New pond construction. The Water Garden Pond

[Mucky_Waters]

Really sorry to hear about that Larkin, but I was seeing what looked like some deficiencies in the forming, that’s why I was hoping you’d post more pictures before it got poured.

Not really knowing exactly what you were doing there, and just looking at pictures makes it hard to follow, but it looks like one other problem you had was the forms weren’t tied together and they spread wide apart making the walls thicker in some areas than others.

Pouring concrete forms can be a bugger when things start going wrong.

 

[j.w]

Bummer Larkin and now am hoping and praying it doesn't rain for you till you can get some things corrected!

 

[fishin4cars]

I should of known better. It's funny how you can read and read, but when it comes down to getting it all done that your start realizing just how detailed all the plans must be before taking on a project of this size. I tried and tried to locate a professional pond or pool builder to come out and actually build the pond basin with no luck. Even went as far as contacting http://ippca.com/ and talked to a few certified pond builders about this project long before I started it. as many know this isn't my first pond build and this pond has been in the planning for well over two years. Now that the FIRST of what could be many mistakes could take place I realize how beneficial a good pond builder would be to have on site. Even with 20 years experience with ponds this pond is more than I bargained for. If it fails there is always dirt to fill it in. Mucky your correct. the contractor didn't have nearly enough form board support for the pour, he didn't use near thick enough form boards and the footings are not as the original design was planned. they were suppose to be L footings that tied the first three feet of the patio and the wall all together in one pour. We shot the pond today with a lazer level. There is 2.5" difference from the lowest edge of the retaining wall to the highest. I specifically discussed that I wanted no more than 1/4" difference. the walls were suppose to be a minimum of 8" thick with the two side walls being 12" he cut them back to 6" and in one spot it's only 5.3" thick. Still should be enough to hold the water pressure up that high but not as the original designed was talked about. I'm not sure how he plans on leveling the wall and I don't know how he plans on fixing the collapsed wall but he has until this tropical storm hits to figure it out.
I think it's still workable, I have some ideas to try and I talked to a fellow today that is coming monday to talk to the contractor. he has a idea for the wall that collapsed that I think might even be better than the original design. Going to take another pour and a day of forming and I'll lose aprox. 300-500 gallons of water capacity. We will see Monday how that goes......

 

[j.w]

Hope it all works out for ya Larkin, the good Lord willing! Sounds like your team of workers is trying to right the wrongs so that is a good start.

 

[Waterbug]

I know what you mean Larkin about planning but still having problems. And good pond builders are pretty much impossible to find. I've read a lot of threads over the years on poured concrete walls and many are formed much like yours were and many have much worst results. I can't believe your forms actually held, but glad they did. It's almost amazing how many times this exact same issue appears in forum threads.

Water under the bridge at this point, but if you expect this dude to suddenly get better I think you're in for more $$$ and disappointment. Building correctly isn't really that hard. Fixing a mess takes a lot more experience and skill.

To make the point...Yeah the form boards weren't thick enough, but also there wasn't enough bracing both outside and ties to keep the forms together. The 2x4's weren't even oriented correctly, the 2" side should be against the form. That's a greenhorn mistake, not just for concrete but construction in general. He used concrete mesh as reinforcement, and a tiny bit of rebar. Mesh is only to be used in horizontal slabs, not vertical walls. I can't point to a single element he did correctly.

The forms and reinforcement is what would be used in driveways and sidewalks. Tells me this dude is self taught and has never poured anything taller than 6".

This dude shouldn't be paid imo and should be responsible for removing the current structure. I'll bet he has no contractor license? Plain and simple this guy lied to you when he said he could do this. He is now going to lie to you and say he can fix it. Even if you bring in a profession who tells him how to fix it he doesn't have the skill or brains to execute correctly. You'd need to pay the pro to be on site every second teaching this dude the trade.

Luckly you're putting in a liner so the concrete doesn't have to be great.

 

[fishin4cars]

He has contractor license, Ins. and has followed all the guidlines on all his permits. has he ever done anything like this, No. I knew that from the begining. That is my fault. He's done a great job on the barn and I have no doubts he can handle building the fences which is the other main project I wanted him for. He's also doing the patio which I think he can handle without any major issues. The retainer wall, well He gave me a price and quaranteed it would hold the water pressure. he didn't lie to me, he told me up front he thought he could do it and he would try and get it done. I know I grabbed a greenhorn. I know I should have gone with a better more experienced contractor. problem i have had is finding someone that would even attempt it. Like you stated, It's going to be a liner pond, The retaining wall is primarily a safety barrier so that my little blind pug doesn't fall into the pond and something for us to sit along side the pond to feed the fish. There is only going to be about 10" of water above dirt grade. I really think that It's still a workable project but if I could for sure find someone that would come in and do it right they would be hired and I would scrape this project. But at the same point. I now have several issues to look at from this point. 1 there is a tropical storm in the gulf, If we don't get the liner in by the time it hits I have a feeling it's going to cave all the walls in and we will have to scrap the whole project. Second is I have no way to get any equipment back in the wole to re-dig. It's all shovel and hand digging from here on. (FYI, I did have three neck surgeries and my back is NOT going to be able to handle another big dig) Third is I still am in the same boat as I don't have a contractor in the area that is willing to out any more guarantee on it than the contractor I have. So, What do I do? cave it all in and start over, fill it in and scrap the whole idea, or go with him for now and see what he does? It's going to cost me the same if I scrap it or let him continue. What would you do?

 

[Waterbug]

I'm floored he has a contractor license.

There was a permit pulled for this? And the building inspector signed off on these forms? That would be sad. You're pretty screwed if your building department is that bad.

I don't know this guy or your situation. It's a long list of what I don't know about this job. I only know what I see in the photos and the little bit of what was written. You should do nothing just based on what I have to say, which I'm sure you wouldn't. I think you should post those pictures on a construction forum and get the opinions of professionals to get confirmation on what I'm saying.

What would I do? In general I would go ape. Ask for my money back, sure wouldn't pay him any more. Wouldn't allow him back on site. I would check with the state and this guy's id to see if the contractor's license is real. I really can't believe he has a license, the job is that bad. I can't believe he's ever even seen walls poured.

Going forward...
Agood concrete contractor is going to want to rip out the current structure. The best wouldn't take the job otherwise. So if you really can't find a concrete contractor who is willing to sign a contract I think you'd be better off hiring kids or day laborers to try and fix this under your direction. Your current dude is worst because he thinks he knows what he's doing and that dangerous. You'd be fighting him ever step of the way.

Hack fix top...
To fix it, if it were my pond and wasn't being paid to to this, I'd grind off all the exposed wire mesh and put a mortar cap on top, no forms. You can get back to a level top doing that too.

Hack fix collapsed wall...
For the collapsed wall there's a couple of options. One is to pile dirt back into the pond, tamping as you go and build a block wall on top tying into the existing wall. Or dig out the wall and pour a footer at the pond bottom and build a concrete block wall all the way back up to the top and tie into the existing poured walls. This is actually how the entire structure should probably have been done. The current wall sets too close to the drop off into the pond. No code would allow that.

Block can just be dry stacked and filled with concrete. Use bond beam block so you can run rebar horizontally. #3 or #4 rebar is fine or whatever you have. Run vertical rebar in every other block making sure to wire tie horizontal and vertical together as you go. Rebar has to be completely enclosed in concrete, it can't be touching soil, else it rusts and bursts the concrete. Kids can do this, you just need to make sure they're actually doing it. Try to get it as plumb as possible. Kids won't get each course perfectly level, not an issue since you'll be filling each block with concrete. I'd have them mix the concrete by hand, just make sure they don't add too much water and they tamp the concrete down inside the blocks. The blocks should be filled as you go but leave the current course pretty much unfilled.

This is not a standard building practice. This is what is easier for inexperienced worker to do and get reasonable results.

Source of good help...
Another option is to post in a concrete forum or a pond forum that has a lot of professional pond builders. You have to go really slow because each step has to be reviewed, pictures, etc. I've seen really good results with this method when the poster is willing to listen, which is rare. The people are blunt but helpful. Going slow, posting lots of detailed pictures, your plans, etc., can really get a good outcome.

Erosion...
You might think about laying your liner right a way. I would expect erosion to take down the other walls.

I'm sure in the end it will be fine. A pond is just a hole in the ground. It's only the details that cause stress.

 

[adavisus]

If there's a storm incoming on an incomplete insecure pond build, would have thought a sturdy 'A' frame to plonk a tarpaulin over the area might be good timing so rain don't collect in hole and undermine, warp stuff. Set up a pump to pump water out too, if you have one

Regards, andy
http://www.flickr.com/photos/21940871@N06/
http://swglist.wordpress.com/

 

[fishin4cars]

Plan on at least getting the liner back in place and secured before the next rains. Sorry but time isn't appearing to be on my side to take a lot of pics and go slow. We finally got the seam completed at 10:30. The crew will be here at 6am. Still have to get a shower and some sleep so the posts are at a minimal right now.
WaterBug, I hope you can read and respond before I get to far along in the morning. We are going in the direction of the block wall. That seems to be the best advice in everyones opinion I've talked to. THANKS!!! Now the question. Should I do a footing just at the bottom or all the way across the wall and take out the steps? . I hate to dig into the steps to much as they are really serving as some what support in the corners at this point. BUT I can also see that a wall all the way across would be the strongest. I've told them I want 1/2" rebarb driven into the ground, then the footing then the blocks built on top of the footing. then we can grind off the rebarb sticking out the top of the blocks once the wall is complete. I'm thinking to fill the void between the block wall and the old wall and not taking it out. It's still got a good tight vertical bond and filling in between and tying the block wall into that wall should give more support against any future cave in on the waterfall side. we are going to be getting a cement truck out for the patio anyway tomorrow afternoon so if we can get most of the wall erected then we can fill the blocks, do the patio Then the next day fill the void between the two walls, and pour the last section of patio on Tuesday morning.
Oh and by the way, I guess I gave a misconception. The Permit was for the barn, we did go through inspection on it. The pond is not. We weren't required, But could have gotten one if we considered it a pool. Since we are out away from the city we were not required by the parish to have one as long as we have a escape/steps and GFCI electrical which has already been installed and call it a watergarden. I can't go any deeper than 5' if I consider it a water garden or then it becomes a pool. So yes Our permit office is that bad. As for my builder, He's been 100% fair and understanding to this point. he knows he messed up to say it politely. he's trying to make it right. If he was being paid top dollar to do the job I would expect a better job or would run him off. I knew up front that this was a new experience for both of us. getting rid of him at this point would be a mistake, he's been by twice today and even read some of the posts and talked to a surveyor and a engineer that i know that came by to look. Everyone agrees it's messed up. Everyone seems to agree it's still workable and that I can make this work. We measured out the low spot and figure that can be the spillover. I'll put a pad behind it to make the water go well away from the pond. the high point is only 1 3/4" high in a couple of spots with a little grinding and using a motar or possible other cap most of that can be hidden in. Again not what i wanted but I do have enough experience and knowledge from the forums to come up with some kind of way to cover the uneven edges.
anymore feedback is appreciated. Believe me, I honestly feel like a complete newbie on this build, and I am reading and listening.

 

[Waterbug]

I don't have enough info about this project to make any direct suggestions. So here are some general things I think might be going on.

It looked to me like the current wall is 'A'. Hopefully there was a footer with two strands of rebar. I don't know how deep the footer actually is.

Only to show you my perspective, not saying you should tear it all down and do this way...'B' is how I think it should have been built. The problem is the width of the shelf is not wide enough for a foundation (I assume it's 2-3' wide). For example, when a pond or pool is dug next to a house it has to be a minimum of 6' away from the house (actual distance depends on local code) so there's enough soil to support the house's foundation. You see why with that wall collapse. So when you repair the collapsed wall you can use this info to try and guesstimate a hack. This is why I didn't think the current contractor should be 'fixing' the problem. To fix a problem you have to understand the why's, like why are walls built like 'B' and not 'A'. The contractor does not understand this and therefore he cannot 'fix' it. This is only my impression based on limited info.

I assume 'C' is what the collapsed wall looks like. If you add a footer like at the same depth as 'A' you'd be at high risk of soil eroding from under the footer in the future and the wall failing to some degree. We're talking about risks here, not certainties. If you put the footer at the depth of 'B' you would be reducing your risk almost to zero. I assume you'll pick somewhere in between.

Obviously few people would actually build 'B' because if they went to all the trouble of building that wall they would also opt to remove the soil shelf. They'd gain a lot of pond volume for almost no additional cost.

Plan D
You could also shore up the shelf with a retaining wall.

That would make 'A' acceptable (assuming a proper footer depth) and 'B' footer would now be deeper than needed.

Rebar
I don't have enough info to understand the patio tie in so I'll make some general comments...

I don't think the patio should be tied into the pond wall. I'm not sure on code, but I'd bet it wouldn't be allowed. Concrete patios can't be tied into a house foundation. And certainly at this point you wouldn't want to tie what could be a properly built patio to the incorrectly built pond wall. The risk is the pond wall might only last 1, 5, 10, 20 years. Tying into the patio means it would probably fail right along with the pond wall. Instead there should be an expansion joint between the pond wall and patio. Personally, I like something like a 1" gap between the two which I plant flowers or flag stone over. I like the gap because I'll probably want to run sprinkler pipe or electric there someday. Always seems to work that way.

It's a rookie mistake to think tying the patio and wall together adds strength. Proper building means each structure is stable on it's own. Rookies seem to understand they aren't building correctly and like to "add strength" but they're actually making things worst. I've done the rookie mistakes too.

As a side note on rookie mistakes...when the patio is built you sure do some research on whether wire mesh should be used. Ask the building department. I've seen local codes change over the last 30 years from requiring mesh to prohibiting mesh. The thinking is that for the cost of the mesh the slab can be made a little thicker and therefore strong enough without the mesh. That eliminates the rust risk and also greatly reduces removal costs and patio are remodeled often. Your contractor seems mesh happy.

In concrete applications rebar is not to be in contact with soil. Ever. Under any circumstances. In the photos I see rebar bent at a 90 and it looks to me like the rebar is in soil. Meaning I don't see how poured concrete is going to cover the rebar. Also, I read about "pounding rebar into the ground". I've seen this done several times over the years in pond forums. People seem to think that pounding rebar into the ground adds some strength. It doesn't. A multi ton wall, and the forces that would move the multi ton wall, wouldn't be slowed down even a little by having to pull that rebar right back out of the ground. The reason rebar isn't allowed in the ground is because it will quickly rust and that rust will travel right up the rebar into the concrete. Rust expands, just like freezing water, and busts the concrete. You can see examples of this in US bridges where salt sped up the rust issue.

Rebar has to be completely enclosed in 1" of concrete (I think, but not sure of the 1").

Footers
Some general red flags to look for...

Footers must be on undisturbed soil (below loam layer). Not back filled soil. It is possible to place a footer on back fill but the back fill has to be properly tamped. I wouldn't trust most contractors to do this, certain not your contractor. It's one of the things a building inspector does, check the bottom of the footer for undisturbed soil.

The width of the footer depends on soil. Could be anywhere between 6-16". It's worth a phone call to the local building department to find out the requirement because if your soil only needs a 8" footer and you're using 8" wide block it means you don't need any footer at all. 20 minute call can save a lot of money and time. The building department probably won't know your specific project so just ask for the footer width needed for a one story wood frame house. That's about the same bearing weight as a 4' high pond wall I think.

Footers require rebar, not mesh. Vertical rebar also to tie in the wall.

 

[Waterbug]

the high point is only 1 3/4" high in a couple of spots with a little grinding and using a motar or possible other cap most of that can be hidden in.

The exposed rebar and mesh isn't about hiding it. It's about trying to get it sealed in concrete or mortar to limit air and water to keep it from rusting and busting your walls in the next 5 years.

 

[Waterbug]

Should I do a footing just at the bottom or all the way across the wall and take out the steps? . I hate to dig into the steps to much as they are really serving as some what support in the corners at this point. BUT I can also see that a wall all the way across would be the strongest.

Sorry, not enough info for me to know. Hopefully the general pictures above answered this.

I've told them I want 1/2" rebarb driven into the ground

Never pound rebar into the ground. No soil contact allowed.

then we can grind off the rebarb sticking out the top of the blocks once the wall is complete.

No. The rebar must be at least 1" below the top of the concrete and I would make it like 3" below. See rusting problem.

I'm thinking to fill the void between the block wall and the old wall and not taking it out. It's still got a good tight vertical bond and filling in between and tying the block wall into that wall should give more support against any future cave in on the waterfall side.

Not enough info for a specific answer, but when tying 2 wall together you have to drill holes into the current wall and anchor rebar into the holes either with epoxy or anchor cement. I like anchor cement, easier to work with. Drill the holes slightly downward so the anchor cement or epoxy stays in the hole.

we are going to be getting a cement truck out for the patio anyway tomorrow afternoon so if we can get most of the wall erected then we can fill the blocks

This would concern me. If your contractor is using a concrete vibrator then probably OK. Of if the walls are only 3' high, OK. If not I would not trust him to properly fill the voids. It takes experience to do this properly. Voids not only mean weak spots but also exposed rebar, rust and concrete failure. For the inexperienced I recommend mixing the concrete by hand and filling one course down as you go. Slower but better results for the inexperienced.

Since we are out away from the city we were not required by the parish to have one as long as we have a escape/steps and GFCI electrical which has already been installed and call it a watergarden. I can't go any deeper than 5' if I consider it a water garden or then it becomes a pool.

Just as a side conversation...here's what's odd about that to me...In most places if you're required to have say escape/steps that's code and would require a permit. Any electrical changes would require a permit and even a different inspector. Things that don't require a permit you can build however you like. So it's strange to me that a building department would say "you don't need a permit if you build it correctly". That's kind of the whole point to permits, to make sure it is built correctly. Just odd.

Hearing what I'm hearing makes me not want to ever buy property in LA. I wouldn't have much confidence in structures. We have a similar problem here in AZ. Here we have the code and permitting process but rules are not enforced. The big corporate builders run the state and can do pretty much anything they like.

 

[Waterbug]

A note on above grade pond structure design for general readers and for Larkin if any useful info can be had.

We have standard building practices to houses, office building, etc. We know exactly how to properly build a single story wood frame house. All the info needed is easy to find.

Ponds on the other hand are almost always custom deals. You generally can't find any source that can tell you exactly how thick a wall needs to be, etc., because each pond is different. A structural engineer could but would be expensive. So generally we take our best guess based on past experience. Not just our own past experience but the experience of others. Luckily we have lots of people willing to take the time to post their builds and the results, good, bad or in between. I sure wouldn't know half of what I do if it weren't for people posting their experiences.

Understanding a little bit about the forces involved can lead to better design guesstimates. Obviously an above grade wall wants to tip over. The why's aren't always so obvious.

Lot's of people focus only on the thickness of the wall. Important, but not really the main factor.

The red arrows show where soil pushes back. You can see the higher above grade the wall the more water force is unopposed. The more shallow the footer the less soil has to be pushed out of the way. That tells you the deeper the footer the harder it is for the water to push over the wall.

In the diagram the wall is half buried. The upper red arrow acts as a pivot point. 'B' shows almost all the force is in that one point. If the wall breaks it will right there at the red arrow. For this design we'd want the wall thicker than "normal".

But the most important thing is where we expect the break. If we were just dealing with a single straight wall 'B' would tell all. But a pond wall is a perimeter of course. The wall in 'B' can't tip over unless the corners break. And that is the most common failure. This is because at any one place along the wall there is a certain pressure, not really a lot. So given a reasonable thickness and rebar a wall is not going to break mid span. But all that force along the entire wall add up and get concentrated at the corners.

The longer the wall the greater the forces can be in the corners. That tells us the longer the wall the deeper we need the footer. Most people are going to say make the corners stronger. To make corners stronger they have to be curved. Taken to the maximum a round pond is strongest. Oval next strongest. Rectangular with rounded corners next. Square corners weakest. If we want square corners there's not much we can do to the corner themselves, so we reduce the pressure on them by making the footer deeper so the force along the entire wall is less.

Here is an example of a standard corner failure.

This pond was only 14' x 8'.

The blocks weren't oriented correctly, the bottom block on the left should have been oriented like the top. Each course should be oriented opposite, like interconnecting fingers.

Regular blocks were used instead of bond beam. Bond beam allows for proper rebar placement and a larger void for the poured concrete.

No rebar. Corners should have rebar every course.

Voids not filled with concrete. Many people think concrete block is mortared together to make a strong wall. Not really true. The mortar adds a little strength, but not much. The purpose of the mortar has always been to level out irregular shaped blocks. Modern manufacturing solved that problem. So now it's common to dry stack block and either put a skim coat over the wall to replace the little strength mortar joints provided or fill the voids with concrete so the result is basically a solid concrete wall. For above grade pond walls it's kind of important to fill the voids with concrete.

The above example is how many DIY above grade ponds are built. This pond was fixed by basically building a welded steel pond around the current pond. Expensive.

 

[fishin4cars]

Rebar
I don't have enough info to understand the patio tie in so I'll make some general comments...

I don't think the patio should be tied into the pond wall. I'm not sure on code, but I'd bet it wouldn't be allowed. Concrete patios can't be tied into a house foundation. And certainly at this point you wouldn't want to tie what could be a properly built patio to the incorrectly built pond wall. The risk is the pond wall might only last 1, 5, 10, 20 years. Tying into the patio means it would probably fail right along with the pond wall. Instead there should be an expansion joint between the pond wall and patio. Personally, I like something like a 1" gap between the two which I plant flowers or flag stone over. I like the gap because I'll probably want to run sprinkler pipe or electric there someday. Always seems to work that way.

It's a rookie mistake to think tying the patio and wall together adds strength. Proper building means each structure is stable on it's own. Rookies seem to understand they aren't building correctly and like to "add strength" but they're actually making things worst. I've done the rookie mistakes too.

As a side note on rookie mistakes...when the patio is built you sure do some research on whether wire mesh should be used. Ask the building department. I've seen local codes change over the last 30 years from requiring mesh to prohibiting mesh. The thinking is that for the cost of the mesh the slab can be made a little thicker and therefore strong enough without the mesh. That eliminates the rust risk and also greatly reduces removal costs and patio are remodeled often. Your contractor seems mesh happy.

This is the one thing I missed in the reading and didn't catch in time. and yes it was done, tied the patio directly into the pond wall. makes complete sense the way you explained it but I must have missed it while I was reading through. all the rebarb was cut off and covered with a minimum of 1/2" of mortar. Only one piece was 1/2" as it was already incased in cement and that was at a high spot so I grinded it off and covered with just enough motar to level the walls. that's just going to be a shelf for the liner to sit on and then a cap is going on top so hopefully it wont rust under ther as it will be ver limited moisture in that area.
We filled each run in the drystack wall with hand mixed cement and then vibrated each run. also filled behind the wall the next day and vibrated it down as well. we had extra cement on the truck ofter the second truck so decided to go ahead and fill that void in as I really need some good support ther for some water fall rocks as well. All in all It's looking better. BY FAR, NOT what I invisioned and I am still disappointed that I wasn't able to locate a professional to help in this project.

 

[Waterbug]

Looks good. When the water, fish and plants are in all of this will be forgotten.