The pool cover has shrunk

The manufacturing of solar pool cover material uses plastic extrusion under heat and pressure in specialised equipment. It is the nature of the process that some subsequent settlement of the material is to be expected. Up to 1% shrinkage can normally occur in the length of a pool cover during the first 2 weeks, with the maximum of the settling occurring in the first few days (a 9.0 metre cover can shrink up to 90 mm). To allow for this, an extra (minimum) 300 mm is added to the length of the cover from the measured size of the pool to enable the installer to cut the cover to shape and allow an upturn of 50mm – 100mm (average 75mm) all around the pool. This is much more than adequate to compensate for the expected 1% maximum shrinkage in length. If a pool cover has shrunk more than 1% in length, or it has shrunk in width (shrinkage in width does not occur naturally), then the only possible explanation is that the cover has experienced very significant overheating when stored off the pool.