There is a lot of confusion out there about what border to leave when installing solar panels. Both the NIC/EIC and City and Guilds teach that when installing solar PV on pitched roofs we should leave a 300mm boarder from every edge. This is due to wind up lift and if we look at the BRE digest 489 it confirms that for solar PV closer to any edge than 300mm requires structural calcs by a structural engineer.
In Cornwall we have strong winds, very strong winds, this would suggest that we should implement the 300mm boarder, so then why are there still so many solar arrays up in Cornwall and continuing to be mounted right on the edge of pitched roofs. By offering this advice to customers we are still losing work to those companies that don’t follow the rule, maybe they are not from Cornwall or they have not done their research but we get gales! and lots of them.
The issues I have come across are companies and clients who see this edge protection as a loss in terms of return, and there are no recorded incidents of PV blowing off pitched roofs, but there are roofs collapsing and insurance companies not paying out because structural surveys were not completed on properties before the mounting of PV. This is being put down to over loading and lack of survey knowledge and studies yet to prove that it is lack of edge protection. So is it scare mongery? Who benefits from that? Either way the new regs arrive in May for MCS version 3 and it calls for 400-500mm border and we will be sticking to them, we have missed out on work because we have stuck rigidly to the edge protection advice, with or without the extra work we have never had a roof collapse, we’ve never even had a loose slate or tile and we believe that this is because of solid surveys and anything out of the ordinary we bring in an independent structural surveyor so you are constantly protected and we can all sleep soundly during the next 20 years of your investment.