(yet another) Backfill Question

GaryParr

Member
Aug 21, 2020
19
Rhode Island
So, backfill on my pool should start soon. We are planning on waiting until next summer before pouring a concrete patio, so I think we would be OK with just backfilling with the excavated dirt. I think. Assuming a harsh New England winter followed by the typical never-ending spring rains and by summer I should be good for concrete. I think.

However, due to the amount of rather large rocks that came out when they dug the pool, I will need to supplement with additional material. Does it make any kind of sense to do a mixed backfill? Perhaps 50% gravel, 50% dirt? If I do that... would it be gravel first, dirt over? Or try and gravel as close to the pool as possible with dirt outside of that? Or is this just really dumb and I should stop trying to save money by using this big dirt pile in my yard and just do the whole thing with gravel?
 

duraleigh

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Apr 1, 2007
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Sebring, Florida
I should stop trying to save money by using this big dirt pile in my yard and just do the whole thing with gravel?
Now you're talkin'!

You will never miss nor remember the few hundred bucks you spend on good clean fill rock, but you will be reminded daily by the cracks in your decking if the settling was not complete.
 

Rich D

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Aug 3, 2018
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Even after a nasty New England winter your soil will not settle enough to properly support a concrete deck. Over time it will settle more and your deck will sink and crack. This would be a terrible choice of where to try to save some money. Anything worth building is worth building on a solid foundation. You should backfill with all "Clean Stone". Be careful on the terminologies used on this forum. In New England we like to call a mix of sand and dirt "Gravel". It seems the rest fo the country calls clean stone "Gravel".
 

Rich D

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Aug 3, 2018
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MA
At the bare minimum you should also be putting in a collar drain piped to daylight or a sump, to be sure your liner does not float and to aid in the replacement of a liner in the future. This is very, very cheap insurance to install at this point. To install one in the future if you have issues is very costly and will never work as well because of the limited access you will then have with the deck and landscaping in the way.
 

cowboycasey

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I agree with Dave, spend a couple extra bucks to save your deck from cracking, A sump pump pit would be a great addition now... :)

57 stone is about a half inch in size and is used to backfill the side walls of a pool. 57 stone works well locking together for good compaction when it is dropped into the overdig area around the pool. Its 95% compacted out of the bucket. A light hand tamp or plate compactor and you are good.