Translucent sheet roofing – loss of transparency


UV (sunshine) 


  • check first whether cleaning makes a difference

  • replacement roofing, often a type of polycarbonate, is widely available in flat and profiled sheeting

  • products that have UV treatment on one side generally have a “This side up” sticker. Remove stickers immediately after installation

  • follow the sheeting manufacturer’s recommendations around purlin spacing and roof pitch

  • some products come with their own fixings. Fixings should be installed in the centres of oversized holes. Tighten without overtightening to allow slight expansion/contraction of the sheeting

  • before using silicone sealants or other products in contact with the sheeting, check that they are compatible

  • do not walk directly on the sheets. If it is necessary to walk on the roof, put walk boards in place

  • a slight reduction in light transmission over time is not uncommon


Insufficient rain washing resulting in deterioration of UV-resistant coating 


  • all types of cladding that do not receive rain washing should be washed on a regular basis with a clean cloth or sponge and soapy water. In a clean rural environment, once or twice a year may be sufficient, but in a coastal or geothermal environment, or where there may be industrial or agricultural chemicals in the air, washing once every 3 months may be necessary

  • if the roofing needs replacing, see details above