One of the worst issues that can come up in gunite pool construction is rebound. When shooting a gunite pool this is the material that sprays off the application surface during the gunite process. Rebound is usually made up of more dense particles (which often ricochet). This material seldom contains adequate cement, water or the proper density in order to develop appropriate strength. This material, therefore, should never be used in any circumstances where strength and durability are needed.
For many years pool contractors and pool builders alike have known the adverse effects of using rebound. In an inground pool gunite isn’t trowled like on a smooth concrete sidewalk. In pool construction the dry gunite material is often mixed at the truck with water added at the nozzle. It’s then sprayed at a high velocity through a hose attached to a compressor by an operator. The gunite process involves spraying this material and forcing it to condense into a highly durable shell with a minimum PSI strength of 2,500 pounds by square inch. Rebound is the material that ricochets off during the application and sculpting of the inground pool and should never be used.
Good pool contractors will discard this material rather than using it in your pool. They know that rebound is less durable and won’t cure properly. However, in some cases pool contractors will try to cut costs and use the rebound to create steps, benches or fill in spots that are rough. This is not advisable and leads to delamination and cracks.
A good pool contractor will not use the rebound material. It is less dense, less strong and no longer being shot under high pressure and will not cure nearly as hard as the gunite that was properly placed. The rebound should be discarded. However, to save costs, some gunite crews would use the rebound to create steps, benches or to fill in corners. This will lead to weak spots in the pool finish that can delaminate or crack once the pool finish is applied. Today, many pool builders opt to use Shotcrete for this very reason. Shotcrete is already pre-mixed and has a high PSI needed in pool shells.
Pool Contractors and Pool Builders will often fire a gunite crew caught using rebound material to build a structure. It’s one of the worst things a Pool Builder can do and a shady cost cutting way to stick it to the homeowner to save a few bucks. It should never be done under any circumstances ever.
PoolContractor.com is affiliated with over 25,000 pool builders and pool service companies around the country. Get a free quote on building a new pool, remodeling an existing one, or servicing your pool now.