They are the preferred option if you want a level deck pool or an infinity pool, and can also easily incorporate a tiled spa as part of the structure. They also lend themselves more readily to the installation of safety covers. The fastest and most popular method is to use Gunite or Shotcrete, poured in situ. Pool shells constructed using these methods are all built to BS 8007, and once formed, the shell is water tight, and does not rely on waterproof renders or applied finishes. We generally render them anyway, to provide a suitable surface for tiling. This method of construction is not normally recommended for the DIY enthusiast.