Need Advice: Backyard Soil is Sandy with Clay Underneath What Do I Do for Above Ground Pool?

buddy732

New member
May 19, 2025
4
NJ
I’m getting ready to set up an above ground pool in my backyard, but I’m not sure how to prep the ground properly. The top layer is soft, loose sand and underneath that is a firmer orangish clay-like material.





What’s the best way to build a stable base in this kind of soil? I want to make sure the pool doesn’t shift or sink over time. Appreciate any advice from people who’ve dealt with similar ground conditions.

 
Nope, you cannot compact fill sufficiently to withstand settling of the water weight.

If you are on a lot that was graded and filled by a builder you will have difficulty finding undisturbed soil that will not settle.
 
Gotcha, so what should I do?
Do the best you can with the setup and not be surprised if the pool settles and you need to break it down and level it every year or two.

You may not have good land for a stable pool.
 
Do the best you can with the setup and not be surprised if the pool settles and you need to break it down and level it every year or two.

You may not have good land for a stable pool.
Thanks for the reply I guess it is what it is for this type of soil. Thoughts on the instructions below




Above Ground Pool Base — Final Step-by-Step Guide











TOOLS & MATERIALS








  • Tools: shovel, landscaping rake, 10 ft 2x4 with level, plate compactor (rent), hose
  • Materials: crusher dust (4–6 in), 14 pavers (12x12), geotextile fabric (optional), masonry sand or foam pad (1–2 in)
















STEP-BY-STEP INSTRUCTIONS











1. Mark and Clear the Area








  • Mark an 18 ft diameter circle.
  • Remove all grass, roots, sticks, and soft topsoil (about 2–4 in).
















2. Dig Down to Firm Soil (~6 in)








  • Dig until you hit firm, compactable soil — often about 6 inches deep.
  • Confirm with jump test (heel doesn’t sink) and stab test (resists screwdriver).
  • STOP digging once soil is firm.
















3. Level the Whole Area to That Depth








  • Use your 2x4 and level.
  • Spin it around the circle like a clock hand.
  • Scrape down high spots to match the lowest firm point.
















4. Compact the Exposed Soil








  • Lightly mist the soil.
  • Compact the entire area with a plate compactor.
  • Do overlapping passes.
  • This is your subgrade.
















5. (Optional) Add Geotextile








  • If your compacted soil is still sandy/loose, lay woven geotextile fabric over the whole circle to stabilize.
















6. Build the Crusher Dust Base








  • Spread 2 inches of crusher dust.
  • Use 2x4 + level to get it flat and level.
  • Lightly mist, then compact.
  • Repeat steps:
    • Add 2 in,
    • Level,
    • Mist,
    • Compact.

  • Build up to 4–6 in total thickness.
















7. Set the Pavers for Pool Legs








  • Mark where the 14 legs will go.
  • Dig out spots so the pavers sit flush with the top of your crusher dust base.
  • Use a bit of crusher dust underneath each to level them.
  • Check each one for level.
















8. Add Cushion Layer








  • Spread 1–2 inches of masonry sand or lay foam pad.
  • This cushions the liner.
  • Do not compact this layer.
















9. Assemble the Pool








  • Place the liner and frame.
  • Each leg should sit centered on a paver.
  • Confirm everything is level before adding water.
















10. Fill Slowly and Monitor








  • Fill the pool a few inches at a time.
  • Check for movement or settling.
  • Adjust before continuing.
















11. (Optional) Add Gravel Ring








  • Once full, add a 6–8 in wide gravel ring around the pool edge to control splash-out and erosion.



Pool Wall + Liner
||
[ Cushion ]
(1–2 in sand or foam)
=========================
Compacted Crusher Dust
(4–6 in in 2 in lifts, level)
=========================
[Geotextile Fabric Layer] ← optional, if soil is sandy/loose
-------------------------
Compacted Firm Soil
-------------------------
Undisturbed Subsoil