For those of you who wonder if pouring the decking immediately is a good idea, I offer this photo of my build. The backfill was done two weeks ago. The original level of the dirt was just above the coping. The dirt settled this much after only one rain event. Now I know why my PB wants to wait 6 weeks to pour the deck and encourages the use of sprinklers in the meantime. They are coming back out today to do another layer of backfill. Otherwise all plumbing and electric are finished.
F500 build - backfill settlement
- Thread starter F500
- Start date
Most pool builders I know use granular fill to back fill with so this isn't an issue.
Riles_J
0
I'm not sure what is typical of pool builders, but on construction sites fills are placed in lifts (usually 6 inches or so) and compacted or walked in to prevent this type of settlement. If they just push all the dirt back in the hole all at once then settlement will certainly occur. My fear would be that the contractor comes back and pours the deck after 6 months and then the soil continues to settle.
Soil in Louisiana is a mix of sand and big chunks of clay. This back fill was walked in to compact it. It is impossible to fill all of the voids created by clay by compacting so water is needed to wash dirt around the voids. Crushed rock isn't used because we have none in the area so it is very expensive to get.
We talked to several PBs when doing our research and this settlement is common in this area.
We talked to several PBs when doing our research and this settlement is common in this area.
My pool has a large (2500') deck area and the backfill was critical before pouring concrete.
I learned that each area of the country is different. Each soil compacts differently so no one rule applies. My soil was very similar to F500's. Similarly, the cost of rock for the area I needed was absolutely prohibitive. (although I did fill the dig around the pool with rock).
I backfilled in layers and ran a "jumping jack" compactor inbetween layers. In addition, my 14,000 lb backhoe was used to bring in the layers so the soil was further compacted by it.
Six months later, when I poured the concrete, (Note that nowhere in here did I mention I was fast!! :lol: ) the soil had still settled about 1-2 inches from the level that I had thought would be the final grade. It's amazing to me how difficult it is to get some soils compacted.....mine certainly was.
I learned that each area of the country is different. Each soil compacts differently so no one rule applies. My soil was very similar to F500's. Similarly, the cost of rock for the area I needed was absolutely prohibitive. (although I did fill the dig around the pool with rock).
I backfilled in layers and ran a "jumping jack" compactor inbetween layers. In addition, my 14,000 lb backhoe was used to bring in the layers so the soil was further compacted by it.
Six months later, when I poured the concrete, (Note that nowhere in here did I mention I was fast!! :lol: ) the soil had still settled about 1-2 inches from the level that I had thought would be the final grade. It's amazing to me how difficult it is to get some soils compacted.....mine certainly was.
It does vary geographically. Here in the midwest they constructed a slope off the backside of our pool. We built our pool into a hillside.
Our options were to either build a retaining wall on the downslope side of the pool or create a slope without a wall. We thought the slope would look more natural and save some $$.
Well it sure looks cool but it actually cost as much as the wall would have.
The concern is that if built improperly it could erode or settle. It also provides structural support to the back wall of the pool. They excavated out an enormous level area on the downslope side of the pool and then build it back with 8" lifts of soil that was then compacted layer by layer. A geotechnical engineer used some device to actually measure the soil compaction at each layer.
Was tedious but fascinating.
Our options were to either build a retaining wall on the downslope side of the pool or create a slope without a wall. We thought the slope would look more natural and save some $$.
Well it sure looks cool but it actually cost as much as the wall would have.
The concern is that if built improperly it could erode or settle. It also provides structural support to the back wall of the pool. They excavated out an enormous level area on the downslope side of the pool and then build it back with 8" lifts of soil that was then compacted layer by layer. A geotechnical engineer used some device to actually measure the soil compaction at each layer.
Was tedious but fascinating.