Many large flat roofs of distribution centres, cold stores and logistics halls in particular are not designed for the installation of solar panels. In order to still be able to install solar panels, additional measures are required, such as strengthening the building structure (roof reinforcement), mechanical attachment of the solar panels to the substructure or special lightweight panels. 

Carrying and residual capacity 

According to the building code, the load-bearing capacity of roofs should be approximately 60 to 65 kg per m2. For various reasons, the residual capacity (the possible additional weight to be added for the placement of solar panels) has often already been used. For example, because an extra insulation layer has been added and the roof covering has been overlaid. Or because savings were made on the steel construction during construction.  

Regular solar panel installations for flat roofs weigh approximately 15 to 20 kg per m2, including mounting frame and ballast, depending on the location, terrain category, wind zone, building height, mutual distance and angle of inclination of the panels. 

Minor roof adjustments include: 

• Reducing roof loads (such as adjustments to drainage, gutters, downpipes and emergency overflows).
• Use of special mounting systems (from truss to truss), which means that the system only rests on the trusses and intermediate roof parts are not loaded.  
• versterken van de dakconstructie, zoals het aanbrengen van extra
  balken, spanten, trekstangen, kolommen of schotten.   
• application of lightweight solar panels.