Preparation of the perfect subgrade leaves support below ground that is invisible when the pool is complete. Nevertheless, improper preparation of the subgrade makes itself very visible when the pool is finished in the form of cracks, shifting and settling of the concrete around swimming pools. Nobody likes to have to go back to a finished job and make repairs because of problems with poor preparation of the subgrade. Every qualified concrete contractor and those who work with decorative concrete or stamped concrete know the importance of the subgrade.

Preparation of the Subgrade or Providing Alternative Support

For a pool surface to be level, the subgrade must be prepared or another method used to provide sufficient support. All backyards need fill to prepare a level area for the swimming pool deck. The difficulty is that the fill varies in depth significantly. It is not always apparent whether the fill material is packed and settled.

Three optional ways to support the pool deck include:

1. Allow enough time for all the subgrade fill to settle.
2. Use premium fill or stone to level the subgrade.
3. Provide support for the pool deck utilizing concrete piers.

Option 1 takes time that is usually not available. Option 2 is usually too costly, especially for larger areas. For most swimming pool decks, the most efficient way to provide support is option 3, using strategic placement of concrete piers around the perimeter of the pool.

Alternative Support With Concrete Piers

Steel-walled pools have deck supports that are bolted to the wall and which are sufficient to support about four feet of pool deck. To extend the deck further for steel-walled pools and for all concrete pools, concrete piers are the solution.

Concrete piers placed at strategic locations to support the deck are installed in a six-foot-by-six-foot grid. This means placing a pier every six feet away from the pool edge for concrete pools (or from the four-foot limit of deck support that is part of the steel-walled pool construction). Then, in the other direction, the piers are also spaced six feet apart. This six-foot-by-six-foot grid extends as far out from the pool’s edge as desired to support decks of any size by simply continuing to repeat the grid pattern.

With support from concrete piers below the deck, any shifting of subgrade or settling will not have any impact on the structural integrity of the pool deck above it. For detailed information and tips on how to install concrete support piers, please see How to Build the Perfect Pool Deck - The Subgrade, written by Deco-Crete's owner, Jason Geiser.