You’re building your own inground swimming pool and now it’s time to start backfilling around the walls and braces. Your inground pool kit should be completely assembled and your concrete collar or footing is already poured around the outside of your pool - generally 8” to 10” up all around the frame work of the pool. You may have already installed the pool liner and have filled the pool with water, although this can be done after you backfill around the pool walls.
Step 1: Swimming Pool Backfill Material
When you dug out your hole for your swimming pool we had you separate the material you dug out; a pile with your grass, a pile of the top soil and the remaining material that may be useable for backfill material. If that material is a gravely mix that seems compactable - you can use that. If this third pile has many large rocks, or is a clay based material or red pan, or any material that retains water, you should avoid using this as backfill against your inground pool walls.
It's expensive to truck out bad fill, and truck in gravel, but good backfill material is important against the pool walls and as support for your pool deck. If you do need to bring in more suitable backfill material you want a good gravely mix or just plain gravel or any compactable material. Your local sand and gravel yard can advise you of the best choice in your area.
Step 2: Arrange for the Heavy Equipment
With the proper backfill material onsite, we are ready to begin the process of backfilling our inground pool. You could use a shovels and several workers, but it's probably easier, faster and cheaper to bring in a Skid Steer loader, Bucket loader or a Track Hoe for this part of your DIY inground pool project.
Step 3: Backfill - Tamp - Backfill - Tamp
In this phase of our DIY pool project, we will place our fill material into the trench around the pool, in phases - all the way up to the top of the wall. First, push in about 1 ft of your material all around the pool. Then compact this initial layer, using either a gas-powered compactor or a heavy hand tamper. You'll find both to be a lot of work, but the gas-powered tamper (shown right) will complete the job more quickly.
Go all the way around the pool - all the material we just put in must be compacted fully. After the first layer is done, push in your next layer of material and compact it in the same manner as the first. Continue in this manner, one foot at a time, until you come within a foot of the top of your pool wall.
Step 4: Final Layer of Gravel
For the last layer we want to use the best backfill material. I always suggest using a 8-12 inches of bluestone gravel for the top layer. This will give a good foundation to support your concrete pool deck. Put the top layer of gravel in a little higher than your wall and compact it extremely well. This is what our patio will sit on top of so we want to take extra time on this layer to prevent cracking or settling of our pool decking.
Step 5: Soak Down the Backfill
We have all our material in place and compacted our next step will be to soak the whole area thoroughly, for hours. Placing sprinklers around the pool and letting them run for 2 or 3 hours usually does the trick. After a super-soaking, let the ground surrounding your pool dry up; this usually takes a day or two. You will notice that even though you spent all that time compacting your layers, the area around the pool will have settled a few inches. This is good and exactly what we were hoping for. If desired, after a few days, you can repeat the process, to ensure that the layers are as compact as they can be.
Step 6: One More Backfill Layer
One more layer of gravel or stone dust can be placed on top - again to bring it up to the the level of the pool. Use more material up against the pool walls, because as you tamp this final layer, you will grade it, to slope it away from the pool. The slope should be about 1/4" for every foot of pool deck. If you are installing a 4 foot wide pool deck, the outer edge should be 1 inch lower than the edge against the pool. No need to be exact, any difference will be made up for as the concrete deck is poured.
And that's it! Backfilling your inground pool is one of the happier phases in building your own inground pool. You can now really see it coming together, and the excitement will fill the house. Very few steps in your DIY inground pool project remain. When you backfill your pool using our methods described above, you can quickly schedule the concrete truck to make another visit and have your pool deck poured, without having to wait for the surrounding ground to settle.
SPP Pool Expert