Typically, interior swimming pool construction in mid-rise and high-rise begins with a concrete vault or “box” that is built at the time the building is constructed. The bottom and sometimes the sides of the vault need to be shaped and filled with lightweight void fill before the concrete or shotcrete is installed, creating the finished pool. That lightweight void fill material is usually .9 lb or 1.35 lb expanded polystyrene.
There are two different ways that the EPS can be supplied and installed. The EPS panels can be provided pre-cut and pre-tapered to fit the inside of the pool shell. The pieces are labeled so the installer know what goes where. This way very little trimming is required and the foam should install fairly quickly. The downside to this method is that there are a lot of unique pieces of EPS to organize and sort through during the installation process.
The alternate to this method is for the pool contractor to limit the number of unique pieces to one or two different sizes. This makes finding pieces very easy but will require more cutting in the field. Since the pieces are typically 2 to 3 inches thick, they will cut easily with a hot knife, circular saw or reciprocating saw.
This experienced swimming pool construction company in Pennsylvania constructs a lot of swimming pools for health clubs, YMCAs and private organizations throughout the northeast. They have learned over the years that it is easier for them to work with all the same size material instead of having the EPS precut and pre-tapered for the different areas of the pools. For this project in New York City they used over 700 sheets of 1.35 lb density EPS 2 inch x 4 feet x 8 feet. Another advantage of using the same size is any left-over material from a project can be used on the next project.