Hello from Omaha, NE! screening sub-base for AGP?

[cmjewell1123]

Hello and thank you for all the great advice i have found thus far. It is truly a treasure trove of Pool knowledge. We are putting in an 18' x 33' AGP, and after spending days digging into the hill to get down to level, it is now time to prep the ground for the pool install.

One thing I can't find much information on is using 1/4" limestone screening as a sub base for the pool. I'm told that when it is compacted, it is practically concrete but provides good drainage as well. Since we have about a 2 and 1/2 foot drop in elevation from the high side of our yard to the low side, after digging everything out our clay soil is rock hard. I am using a rotary laser level to check level and everything is within an inch. I'm hoping the limestone screening will allow me to level the area properly since the clay is so difficult to work with.

Has anybody ever used an aggregate sub base for their above ground pool? If so, how deep of aggregate? tips for placing/leveling 12" x 12" patio stones? any words of caution?

I was I was thinking of setting the pavers before compacting and just compacting them with everything else. as opposed to compacting everything and then trying to chip away at the screening to get the pavers set level with the screening.

I will be using a plate compactor on the screenings and sand.

Thanks for the help!

 

[Caco]

Hi Cmjewell1123 and welcome to the forum
I haven't dealt with limestone in a while and use much bigger gear than a plate compactor for works but heres some general tips that may help
Make sure your limestone goes under your pavers as well as around them. You do not want the base under the pavers to potentially be softer than the rest of the pool. But yes you can place the pavers on the limestone and then compact them when you get to that level. Make sure to cover them with sand before you run the compactor over them, less chance of breaking/chipping the pavers and easier on the machinery
Make sure your limestone has plenty of broken faces, at least three. The smoother and rounder stones wont pack down and continually shift
Make sure any water that potentially runs down the slope and towards the pool and the base you are creating is caught and directed away from the pool, so it doesn't create wet areas that will soften and slump. This could be done with a subsoil drain coil that is buried.
Do the limestone in multiple lifts. The plate compactor will not be able to deeply compact. Not sure how much height you could get away with at one time, ask the people where you source the limestone for their advice on this as well as where you are getting the compactor from
When compacting you need some moisture in the material for it to compact well, known as its optimum moisture content, maybe 8%. From memory very little with limestone. Again ask your supplier but unlikely to be a problem unless it is really dry where you are
Compact the subbase before you place the limestone on top. If you are worried that the limestone ship may sink into the ground beneath you could roll out weedmat as a barrier between the subbase and the limestone
The limestone and clay will react and form a really hard good interface if the clay is hard enough to compact on
When you have your first 'lift' of limestone spread and ready to compact always start by going around the edges and working in with a spiral. Make several passes of the material in various directions after that and you will hear and feel when it is compacted. The sound will change and it will feel like the compactor is bouncing more
Dont be afraid to ask questions of your local material and machinery suppliers that you are using. They know your local materials best and how to get the best from them

Oh and since it is limestone I would wear coveralls and a breathing mask and ensure to shower off well soon after finishing work. Limestone can be nasty to skin and breathing the dust into your lungs is certainly not a good idea

Lots of luck