Knowledge Pool

Repair Of Pool Floated By Hydrostatic Pressure

To reinstate a floated pool to proper condition three procedures must occur. The first is to fill any remaining voids under the pool in order to reestablish uniform support of the pool from the

 underlying subgrade. After accomplishing the first task, the second is to relevel the bond beam of the pool. And the third task is to repair any cracks in the structural shell of the pool.

There are several methods available to fill the voids under the pool. The choice will be up the involved parties based on the economics of each option. In similar situations, we have seen contractors remove and replace portions of, or the entire pool floor, in order to fill and compact the voids under the pool.

We are aware of another method that I’ll call mud jacking that has been used by one of our clients on the East Coast to successfully reestablish support of over a hundred floated swimming pools without experiencing a subsequent failure on a pool repaired in this manner.

I actually traveled to the East Coast to observe and participate with our client in the mud jacking, i.e. lifting and re-leveling, of a pool that had floated due to being emptied when high groundwater was present. Because of the low-tech methodology, this technique may be the simplest and least expensive way to repair a floated swimming pool and can be performed utilizing only a standard concrete pump and as few as four unskilled laborers.

Picture 5

The technique is to simply float the pool in a flowable conventional grout mix pumped under the pool (using a standard concrete pump, hose and nozzle) through a grid of 2 inch diameter holes cored in the pool floor (see the attached picture 5). The grout mix utilized is similar to the mix used to grout a wall except that a set retarder is added to maintain the flowability of the grout for 4 to 5 hours. The pool I participated in had to be lifted to be releveled and the non floated section was raised 9 inches to re-level the pool and to fill in any voids under the pool.

After the voids under the pool have been filled and proper or support of the pool reestablished, the existing tile and coping will be removed from any out of level portion of the pool. The bond beam of the pool will then be raised or lowered as necessary to reestablish a level “top of bond beam” surface.

Any cracks in the pool can be repaired utilizing epoxy injection. The crack repair can be accomplished either before or after the process of releveling the top of the bond beam.