Permanently Fix a Settling Pool Part II | Ask a Registered Engineer
POOL SETTLEMENT REQUIRES A PERMANENT REPAIR SOLUTION
The first thing to understand is that the continuing settlement of the pool suggests that the soil below the pool has insufficient strength to support the weight of the filled swimming pool. A permanent solution for settlement is to install structural underpinning with sufficient capacity to reduce, or eliminate the pool weight that is bearing upon the consolidating soil.
Helical Screw Piles are a permanent solution to pool settling problems. A helical screw pile works much like a wood screw. A wood screw has threads that advance it into wood to secure objects. Helical Screw Piles act in a similar way when screwed into the soil. They are constructed with one or more steel plates connected at the bottom end of a long pile shaft. The helices allow the pile to advance into the soil as the pile shaft is rotated.
When the pile is embedded into competent load bearing soil below the consolidating soil under the pool, the pool weight can be transferred to the pile, which then distributes the pool weight into the dense soil deep below the surface. The process of supplemental support and restoration of the pool isn’t any more difficult than the process needed for a mud jack repair, but helical pile underpinning is going to be more costly. A structural repair such as this offers great value for long-term results because once the pool is properly supported, there can be no more pool instability or settlement.
A REGISTERED PROFESSIONAL ENGINEER CAN INSURE LONG-TERM RESULTS FOR A SETTLING POOL
In order to insure a long-term repair, you really need an engineer to properly design and prepare product and installation specifications. Many foundation companies might offer free inspections and estimates, but it is worthwhile to pay for an engineer’s proposal. For instance, the mud jack contractor that made the previous repair probably assured you that a mud jack injection was a great repair for your situation, and perhaps you even received a one year guarantee. However, the “guarantee” is a gimmick because settlement is a slow process that occurs over time.
The reason you need a registered professional engineer at your side is because a proper pool repair requires professional expertise to insure long term support and stability. Licensed professional engineers are formally trained and they charge you only for time working on your project.
Unlike a foundation repair salesperson, the engineer makes no commission on selling you a product or repair work. The design process is complicated. The engineer needs to take measurements, make soil tests, calculate load and support requirements. The end result is you receive solid recommendations and specifications to solve the pool instability and settlement problem.
Keep in mind that every pool is different in size, shape and depth. The quality of the construction and the thickness of the concrete pool shell must be considered. The soil must be analyzed layer by layer to determine the soil capacity below the pool. Soil varies by location, and an analysis specific to your job site is required. Therefore, there is no “one size fits all” for pool repairs. An engineer, or foundation repair salesman for that matter, cannot immediately provide a repair design by just taking a quick look at a settling pool. Unfortunately, it’s not that simple. A successful pool repair requires engineering evaluation and design.
Check back next week for an in-depth explanation of the evaluation and design process! If you missed our previous post in this series, you can find that here.