Why are Solar films Unsuitable for installation onto Polycarbonate roofs?
Solar film products have a contraction and expansion rate equal to that of glass, since this is the material that they were designed to be bonded to. Polycarbonate on the other hand has a much higher expansion and contraction rate. If a Solar film is mounted onto Polycarbonate the film is stretched when the sun is on the glazing because the roof glazing expands, at night, or when the roof cools it contracts. Because the expansion/contraction coefficients are not compatible the film bunches when the roof contracts which leads to an unsightly appearance and enables water to percolate behind the film leading to deterioration of the adhesive, and the film. The life expectancy in the UK climate is reduced to three to five years which is unacceptably low, apart from the unsightly appearance.
