Backfilling With Dirt – Pros and Cons


It is not all that uncommon for a builder to use dirt to backfill a pool.  Traditionally this is not the best material to use for backfilling a pool.  The reason being is that the dirt will settle over time.  Typically when the pool is dug, it will be dug about three feet wider than the actual width of the finished pool.  The over dig is what allows the builders to run the plumbing and electrical around the pool to the proper locations.  This over dig will be the same depth as the shallow end of the pool.  When the pool is backfilled with dirt, that over dig area around the pool is very susceptible to settling.  In fact it is almost definitely going to settle.  So what happens to the concrete deck or pavers around the pool when that dirt settles?  Well the worst case scenario would be that it too will settle, leaving you, the homeowner with a huge mess.  The other outcome, depending on if the builders used deck supports, will be large voids underneath the concrete that will have to be filled in.  That means that it will be up to you, the homeowner to either fill it in yourself at a small cost, or pay someone to come in and do it at a higher cost.  Either way you will have some extra work to do or have done after your pool is complete.  So what is the best material to backfill with.

I have found that when a pool is backfilled with a non-compressible stone, like pea gravel or stone chips then the over dig area is far less likely to settle, and if it does it will probably be so minuscule that you won’t be able to see it.  Now you may be asking yourself, “why would a builder backfill with dirt over stone?”  It really just comes down to cost.  Obviously using the dirt that came out of the ground when they dug the pool won’t cost them anything, whereas bringing in a couple dump truck loads of stone will cost much more.  In my opinion this is something that should be made clear in the planning part of the build process.  Many builders will use this as a selling point.  For instance lets say you have been talking to a couple different builders, and the first one gives you a quote for the cost of your pool and installation. This will allow the second builder to quote you a better price by using dirt to backfill.  It may not be a whole lot but a pool builder is in the business of getting business.  If by telling you that they can build the same pool for a few hundred dollars cheaper and you accept it then they have done what they set out to do.  They can choose to let you know how they can do it cheaper or not, that part is up to them.

Deck Supports Around Pool

On the other hand some builders may argue that backfilling the pool with dirt is a perfectly acceptable way of backfilling as long as they take the proper precautions.  By proper precautions I am referring to support.  Most in ground vinyl liner pool manufacturers make deck supports and other bracing that is designed to assist in supporting the weight of the concrete decking around the pool.  Some builders rely solely on those supports to hold up the concrete.  Another possibility is that the builder has the mindset that they are doing exactly what needs to be done to build the pool.  They understand that the deck supports are designed to support the weight of the concrete and if they use them on the pool then there is no need to backfill with stone.  At that point they have successfully done their job and if the dirt under the deck settles after the completion of the pool then it is not their responsibility to add more dirt.

The reason I bring this up is just to make you aware of it.  If you are thinking about having an in ground vinyl liner pool built then I want you to know what to expect.  That way you can ask questions before hand and possibly prevent a unexpected surprise after the pool is complete.  You can always insist that the builder backfill with stone.  It may cost you a bit more money but that is money that you would be spending anyway after the dirt settles to fix the grade around the pool.  Most builders will be happy to accommodate your request.  After all if it gets them your business, and adds a little more cost to the project then I don’t see why they wouldn’t.  However if a builder tries to tell you that the dirt will not settle then you may want to look into having another company build your pool.  They may say that they are going to compact the dirt so that it will not settle, but in reality there is no guarantee that compacting will absolutely, 100% prevent the dirt from settling.

This is just something that I want my readers to be aware of.  If you are having a pool built it is important to understand what is going on.  That way you will know if something “fishy” going on.  I have heard of builders not coming through on what they said they would do.  In fact I personally know a guy that gave his builder a large sum of money up front only to have the builder dig part of a hole in his backyard and then take off to florida.  Unfortunately this type of thing happens all too often.  That is why you want to make sure that you are dealing with a reputable pool builder.  For more information on how to make sure you get the right builder check out my other posts with “builder” in the title.