Externally mounted covers are rolled up above the water level, preventing the slatted cover from coming into contact with the water. For this reason, the reel system must be enclosed on three sides. If no protective cover has been ordered, you must build an enclosure before installation of the slatted cover. The enclosure must not allow any sunlight or heat through, and it must not be in direct contact with the slatted cover because this will result in the transfer of heat from the enclosure to the slatted cover. This would result in the accumulation of heat and deformation of the slats.