Polycarbonate Sheet

One of the simplest methods of getting natural light through a steel roof is the inclusion of translucent sheets which match the steel profiles. It is preferable to use profiled translucent cladding in single widths so that they can overlap, and be supported by the steel cladding on both sides. It is also preferable to position the lengths of translucent cladding at the top of a roof run so the high end can lap under the capping or flashing and the low end can overlap a steel sheet. This is because the translucent cladding will readily overlap a steel sheet but the reverse is difficult.

Building regulations require a safety mesh to be fitted under translucent cladding. Because of its greater thermal expansion, translucent cladding should be fixed using oversized holes and sealing washers recommended by the translucent cladding manufacturer. When used with concealed fixed claddings, ensure the fasteners do not penetrate the steel cladding. There are translucent products available that easily accommodate this and some translucent products have a clip-fixing system to allow thermal movement. Don’t exceed the maximum support spacing specified by the translucent cladding manufacturer.

Skylights increases the transmission of solar heat. Generally speaking, heat transmission is proportional to light transmission, so the more sunlight that enters a building the hotter it will be. Clear, uncolored fiberglass has good light transmission of about 65% but this means on a typical summer day, with peak solar radiation of 850 W/m2, transmission through a clear fiberglass skylight would be about 550 W/m2.