than 2 ft than you will have to use the blocks that are 16" x 6" and 70 lbs per block. I have used these blocks for ponds that are 42" above ground and 40 ft long with no problems. The real trick is keeping the top of the top block as level as possible so that the water can be brought right up to the top of the block to hide the liner. After you fill the pond almost full fold the top of the liner over the top block. Than cut liner so it covers half of the top block. That landscape block adhesive and glue the cap stones down to the liner and the block.
Mike

I just returned from Lowes. They have some 4x4 timbers 8' in length for $6.97 and 4x4x12' ones for $12.97. They're treated wood, would this be a cause for concern? I'm planning on a carpet underlayment and 45mil EPDM liner.

I could do a 4'W x 12'L x3'D (2' above ground) for under $200 in lumber costs. This seems pretty reasonable to me. Online pond volume calculator tells me this would be 1077 gallons. I think this would suit my purposes of a small goldfish herd pretty well.

I plan on doing this in steps as money allows, and I'd probably go ahead and construct the wooden shell first.

lambeaufan71 - for a 12' long span i would be concerned about using the lumber solution. short term probably ok, but a year or 2 later with fatigue of water load and weather cycles the lumber is likely to bow and shift. Especially since you have to alternate the 8 & 4 ft. pieces to get the 12' length.

If you think the treated lumber solution is still the most attractive solution, how about a hexagon shape? If this is an option, suggest you do half thickness cuts at the ends and lap the boards at joints. Then drill through the lap joints and drive rebar to anchor them. bend the top into a hook and hook the inside of the top rail (?). This is just my thought without any experience using the lumber approach.

If you are after a 10' diameter pond, a hex shape would ROUGHLY have 5' to 5.5' sides. wasting some lumber this way but lapping ends together will require another 6" on each end anyway.

i've used the castle wall blocks to 2' high (fromt of my stream, concrete block were hidden) and have no problems with years of service (knock on wood - ;o). also used it as the edging. As MikeIL suggests, i simply placed some of block below grade for better anchoring of the base. good luck.

IMHO - MikeIL seems to be a good & reasonable "how to reference" source from his history in this forum. I 'wood' put above average weight on his opinion.

The blocks would indeed be nice, but MAN are they pricey when I lay out the dimensions in my mind! Of course, if I'd have to worry about the whole raised wooden pond collapsing in 2 years or so, maybe blocks would be the better option...

I read an article on pondlady.com suggesting that 2x12s would be an option. I was thinking using 2x12s and then setting 4x4s in concrete vertically at the corners and then again every 4' of pond length would make a pretty robust structure and would allow for a bigger pond without worry of the sides buckling from the pressure.

Man look at me...don't even have a pond yet and I've got the upgrade bug...LOL

I have a raised pond that was built in 2002 using 4x4's. It is 12ft. long and 8ft. wide and about 2500 gallons. There has been no problem with the wood bowing or shifting. My husband did put pieces of rebar down through the 4x4's. If you are interested in more information on our pond I can ask him for more details on how it is built. I probably also can get my son to take some pictures if you would like to see it.

Hi
I've had a stacked 4x4 PT since 82. Only problem has been a settling of one corner. It is 5x10,18 inches above and down another 20 inches below ground level. 4x4's were bolted together as I went up..
I redid this pool last Feb because it got over run with Marshmallow and strangler fig not because of a structural problem. I used a fiberglass tarp with no liner and was surprised to find the liner was still in good shape and never had a leak, Cost around 250 bucks.
I replaced the 1x8 cedar boards used as a cap with 1x6 Vinyl fencing material. Added a 2x8 foot glass window to one side covered the 4x4's with backer board and added some mosaic tile to one long side. I dug out the bottom to make it flat .much easier to sit pots on.
I got the glass for free but the redo still cost over 200 bucks but no longer looks like a stack of used lumber lol. gary

mscodeman - I would love to see pics of yours if possible. I've got the space, and would obviously love to have as much water capacity as possible. Is yours all above-ground, or did you dig in at all? Did you use any kind of a footer when constructing it? I'm certainly encouraged by your six years of structural integrity, since your winters are colder than mine.

garyfla - That's certainly impressive! I'm guessing you don't know what a freeze is though? :-)
The glass side must be very nice, for an underwater perspective!

At 2 ft above ground treated 4x4 construction will have a small bow on the 12 ft length. I have an above ground filter on my koi pond that I built in 1993. It is 12x4x4 ft high above ground. It holds 1200 gallons of water. The construction is of a lincoln log type with 1/2" threaded rod in each corner to hold the 4x4's together. The top and bottom course use lap joints at the corners so I have a solid 4x4 going completely around at the bottom and top. On the 12 ft lengths there is a 1/2" threaded rod every 4 ft. All the threaded rods are put thru a 3/4" hole on center in each corner and long sides. All the threaded rods have washers and nuts top and bottom and these are tighten down to clamp the whole structure together. There is 1/2" plywood lining the box. Then the box is lined with 45 mil EDPM rubber liner. When first filled the long sides of the box bowed about 2" on each side. After two years this bow had grown to about 6" on each side. At that time I put 2" diameter steel pipe 4ft from each end and set 3 ft in the ground in concrete with the pipe filled with concrete. It has not bowed any further over time. This year I have seen some fairly large cracks in the long 4x4's. How much longer this structure will last I do not know but it has been there for 15 years now. I have built quite a few vats for holding fish using this method and have found that there is no bowing with lengths no longer than 8 ft. But again these are all 3 to 3.5 ft deep.
Mike

Well, I've been shopping and googling some more. I've been intrigued by this website that shows a guy's 12'x12'x2' pond constructed of 4x6s. It's only held at the corners by rebar running through the entire height plus 1' into the ground. I WISH there was contact info on his page somewhere, because it seems to have been done in 2004 or so and I would love to find out how its held up (if it has).

I'm now considering something similar using 4x4s stacked six high instead of 4x6 stacked four high (MUCH cheaper) and going 12'x12' just like his. I'd probably be more comfortable either doing the rebar in the middle of each side also, or using lag bolts or something similar to help firm up the sides. 12'x12'x2' is 2150 gallons, and I'd dig out a deeper part in the middle because I'd really like to have some koi.

This is insanity! I had pond dreams last night, is that normal?

oops forgot the guy's website

Here is a link that might be useful: 12'X12'X2' pond website

it's panther-at-flaredev-dot-com

My pond is 3 1/2 feet deep, 2ft. is underground and 1 1/2ft. is above ground. It does not have any footer. The 4x4's are stacked 5 high. My husband said he nailed each layer of them together every 12" with 8" spikes and each of the 12ft. sides has 3 pieces of three ft. rebar going down through them, so the rebar is going 18" below ground. As I said we have had this pond for 6 1/2 years now and there has been no bowing at all.

When my son comes home this weekend I will take some pictures for you. Hopefully we can get a good one of the sides so you can see for yourself that it isn't bowed.

lambeaufan
Yes and no on the glass side lol. Since the plants have grown in you can only see about a foot into the water.
The glass is 3/4 inch thick and faces due west. Getting some algae buildup naturally. Haven't found a way to keep in clean without scuba gear, I have a magnetic cleaner but 3/4 is too thick for it fortuneately it's the type that floats. Had I had to pay for the glass I think I'd be disappointed with the results.lol.
Only frosts to contend with here and not every year. I keep it heaated to 60 min as I keep tropical fish in it.
Was a real thrill when filling the first time watching the water climb up the glass. I kept seeing it explode from the weight lol. I followed the directions on monster fish
for the installation and so far have not even had a leak.(Knock on wood!!) gary

the lumber fans have responded. sounds like many successful installations. more rebar and monster nails - I should have thought of that. good luck and happy new year.

It's time for action. I'm going 8'x8' square and I'll be using stacked 4x4s. My plan is to go six 4x4s high. My intitial excavation beneath the ground would be a 7'x7' square, leaving a 1' shelf around the outer edge. I don't have the lumber yet, I plan on digging and then building the box around it. I've come across a construction question already. The first pic below is the 8x8 square painted out, and the second is a 9x9 square laid out with 12"x12"x1" pavers. My reasoning for this is that the pavers would help to distribute the weight of the box more evenly on the ground and it would also serve to prevent the bottom layer of the box from having contact with the soil. The box will be centered on the pavers all the way around. I'm just wondering if the pavers will be able to support the weight of the full box, plus any added downward pressure once the pond is filled (although my mind is trying to tell me that most of the water pressure would be directed outwards rather than down. I might be very flawed in that thinking though).

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Any opinions on either leaving or chucking the pavers?

I am not sure I understand your construction question. If I am assume that the 4x4 will lay on the inside edge of the pavers than I am not sure why you are at all concerned about the weight of water as the water will be inside these pavers. But even if the water was on the pavers lets look at the pressure that would be on the paver. The water would be 2 ft high. To figure out how much pressure this would be first pressure is expressed as pounds per square inch. So we need to determine how much a column of water that is 24" high and 1" square. Well a column of water that is about 28 inches high by 1" sq weighs 1 pound. So we have less than 1 psi of pressure. So how much pressure is 1 psi. As an example lets take a 200 lb man standing on the pavers. Lets say that each foot on this man covers an area of 20 sq inches which is high. Since he is standing on two feet his weight is on two feet or covering an area of 40 sq inches. To find out how much weight per sq inch we divide 200 by 40. So we have 5 psi of force. So the pavers can easily take 5 psi or five times that of the water. So lets see if they can take the weight of the wood on them. If we take a 4x4 that is 2 ft long how much does it weigh. Lets just say that it weighs 20 lbs which is probably high but some 4x4's that are full of water can weigh close to that. So how much surface area does this 4x4 cover. This would be 3.5 x 3.5 or 12.25 sq inches. So 20 divided by 12.25 we get 1.63 psi and we can see that the pavers can easily take the weight of the 4x4's 24 inches high. This is true if the pavers are set on a flat smooth surface if not they may crack.
Mike

The bottom layer of 4x4s will be centered on the pavers all the way around the perimeter of the square. Thank you for spelling out for me in clear terms what was floating around in my mind. I've begun digging, and I've already discovered that tree roots last a long time underground. We had a very large maple removed that was ~10' to the left of where the shadow of my arm is in the second pic, and its roots are still very much there.

Edited to add: tree was removed about 5 yrs ago when we moved in. Gardenweb needs to add the option to edit a post :-)

OK I'm almost done.................................with the first 6" that is. And I've already got my first blister, what a cherished memory! LOL

I've added more of a shelf than what I had originally planned, that interior deep area is 5'x5' and will be 24" deep. The pond calculator tells me that will give me 1,300+ gallons for the entire 8'x8' pond. That's enough for me (for now anyways)

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I actually just now noticed that there's a gallery sub-board here, which is probably in place to discourage the posting of pics on the discussion side. I'll start a new thread over there for pics. My bad....