Solar panel tray for flat roof

[mjc55]

Anyone on here used trays to locate their solar panels on flat green roof?

 

I have an acquaintance who used this method for their roof, seemingly successfully but would like to hear others experience. 

 

The pros are obviously the lack of penetration into the roof membrane for fixing points but what are the downsides.  What comes to mind is performance in strong winds given the lack of fixings.

 

Cheers

[BotusBuild]

It's all about the ballast you use to hold them down.

I know of someone who followed the "breeze block" method but used the lightweight versions instead of the heavy concrete ones. Fortunately someone heard what they'd done and they got changed PDQ.

My preference would be the plastic bucket kind as this reduces chance of wind getting under the panels and lifting them up. Heavy ballast still required obviously

[DamonHD]

16kWp on a school roof many years ago - all fine.  Largely survived building works and some being shuffled to an entirely new roof also.

 

https://www.earth.org.uk/solar-powered-schools.html

[DamonHD]

To add: being the H&S governor too, I did ask for additional steel fixings / ropes to the edge of roof surfaces to further reduce the risk of takeoff or at least stuff sliding on to kids below, but I don't think there was any evidence of anything shifting in even quite high winds.

 

The panels were initially on frames with ballast weights.  I think that on the new roof trays may have been used in part, but it is the ballast that is doing most of the ... uh ... heavy work... as suggested above, AFAIK.

[mjc55]

I wonder if there is any way of working out how much ballast is required?

[DamonHD]

There are standard calcs I suspect, likely in part dependent on 99% percentile windspeeds in your area.