Design help

jimmythegreek

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Aug 10, 2017
2,626
Morris Cnty NJ
Looks good. I'm guessing they had issues removing old pool and that caused the huge overdig. Just be careful with that area, very hard to fill that in and not settle unless it's all stone backfill
 

jimmythegreek

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Aug 10, 2017
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Morris Cnty NJ
Makes no difference honestly. What does the wet sand do near the waters edge when you step on it? Theres no way to properly compact it. You doing concrete decking?
 

jimmythegreek

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Aug 10, 2017
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Morris Cnty NJ
My advice is to wait til next year to lay pavers. I cant tell you how many decks I've ripped out because of fill dirt in the overdig. It will look fine this year but after a winter you will have bird baths everywhere near pool
 

jimmythegreek

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Aug 10, 2017
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Morris Cnty NJ
Yup astro turf. Home cheap sells it on rolls I use it on every build and one of my laborers powereashes it for next site. Lasts a while too even in the sun
 

Rich D

Bronze Supporter
Aug 3, 2018
783
MA
Theres no way to properly compact it.
Actually sand is one of the better soils for compaction when done properly. It would be my choice of backfill material if 3/4 clean stone was not available. The issue with using any soil that requires compaction to backfill a liner pool is it is impossible to get mechanical compaction around all of the supports. Flood settling is a accepted practice but needs to be done with the correct material and in stalled in lifts just like mechanical compaction. So you would need to meticulously install the lifts around the supports an flood settle and pack which requires a lot of time and a lot of water. You also need to be very careful to be filling pool at the same time for proper support of walls. 3/4 clean stone is a bulletproof and cost saving in the end. So the moral of this story is you probably have the best material to try and deal with settling a incorrectly backfilled area to support your patio. The key is flooding the area as many times as possible. The absolute best approach now (short of digging it all out and properly compacting back into place) would be to make a dam around the entire area where the deck will be.
You will want to use at least 6" of processed gravel plus 1 " of leveling sand plus 2-3" of pavers so your sand grade now should be at least 9" below proposed finish grade. Build a dam that will retain about 6" of water and do your best rain dance.. :) . Be absolutely sure it is well below the top edge of pool so you do not get water in pool. I would get some pallets and plywood then cover with false turf to get access to the pool for the season an leave the dam in for the winter. If you can get some 4" black coil pipe and pipe a few gutter downspouts too the area it would help a great deal as well.
 

jimmythegreek

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Aug 10, 2017
2,626
Morris Cnty NJ
Key to sand is properly done. Pushing sandy dirt into the overdig is not the way to do it. Flooding is a great help and used by alot of fiberglass installers. Cant do proper mechanical compaction against a liner pool without messing it up. Whatever you do insist on geotextile fabric over the sub base under your paver base it's cheap insurance
 
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ajw22

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Jul 21, 2013
18,959
Northern NJ
I think with sand you need a retaining wall. I don't think you can slope it with some dirt, plant grass on it, and not have it lost to erosion over time. You can give it a try and if the slope doesn't hold then build the wall.
 
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Rich D

Bronze Supporter
Aug 3, 2018
783
MA
It really depends on what you were planning on doing with the space beyond the patio. Sloping dirt is always cheaper than building any type of retaining wall. Do you have enough fill on site to do it with your existing sand? Your sand can be stabilized so the water will run over it depending on how steep it is of course. You can usually figure on being able to stabilize a three to one slope with either stone grass or plantings. If you start getting closer to a 2 to 1 slope you will need something more like a trap rock. 3 to 6 inch rock with filter fabric underneath it. You can set up some steaks and strings and and figure out exactly how much pitch you were going to have on your slope.
A few more pics of the surrounding area would help a lot.