Permanently Fix a Settling Pool Part I | Ask a Registered Engineer
“Two years ago we mud jacked our cracked and settled pool. Today our swimming pool is worse than before we repaired it. How do you permanently fix this problem?”
This is a common complaint amongst pool owners. After I walk you through what is happening in the ground, you will understand that mudjacking isn’t a permanent solution, whatsoever. Throughout the next series of posts, I will walk you through how you should permanently fix a settling pool.
Understanding Pool Construction
The first task to build an in-ground pool is to excavate a hole in the soil where the pool will be located. Following the excavation, the process of constructing a pool consists of forming a steel-reinforced concrete shell to contain the water.
Learn How Your Pool Effects Your Soil
Let’s think about what effect the new pool had on the underlying soil that is supposed to support the pool. Not only do you have the weight of the thick steel-reinforced concrete shell to think about, but you also have the thousands of gallons of water added to that. The soil beneath the pool is required to support this concentrated weight. The settling you are experiencing is a result of the underlying soil having insufficient strength to support the weight imposed by the pool. The pool is causing the underlying soil to consolidate, which is causing the pool to sink.
If soil consolidation isn’t enough of a problem, most pools are constructed with a shallow end and a deep area. This is a problem because there is an imbalance of weight on the soil. Less weight is placed on the soil on the shallow end, and more weight on the deeper area. This weight imbalance on the soil below the pool causes the deep area to settle more than the shallow end. In many cases, a fracture will occur on the slope between the two areas. Now you have a pool that’s lower on one end than the other, and cracked in the middle!
Here is a quick explanation that should help you understand why you should never repair a settled pool with mudjacking. Mudjacking is a process of injecting wet concrete between the bottom of the pool and the underlying soil. The deep area of the swimming pool usually settles the most. When the contractor leveled your pool for repairs, they likely added more concrete “mud” under the deep area. Thus adding more weight to the already weak, consolidating soil below the deep end of the pool.
Want more information on how to permanently fix a settling pool? Check out our next post in this series here. Have more questions on settlement? Check out our blog for more information and additional resources.