Summer is here, and as many homeowners know, the 100-degree days make us all thankful that we have a pool to soak in to cool off. Many homeowners experience shifting in their pool decks that disrupt their blissful 'cool off' sessions and cause unsightly trip hazards that can damage their largest home upgrade.   Our customers commonly ask why their concrete around the pool shifts. There are several reasons this can occur, but we find that there are 3 most common reasons this happens.  


1: Un-compacted Backfill of Soil

When a pool is installed, the dug hole is typically made 3-5 ft larger than the pool itself. This is done to provide access for the plumbing and structural elements of the pool. Once this is complete, the installers will backfill using the leftover soil and lightly tamp the dirt for compaction so as not to disrupt the soil. When the pool is installed, there is no water to counteract the soil's weight, so the installers try their best not to over-compact the dirt so they do not damage the pool walls, plumbing, etc. Over time, this soil naturally will compact more with the changing seasons. Then, the concrete on top of that soil will shift and move, leaving uneven concrete.


2: Washing out underneath the concrete

Most commonly, the soil under the was placed over backfilled soil. That soil is much more prone to absorbing or allowing pass-through rain water. This is because it is less dense than the undisturbed soil neighboring it. Water intrusion slowly washes out voids under the concrete coping and decks that slowly allow the concrete to settle. This can also be seen when leaks in the plumbing lines connect to your pool's pump. Irrigation lines, undirected downspouts, and patio runoff all contribute to the issue of soil washing out under your pool's concrete surfaces. 


3: Extreme Drought

When we experience seasons of little to no rain, the clay soils around our pools begin to lose their density. Naturally, the soil starts to shrink in size because of the lack of moisture. When the soil shrinks, it creates voids under the concrete that cause the concrete to shift over time. Because the soil immediately around the pool is backfilled soil, it is common to see more shrinkage in that soil than the dense virgin soil that may be found in your yard that has never been disturbed by heavy equipment. Subsequently, the large cracks left in the soil from shrinkage leave paths for water when the rains return, and then washout increases the likeliness of settling concrete. 

With these most common causes, there are ways to prevent them from occurring. Maintaining proper drainage away from the area and addressing control joints or cracks with approved caulking is best. If movement occurs, structural foam injection can easily lift the pool back to its original position. If you want to learn more about how these repairs are done, feel free to contact us at or give us a call at 479-279-6700