Design flaw on my new negative edge pool

[hgurusamy]

Hi,

I am new here and am hoping that someone can share some information regarding an issue I am having. We had a negative edge pool built recently and right next to it is a sunken firepit lounge. The way that it was designed, whenever we use the pool, the water flows right out of the pool into the deck all around the pool and and into the sunken lounge, getting my cushions all wet and making part of the space unusable. My contractor didn't feel like finishing the job (I paid him in full and he just abandoned the project without finishing) and I cannot get him to come back so now I have this issue with the pool.... Someone told me that there is a way to lower the water level in the pool while using it and drain the water into the water tank so that the water won't flow out of the pool - has anyone heard of this?

Thank you so much for any info...

-Helena

 

[kimkats]

Well that sure does not sound like a good thing How about a pic of this pool and the firepit? That will help us really know what you are dealing with.

 

[AQUA~HOLICS]

H, is the water flowing out of the pool and into the catch basin and the catch basin over flowing? Is this whats happening or is the pool itself overflowing when being used?

 

[hgurusamy]

Well that sure does not sound like a good thing How about a pic of this pool and the firepit? That will help us really know what you are dealing with.

Hi,

the photos I have are too large to attach but I will try to save a lower resolution and post it. Thanks.

 

[hgurusamy]

H, is the water flowing out of the pool and into the catch basin and the catch basin over flowing? Is this whats happening or is the pool itself overflowing when being used?

Hi,

some water flows into the catch basin and some of it overflows out of the pool, past the gutter and into the sunken lounge.

I will try to post some photos shortly. Thank you.

 

[hgurusamy]

Managed to get some images to upload. The area circled in red on second photos is where the water flows out of the pool and into the sunken lounge (photo one is the close up).

Thanks.

 

[JamesW]

It looks like a perimeter overflow rather than a vanishing edge.

It's a similar effect, but a little bit different.

Typically, you have a pump pulling from the reservoir and pushing into the pool which creates a circulation.

It's a very difficult design to get exactly right.

Can you show the filter and pump equipment?

Is the edge pump on when people are in the pool?

 

[kimkats]

So there is a small gap between the tile and deck where the water is supposed to go? I have an idea but want to make sure I am seeing it right.

 

[setsailsoon]

Helena,
Welcome to TFP. Wow, gorgeous pool! My new pool design is very similar but I don't have the sunken fire pit next to the pool as you do. As James points out the hydraulics are tricky. You have to make assumptions about how many people will enter the pool and design such that water displacement can be managed by the perimeter drain system including the holding basin and pumps. In my design the pump (s) will increase in capacity as the basin fills. The perimeter drain will be sized such that it can drain maximum capacity of the pool water displaced when people get in. This is more difficult than you may think since people get in very quickly so the immediate flow rate is very high for a very short time. Also when people get in there is an immediate increase in pool water level that happens closer to the person getting in and a "wave" propagates around the pool eventually so the area closest to the person gets higher water flow first. The gap in yours looks pretty small. Do you have any design drawings showing pipe sizes? If the problem is just pump size that's easier to fix but It appears your perimeter drain system is under-sized and/or the tank and pump system are under-sized or both. Fixing this could be expensive and the most practical solution may be to build the concrete up between the pool and sunken pit. But that's going to result in more overflow around the rest of the pool. It looks to me you have water that is over-flowing all around the pool as it is that is not being captured by the perimeter drain system.

Wish I had better news. More photos of the entire pool, drain basin or tank, pumps, piping and drawings if possible would help our experts analyze the problem. Maybe one of them can come up with a simple solution.

Chris

 

[AQUA~HOLICS]

The pool requires a perimeter drain around the pool decking typically just behind the coping. Common on indoor commercial pools where the deck is needed to be as dry as possible for safety reasons. Your deck could have had a greater fall towards the drains and more of them.

 

[setsailsoon]

Helena,

See the sketch below. There are several key parameters that must be correctly designed for a perimeter drain system (this sketch shows one of several proven methods)?

• The gap between the coping and the surround.
• Size and slope of the buried perimeter drain pipe.
• Vent of the drain pipe.
• Access for cleaning.

There are several ways to accomplish this and unfortunately some PB's underestimate the more complicated design that's required so they learn the hard way. My guess is that one or more of the items above is not designed correctly. On many pools this wouldn't be as big a problem since you would just lose more water than you should with water over-flowing the outer edge. But in your design with the close sunken fire pit the problem is more evident. If it were me I'd ask the PB to come over a look at the pool while people get in. Then ask him if he's built a pool like this before and had this problem. Your objective of this conversation is to get him to recognize the problem then you can get him to commit to a modification to address it. If you can't get him to do this then you'll have to bring in another PB and try to collect in small claims court at least a portion of your cost. The only other option that I see is do nothing and live with 3 walls in your sunken pit. Does the pit floor drain adequately?

Chris

 

[ccbill]

• The gap between the coping and the surround.

I didn't even know what perimeter overflow was till I read this post. After looking at a lot of stuff online, it seems that the gap/opening to the gutter is typically spec'd at 1 inch. While that may be enough to handle normal quiescent flow, I don't see how it could ever capture waves of water splashing over it from enthusiastic swimmers - unless the coping/cover is porous or has holes/slits, most all the designs I saw don't allow for this. Seems like with use there would always be some overflow. Am I missing something?

 

[setsailsoon]

I didn't even know what perimeter overflow was till I read this post. After looking at a lot of stuff online, it seems that the gap/opening to the gutter is typically spec'd at 1 inch. While that may be enough to handle normal quiescent flow, I don't see how it could ever capture waves of water splashing over it from enthusiastic swimmers - unless the coping/cover is porous or has holes/slits, most all the designs I saw don't allow for this. Seems like with use there would always be some overflow. Am I missing something?

Well sort of. The gap is immediately between the pool edge and the surround material the first 12 inches or so is sloped at 2% back towards the gap. You can see that in the sketch I attached. Two designers I've spoken with recommend 2" though. These pool designs are not so common that "rules of thumb" like a certain size gap can be relied on. It really takes a qualified designer to do the calcs. This goes for the whole system. It appears to me there are several different approaches that work fine including using a much simpler over-sized pipe under the gap. Don't under estimate the importance of the vent also. This is required to drain and to prevent gurgling noises.

Chris

 

[hgurusamy]

It looks like a perimeter overflow rather than a vanishing edge.

It's a similar effect, but a little bit different.

Typically, you have a pump pulling from the reservoir and pushing into the pool which creates a circulation.

It's a very difficult design to get exactly right.

Can you show the filter and pump equipment?

Is the edge pump on when people are in the pool?

HI,

so sorry for the delay in responding to your post. I have taken photos of the pump equipment. The edge pump is usually on when people are in the pool although I have tried turning it off and the water still overflows. Thank you.

 

[hgurusamy]

So there is a small gap between the tile and deck where the water is supposed to go? I have an idea but want to make sure I am seeing it right.

Yes - you can see it better on the attached picture.

Thanks.

 

[hgurusamy]

Helena,
Welcome to TFP. Wow, gorgeous pool! My new pool design is very similar but I don't have the sunken fire pit next to the pool as you do. As James points out the hydraulics are tricky. You have to make assumptions about how many people will enter the pool and design such that water displacement can be managed by the perimeter drain system including the holding basin and pumps. In my design the pump (s) will increase in capacity as the basin fills. The perimeter drain will be sized such that it can drain maximum capacity of the pool water displaced when people get in. This is more difficult than you may think since people get in very quickly so the immediate flow rate is very high for a very short time. Also when people get in there is an immediate increase in pool water level that happens closer to the person getting in and a "wave" propagates around the pool eventually so the area closest to the person gets higher water flow first. The gap in yours looks pretty small. Do you have any design drawings showing pipe sizes? If the problem is just pump size that's easier to fix but It appears your perimeter drain system is under-sized and/or the tank and pump system are under-sized or both. Fixing this could be expensive and the most practical solution may be to build the concrete up between the pool and sunken pit. But that's going to result in more overflow around the rest of the pool. It looks to me you have water that is over-flowing all around the pool as it is that is not being captured by the perimeter drain system.

Wish I had better news. More photos of the entire pool, drain basin or tank, pumps, piping and drawings if possible would help our experts analyze the problem. Maybe one of them can come up with a simple solution.

Chris

Hi Chris - thank you, the design does look pretty nice but it just doesn't work...

I am attaching some photos I took when they were building the pool (I may have more, will forward when I find them) - unfortunately, the PB abandoned the project and left me with no drawings so I have no idea how it was built...

Thank you.

 

[hgurusamy]

Helena,

See the sketch below. There are several key parameters that must be correctly designed for a perimeter drain system (this sketch shows one of several proven methods)?

• The gap between the coping and the surround.
• Size and slope of the buried perimeter drain pipe.
• Vent of the drain pipe.
• Access for cleaning.

There are several ways to accomplish this and unfortunately some PB's underestimate the more complicated design that's required so they learn the hard way. My guess is that one or more of the items above is not designed correctly. On many pools this wouldn't be as big a problem since you would just lose more water than you should with water over-flowing the outer edge. But in your design with the close sunken fire pit the problem is more evident. If it were me I'd ask the PB to come over a look at the pool while people get in. Then ask him if he's built a pool like this before and had this problem. Your objective of this conversation is to get him to recognize the problem then you can get him to commit to a modification to address it. If you can't get him to do this then you'll have to bring in another PB and try to collect in small claims court at least a portion of your cost. The only other option that I see is do nothing and live with 3 walls in your sunken pit. Does the pit floor drain adequately?

Chris

View attachment 382643

Unfortunately, my PB has abandoned the project and will not talk to me at all. I have hired a lawyer and he is not even responding to the lawyer - it is truly despicable what he is doing and I am trying to find a way to get him to pay for what he has done in this project. He actually had the nerve to send me a message a few months back stating that once he realized that he was not going to make any money on this project, he really doesn't care anymore.... he got in over his head - he didn't know what he was doing, it was like getting a carpenter to perform brain surgery... Anyway, I am trying to get someone that knows how to fix it to come and have a look but nobody is interested in even talking to me, everyone is very busy and making lots of money so this is not interesting enough for them. I appreciate you sharing this information, thank you.

 

[hgurusamy]

Well sort of. The gap is immediately between the pool edge and the surround material the first 12 inches or so is sloped at 2% back towards the gap. You can see that in the sketch I attached. Two designers I've spoken with recommend 2" though. These pool designs are not so common that "rules of thumb" like a certain size gap can be relied on. It really takes a qualified designer to do the calcs. This goes for the whole system. It appears to me there are several different approaches that work fine including using a much simpler over-sized pipe under the gap. Don't under estimate the importance of the vent also. This is required to drain and to prevent gurgling noises.

Chris

I get a lot of gurgling noises even when nobody is in the pool and when I look down the gutter, I see water pooling in there, doesn't look like it is properly draining. I am also not sure where there should be a slope? I don't see a slope anywhere on the surround material on either side of the gutter....

Thanks.

 

[Charlie Bezzina]

Hgurusamy, a second linear drainage channel in the seam between the concrete coping and the concrete slab would catch most of the overflow. If you prefer not to see a wedgewire grate you can also get a narrow open top channel.

 

[kimkats]

So where do you think the water is supposed to go? Where in the build pic is the channel? The one that has the pipes showing is what I am looking at.