We purchased a used 24 ft round pool with steel sides. I was in the process of researching how to prep the ground for installation. My boyfriend had a friend come over and dig out the area for the pool. He actually dug 2 feet down due to the roots of the grass and weeds and filled the area with 2 feet of sand. The ground is level for the pool but it has a slope behind it. I’m worried the sand will wash away after the winter thaw and spring rain. What do we need to do to prevent this? I talked to an installer for suggestions and he said to dig a trench around the high end and fill with stone to help with drainage. I’m at a loss
Clay soil
- Thread starter Hheckman
- Start date
Selenap
Well-known member
Sand will wash out. Especially two feet of it being used to build the level back up. No amount of drainage is gonna stop it. The maximum should be 3-4 inches. Two feet is not stable at all. I would seriously suggest you dig down the high side to meet the low side. You must put this pool on virgin untouched soil. Then use the 3-4 inch sand buffer for the liner. You cannot compact 2 feet of sand hard enough to make this work. A 24 foot pool filled with water is an incredible amount of weight. I’m trying to scare you into not proceeding with it. It’s just too dangerous in my opinion. It’s one thing if it’s not in level by a few inches to fix it with sand but disaster awaits with what your describing. If someone can correct me on this by all means do, but I just don’t see how this will hold the pool up.
If done properly you can most certainly can backfill and compact 2 feet of the proper soil. NOT SAND.
I've seen it done first hand.
In that case he added a few inches and compacted, few more inches, compacted etc. It was very time consuming and requires specific soil.
I've seen it done first hand.
In that case he added a few inches and compacted, few more inches, compacted etc. It was very time consuming and requires specific soil.
Ugh! Okay. Looks like I will have to get the shovel out and start clearing out some sand. After I told the boyfriend it was too much sand he threw in the towel and told me to find someone to install it. We live an hour and a half from any cities that have installers. Thanks for the advice!
All non-organic soils can be compacted. Organic soils rot, so they are right out.
Here is the thing about soils. It is not about spraying them with a hose, and "packing them real good". Soils have a maximum dry density, where they will not compact (settle) any further. Every soil has a different maximum dry density. They only way to know this value, is to test it - normally with a standard proctor test. It is not a hard test to perform, nor does it require a lot of fancy equipment (I have performed 100's of them in the field). Then you have to know if you have compacted it enough. To do that, you need to calculate moisture/density curves for the soil, make sure your soil moisture is within the correct range, compact it, and then test the compacted soil - either with an Ottawa Sand Cone or a Nuclear Soil Densometer. You can buy a sand cone, you are not buying (or transporting) a densometer. Then if you have loose, non-cohesive, soil it can wash out. I could get into how to calculate slope stability of both a free standing soil and a soil with vertical loading, but that is not necessary. I just highly doubt that anybody who puts fill for a pool on a grade cut is running those calculations either.
The moral of all of this is, the average homeowner (or for that matter contractor with a bobcat and plate compactor) does not have the knowledge or resources to know if they have compacted any fill enough. With a pool weighing multiple tons on top of it, any soil that is not compacted enough will eventually settle - with disastrous results. This is why it is recommended to not use any fill. What is there already has had plenty of time, moisture, and surcharge on it to compact on its own.
Here is the thing about soils. It is not about spraying them with a hose, and "packing them real good". Soils have a maximum dry density, where they will not compact (settle) any further. Every soil has a different maximum dry density. They only way to know this value, is to test it - normally with a standard proctor test. It is not a hard test to perform, nor does it require a lot of fancy equipment (I have performed 100's of them in the field). Then you have to know if you have compacted it enough. To do that, you need to calculate moisture/density curves for the soil, make sure your soil moisture is within the correct range, compact it, and then test the compacted soil - either with an Ottawa Sand Cone or a Nuclear Soil Densometer. You can buy a sand cone, you are not buying (or transporting) a densometer. Then if you have loose, non-cohesive, soil it can wash out. I could get into how to calculate slope stability of both a free standing soil and a soil with vertical loading, but that is not necessary. I just highly doubt that anybody who puts fill for a pool on a grade cut is running those calculations either.
The moral of all of this is, the average homeowner (or for that matter contractor with a bobcat and plate compactor) does not have the knowledge or resources to know if they have compacted any fill enough. With a pool weighing multiple tons on top of it, any soil that is not compacted enough will eventually settle - with disastrous results. This is why it is recommended to not use any fill. What is there already has had plenty of time, moisture, and surcharge on it to compact on its own.
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Ahh, Tawas. Spent a few summers near there. 
(I remember a lot of sand on the AuSable)
Do you know the make and model of the pool? Do you have/can you get your hands on the installation instructions?
This will take some time, up to a few weeks if you're doing it yourself and those instructions are very important for proper installation of a hard sided Above Ground Pool.
It can be done. We put ours up ourselves in 2007 and it took some time to do.
(I remember a lot of sand on the AuSable)Do you know the make and model of the pool? Do you have/can you get your hands on the installation instructions?
This will take some time, up to a few weeks if you're doing it yourself and those instructions are very important for proper installation of a hard sided Above Ground Pool.
It can be done. We put ours up ourselves in 2007 and it took some time to do.
I think there may be a misunderstanding. Did the friend dig a 2' deep hole and then re-fill with sand so it is completely contained by the surrounding soil like cereal in a bowl, or is the sand piled higher than the soil around it. If the sand is free to wash away at any point around the pool then it will. If the sand is contained by surrounding soil you should be ok. A picture would help greatly.
If you put the base rails and patio stones (doughboy has you use cinderblock under the main supports) on sand, even if it is in a "bowl" surrounded by dirt, the sand will shift and move, making the walls of the pool unstable. That scenario will also retain water and corrode the wall of the pool.
Selenap
Well-known member
I feel bad for being so dire but having that much weight on that much sand wether it’s in a bowl or mounded up would scare me to death. Putting any drainage in it, or even outside of the sand runs the risk of collapse, like creating a long skinny sink hole.
I have a sad for you. I agree a pic would be helpful. My gut is not saying good news but it might change after seeing a pic.