The Superiority of Crushed Rock for Pool Deck Backfill
Choosing the ideal backfill material for inground pool bottom and deck construction is an important decision that impacts the durability, stability, and longevity of the entire structure. While sand and dirt are common choices, crushed rock emerges as the superior option due to its exceptional compaction rates, drainage properties, and long-term stability. In this blog, we dive into the research surrounding compaction rates and the behavior of various materials over time. Most pool companies use dirt or sand from the dig for backfill to cut the cost of hauling dirt and buying rock. At Super Pools we place the utmost importance on the quality and longevity of our builds which adds to the pool value as well.
Compaction Rates:
The general rule in pool construction is that the higher the compaction rate the better because the more compacted the backfill is, the better it is at load bearing and reduces the settling of soil over time.
We use a vibrating plate to ensure proper compaction. Improper compaction can cause pool leaks, cracks, movement on the pool bottom, and cracking of concrete decking. Research consistently demonstrates that when compacted using vibrating plates or rollers, crushed rock achieves superior compaction rates compared to sand or dirt.
Studies indicate that crushed rock can attain compaction rates ranging from 90-95% of its maximum dry density, resulting in a solid and stable foundation for the pool deck structure. In contrast, sand and dirt often exhibit lower compaction rates at around 60%-70%. [MQ Multiquip. "Soil Compaction Handbook" Multiquip Inc Rev A 2011. URL. Accessed February 9, 2024.]
Drainage and Stability:
Crushed rock offers unparalleled drainage capabilities, essential for mitigating water accumulation and preventing soil erosion beneath the pool deck.
The angular and coarse nature of crushed rock particles facilitates effective water drainage, minimizing the risk of hydrostatic pressure buildup and damage to the concrete structure.
Sand and dirt, while suitable for certain applications, may lack the drainage properties required to withstand the constant exposure to moisture and hydrostatic forces inherent in pool environments.
Long-Term Behavior:
The long-term behavior of backfill materials significantly influences the performance and durability of pool decks. Crushed rock, with its inherent stability and resistance to settling, maintains structural integrity over time. Research suggests that sand and dirt backfill may experience compaction, settling, and erosion, leading to surface irregularities, cracks, and potential structural compromise. [MQ Multiquip. "Soil Compaction Handbook" Multiquip Inc Rev A 2011. URL. Accessed February 9, 2024.]
By opting for crushed rock backfill, pool owners can minimize the need for costly repairs and maintenance, ensuring a safe and resilient pool deck environment for years to come.
Selecting the appropriate backfill material for pool decks is a critical aspect of construction that directly impacts structural integrity, stability, and longevity. Through meticulous research and analysis, it becomes evident that crushed rock, compacted with vibrating plates or rollers, surpasses sand and dirt in terms of compaction rates, drainage capabilities, and long-term performance.This is exactly why we choose to use crushed rock for our backfill and under concrete deck. We build pools that last by not compromising on the quality of our materials and processes. By choosing to build with us homeowners can enjoy peace of mind knowing that their pool deck will endure the test of time, providing a safe and enduring outdoor oasis for relaxation and enjoyment.
