Buried Concrete Behind my Pool Decking?

[ArtP]

I'm looking for someone knowledgeable about pool construction to chime in here. I know a bit, and I'm fairly confident I know the answer here, but I just want some reassurance from someone who actually knows....

Could this buried concrete be related to my pool at all? It's a few feet behind my decking, on the side opposite of all my equipment. I'm digging holes to plant banana trees and ran into this concrete. It's clearly poured, and pretty nicely done, too. My guess is that it's some kind of patio or something left over from before the pool was dug (25-ish years ago).

In the previous hole, I ran into some thin, poorly poured concrete with lots of large stones in it. I figured that was probably overpour or extra shotcrete from when the pool or decking were built, since it was mostly under an inch thick and my shovel went through it fairly easily. Then, working on the next hole, I found this big concrete slab.

Edited to add: The decking at the top of the photo is two steps higher than the decking around the pool - it's an elevated deck thing. The buried concrete is somewhere in elevation between that and the decking that actually surrounds the pool.

 

[Bperry]

I'm looking for someone knowledgeable about pool construction to chime in here. I know a bit, and I'm fairly confident I know the answer here, but I just want some reassurance from someone who actually knows....

Could this buried concrete be related to my pool at all? It's a few feet behind my decking, on the side opposite of all my equipment. I'm digging holes to plant banana trees and ran into this concrete. It's clearly poured, and pretty nicely done, too. My guess is that it's some kind of patio or something left over from before the pool was dug (25-ish years ago).

In the previous hole, I ran into some thin, poorly poured concrete with lots of large stones in it. I figured that was probably overpour or extra shotcrete from when the pool or decking were built, since it was mostly under an inch thick and my shovel went through it fairly easily. Then, working on the next hole, I found this big concrete slab.

Edited to add: The decking at the top of the photo is two steps higher than the decking around the pool - it's an elevated deck thing. The buried concrete is somewhere in elevation between that and the decking that actually surrounds the pool.
View attachment 561828

Maybe some steps up to the pool?

 

[ArtP]

I think it must be older than the pool, but I'm really not sure. There are steps on either side of the higher part of the decking. Also this is between my pool and the edge of my property, opposite from the house and the pool gate. I guess what I really am trying to figure out is: there's no reason there would be buried, poured concrete several feet behind my pool that is somehow integral to my pool, right? Like I said, I know it's not part of the pool, but some part of me feels unsure and I wanted someone who knows more to reassure me.

 

[Newdude]

there's no reason there would be buried, poured concrete several feet behind my pool that is somehow integral to my pool, right

Correct. It has nothing to do with the pool.

It really looks like a step IMO. Dig back to the patio to find out. If it doesn't go all the way, they buried chunks of the old patio (etc) instead of removing them.

 

[ArtP]

Thank you. I knew that when I saw it, but I always second guess myself...
There's nothing behind it, away from the pool, except my cinderblock wall and property line. The other direction, my pool is in the way. I don't know what was out there before they dug the pool - maybe a patio or something. But it would have been pretty far from the house so it just seems like a weird location. Anyway, I'll continue with planting my bananas.

 

[Bperry]

Thank you. I knew that when I saw it, but I always second guess myself...
There's nothing behind it, away from the pool, except my cinderblock wall and property line. The other direction, my pool is in the way. I don't know what was out there before they dug the pool - maybe a patio or something. But it would have been pretty far from the house so it just seems like a weird location. Anyway, I'll continue with planting my bananas.

Curiosity would get the best of me and I’d want to dig more of it out like an archeologist.

 

[Newdude]

Curiosity would get the best of me and I’d want to dig more of it out like an archeologist.

Not knowing is bothering me from across the country. if it was mine all plans would be cancelled. Sleep too.

 

[Newdude]

What about a cesspool or drywell ? I needed a drywell per code for draining/backwashing.

Originally I was seeing a step up to the patio but the circles don't line up. Now I'm seeing a concrete lid.

 

[kul]

Same. I just have to know what the heck it might be. I would not be able to focus until I at least spent some more time digging like a maniac.

 

[JamesW]

It definitely seems suspicious to me.

 

[ArtP]

Hahaha well at least I'm not the only one who was really curious!

Curiosity would get the best of me and I’d want to dig more of it out like an archeologist.

It got the best of me too!

What about a cesspool or drywell ? I needed a drywell per code for draining/backwashing.

Originally I was seeing a step up to the patio but the circles don't line up. Now I'm seeing a concrete lid.

My mom suggested an old concrete septic tank, and I know some houses in my neighborhood had or still have septic tanks (not mine, though). But I would have expected that to be rectangular, and this clearly had some curvature.

Same. I just have to know what the heck it might be. I would not be able to focus until I at least spent some more time digging like a maniac.

I spent too much time standing by the hole, staring at it, and deliberating whether to dig it up more or just get my dang bananas planted. I eventually settled on doing some more digging (I got my banana trees planted as well).

Here are some pictures I took after excavating it a little more.

This is taken from the side toward my pool. I can see that the first concrete piece I found was painted white, and is scalloped on one side. There are some kind of pavers or something beyond that.


On this side, there's another concrete piece that has a similar curve to the outside piece.


The back where I originally encountered it is about 14-16 inches tall.


My best guess currently is that it's an old fire pit or seating area around a fire pit. Behind the outer part of it, I found some old charred wood, and dug up some 2003 vintage Bud Light bottles as well.


Now I'm back to debating with myself... do I really want to keep digging up my pool area?

 

[kul]

Hmmm the charred wood and beer bottles do seem to indicate a possible fire pit. If you’re comfortable with this conclusion, then you can stop digging. If you continue, I’m still going to pay attention to this thread.

 

[ArtP]

I might pick it up again some time, but I ran out of steam today. I can't go much further forward because I'll run into the pool decking. I might continue along the curve of the outer part just to see if I can find any more interesting features. If I do, I'll come back and post pictures here!

 

[ArtP]

Hmmm the charred wood and beer bottles do seem to indicate a possible fire pit. If you’re comfortable with this conclusion, then you can stop digging. If you continue, I’m still going to pay attention to this thread.

The only thing is, the charred wood was behind, or outside, of the "thing". But it's possible they were just throwing stuff that way when they cleaned up after having a fire. The beer bottles might also be from the pool builder's crew... Who knows??

 

[Homebrewale]

Are you sure it's not an old burial ground like in Poltergeist?

 

[kul]

Are you sure it's not an old burial ground like in Poltergeist?

Abort the mission! Yikes!

 

[ArtP]

Are you sure it's not an old burial ground like in Poltergeist?

Pretty sure. But I've also never seen that movie, so I'm not afraid!