There are many ways to build a vinyl liner in ground swimming pool. There are many things that go into building a vinyl liner in ground swimming pool. One thing that many builders do is install a sump pit just outside of the sidewalk that goes around the pool. Why do they do this?
It actually makes perfect sense when you really think about it. We all know that when it rains, the ground absorbs much of that water. The water that gets absorbed by the ground is what is know as groundwater. More often than not when a pool is dug the groundwater is visible in the deep end. If the hole were to be left like that, you would likely see that ground water begin to rise a bit, especially when it rains. Instead, pool builders finish building the pool and put a liner in. In some cases this process is a race against time. They have to get the liner in the pool and get water in before the groundwater rises enough to make the liner float. You may be wondering why the liner doesn’t float anyway, even after the pool is full. It rains all the time throughout the spring and summer right? Well the reason the liner does not typically float after the pool is full is simply because the weight of the water in the pool pushing down on the liner is greater than the pressure from the groundwater pushing up on the liner from underneath it.
Keep in mind that I said that a liner will not “typically” float after the pool is full of water. There are always some that don’t want to behave. This is why many pool builders install a sump pit right outside of the sidewalk around the pools that they build. It is more of a precaution. If the amount of pressure from the ground water pushing up on the liner exceeds the amount of pressure pushing down from the weight of the water in the pool, then the liner will float. Having a sump pit will allow you to remove some of the excess water from behind the liner to prevent the liner from having a chance to float.
If you have an in ground vinyl liner swimming pool that has a sump pit installed, then I would recommend using it, especially at times when there is a lot of rain. This will help to ensure you don’t have a problem with the liner floating.