Best mounting system for flat roof

yp70479

I have a 2.4 x 6.0 m south facing flat roof that is just going to waste. Can any one suggest a suitable solar PV mounting system that would enable me to install more panels (4 portrait mounted  i think)? Does anyone have experience of such systems? Prevailing wind is usually SW and can be quite strong at times as it blows across open ground. How strong does the underlying roof have to be? Any idea of roof joist dimensions? I will be getting the existing roof renewed, but don't really want to have to screw into it because of the potential for leakage.

Screwdriva

yp70479 said:

Does anyone have experience of such systems? 

The projects I help out with almost exclusively use Van der Valk flat roof mounting systems (see image below). The specific weight added to the mounts are specified (with inputs from VDV) as part of the design prior to installation, with the sides and backs blocked off to resist strong winds, except for bifacial panels (see lower part of image), where more weight is used). The total weight that must be supported hovers around 100kgs, which is typically not an issue for most roofs. 

yp70479

thanks. with roof mounted panels you need 30-40cm clearance near gutters, ridges or hips - do you know if there are similar clearance requirements for the Van der Valk system. I've heard 50cm touted about but not sure if this was specific to the system used

Screwdriva

Frankly, this varies by installer and project but 500mm is the correct default clearance for VDV. 

yp70479

Have you come across anyone mounting panels portrait rather than landscape - I have seen VDV do a rig for tis, but don't know how common it is, or if there are any other constraints?