Infinity Pools(also named negative edge, zero edge, vanishing edge or disappearing edge) is a swimming or reflecting pool which produces a visual effect of water extending to the hor izon, vanishing, or extending to "infinity". The term also is used to describe perimeter overflow pools (pools that may be on level parcels, wherein the water flows over one of more edges).
One type of location in which the effect is particularly impressive is where the vanishing edge appears to merge with a larger body of water such as the ocean, with the sky or(if the pool is located on the side of a hill or field of green), with foliage.
Vanishing edge pools are often very expensive and require extensive structural, mechanical (hydraulic engineering) and architectural detailing. Since they are almost always built in precarious locations (cliffs, mountain tops, beach front,etc.), sound structural engineering is paramount. The structural engineering must be based upon the geological conditions found on the site. A geotechnical report is commissioned prior to the commencement of the structural engineering. The high costs of these pools is often found in the foundation systems that anchor them to the hillsides.
In reality the edge of the pool terminates at a weir that is 1/16 - 1/4" lower than the required pool water level. A trough or catch basin is constructed below the weir. The water spills into the catch basin, from where it is then pumped back into the pool.
The construction technique has not yet been developed for a vinyl liner pool to include a vanishing edge, so the swimming pool must be constructed of concrete using concrete blown onto a steel frame. The technique is most commonly referred to as gunite.
