Depth Conversion Remodel

[Chrisj88]

Hi all,

I'm shallowing out my +20K gallon kidney shaped pool. The pool has an open stress crack at the outer bend and has been empty for a couple years aging several additional cracks throughout. The PB will be opening and repairing cracks as needed once the plaster is off and they get a better look at the shell.

The whole bottom from shallow to deep will be rebarred and shotcreted and blended into the walls.
My concern is this:
The deep end will go from 9' to 5'6".
The shallow end will go from 3" up to a 6" sun shelf from wall to wall extending about 8' into the pool. From sun shelf to deep end there will be roughly 12"cover sloping down to the 5'6". There will be a tremendous weight in the shallow and in the deep end from the amount of shotcrete. Will this make for a weak STRESS joint in the middle around the kidney turn?? PB says not to worry.

As added strength I'm adding a seat bench completely around the outer bend of the kidney.

Should all rebar be 9" grid?

I recognize I'll get responses to consult an SEOR but just wanted some experience in here first.
I'm a couple weeks away from the build and could use any thoughts sooner than later.

Many, many thanks!

 

[kimkats]

Hi and welcome to TFP!! Nice to meet you!

I am going to ask you some questions to get into your head about your whys and wants:

- the deep end at 5'6" Why did you come up with that depth?

-I am guessing you mean 3' (feet) where it says 3" for your shallow end (I don't want to guess wrong and I can fix anything in your post to help it read better). Is this the depth the shallow is now?

-12" cover sloping down-I am thinking you mean 12' to slop from the 3' shallow end to the 5'6" deep end.

-Do you already have a shelf in the pool? Why do you want one?
-I want you to sit on the floor and see where 6" hits you on your body. That is not much coverage at all. On my it would not even cover my lap. When I sit in water I like the water come come up to the middle of my chest. For me that would be 20" or so.

I look forward to you sharing your ideas so we can make sure you have the best pool for your wants and needs!!

Kim

 

[Chrisj88]

- the deep end at 5'6" Why did you come up with that depth? It's the deepest I could go meeting the code slope pitch limitation (forgot what that is). 8' of sun shelf, then drop off to 3' sloping down to 5'6".

 -I am guessing you mean 3' (feet) where it says 3" for your shallow end (I don't want to guess wrong and I can fix anything in your post to help it read better). Is this the depth the shallow is now? Correct.

-12" cover sloping down-I am thinking you mean 12' to slop from the 3' shallow end to the 5'6" deep end. I poorly worded this. I'll have a depth conversion shotcrete fill for a sun shelf (out 8' from the end of the pool, then about 12" of shotcrete fill in the middle at its thinnest points and thickening down the slope to the shotcrete fill of up to 3' to 4' in the deep end.

-Do you already have a shelf in the pool? No
Why do you want one? To make our pool more functional. Having less water means less maintainence, chemicals, easier to heat, increasing the pool season, and having the pool generally more manageable.
-I want you to sit on the floor and see where 6" hits you on your body. That is not much coverage at all. On my it would not even cover my lap. When I sit in water I like the water come come up to the middle of my chest. For me that would be 20" or so. This is a way to be in the water and not "be in the water" for sunning and what not. Is meant for lounge chairs. It will create heating location for the water as well.

I'm originally from Florida and Ca has more challenges as a pool climate. Evaporation, cold nights, less summer rain, higher energy and chemical costs, come to mind.

Thanks for your input and help.

 

[Chrisj88]

- the deep end at 5'6" Why did you come up with that depth? It's the deepest I could go meeting the code slope pitch limitation (forgot what that is). 8' of sun shelf, then drop off to 3' sloping down to 5'6".

 -I am guessing you mean 3' (feet) where it says 3" for your shallow end (I don't want to guess wrong and I can fix anything in your post to help it read better). Is this the depth the shallow is now? Correct.

-12" cover sloping down-I am thinking you mean 12' to slop from the 3' shallow end to the 5'6" deep end. I poorly worded this. I'll have a depth conversion shotcrete fill for a sun shelf (out 8' from the end of the pool, then about 12" of shotcrete fill in the middle at its thinnest points and thickening down the slope to the shotcrete fill of up to 3' to 4' in the deep end.

-Do you already have a shelf in the pool? No
Why do you want one? To make our pool more functional. Having less water means less maintainence, chemicals, easier to heat, increasing the pool season, and having the pool generally more manageable.
-I want you to sit on the floor and see where 6" hits you on your body. That is not much coverage at all. On my it would not even cover my lap. When I sit in water I like the water come come up to the middle of my chest. For me that would be 20" or so. This is a way to be in the water and not "be in the water" for sunning and what not. Is meant for lounge chairs. It will create heating location for the water as well.

I'm originally from Florida and Ca has more challenges as a pool climate. Evaporation, cold nights, less summer rain, higher energy and chemical costs, come to mind.

Thanks for your input and help.

The attachment may help. There are some changes to it. The outer edge bench will wrap around and deadend past the outer stair to give strength to the crack currently at that location. The 9" shelf will be 6".

 

[Bperry]

The attachment may help. There are some changes to it. The outer edge bench will wrap around and deadend past the outer stair to give strength to the crack currently at that location. The 9" shelf will be 6".

I don’t have any opinion on the overall design except that adding in extra features to fix a crack probably isnt going to turn out well. Cracked shells are caused by moving compromised soil underneath them. You need to fix the cause of the crack before expecting any repairs to hold. If the cause of the crack was a water leak, and the pool has been dry for a while then it may be fine to patch it up and replaster. But if there was a plumbing leak underground that isn’t repaired, it’s just going to crack again.

 

[AQUA~HOLICS]

Is the PB obtaining steel engineering plans for the work to be performed?
Cause of the “stress crack” must be fully understood and then corrected before any other work can be started.
Feathering in Shotcrete is not the proper procedure, a minimum thickness must be applied that meets the existing shell, also the prep work prior to application is vital for the work to have a long lasting strength.

 

[Chrisj88]

The deeper story: The outer edge is about 5-6' from fencing line on the shallow end side. This is also about a 3' wood retaining wall which has had some reinforcement on the back side. The original deck built with the pool in '76 was cantilevered to the pool. Back in '99 I removed a huge amount of that CA green ivy and replaced the fence. The large root structures rotted, along with soil settlement created a void contributing to a hairline crack. I'm '08 I replaced the deck with a coping separation, checking all the plumbing return lines, adding French drain and rock and compaction. I had a fiberglass shell sprayed. Fast forward 10 yrs, I removed the fiber shell and found the hairline crack was now fairly open.
I've found the shallow outer corner sits about 1/2" lower than the rest of the pool.
I've been toying the idea of more reinforcement to the wall with slurry. This is becoming a clearer path now. The PB has given me a couple Engineers to consult.
Thanks for leading me to what should have been common sense

But all things being equal with ground conditions, is it normal to have a block of shotcrete filling the deep end and a block of concrete filling the shallow end? Or is it better means and methods to cut the bottoms out, gravel, then pour the shotcrete to alleviate the weight in the ends?

 

[Chrisj88]

Hello, I've consulted with a pool structural engineer and he's reviewing my project. Thought I'd supplement this with more pool building experience here.
When shallowing the pool is it recommended to pothole below the shotcrete to minimize hydrostatic pressure in the event water gets between the shells? Would this be a series of 2" cord holes? One large hole in the existing shell, or not recommended or needed?
Thank you!