Solar mounts on an EPDM flat roof

[Paw85]

Hi,

I’m looking to install solar mounts on an EPDM flat garage roof. Because I want to install my PV panels flat, I’ve decided to go with L brackets that have EPDM gaskets and screws with EPDM washers. Rails will be fixed to these brackets. I’m wondering if it makes sense to add additional sealant, like CT1 or something similar, between the roof membrane, gasket, and bracket, or if it’s sufficient to just bolt them as they are. I’ve tested both solutions for the past three weeks, and they both performed well. Any advice would be welcome.

Thanks.

 

[fourtytwo]

In my case I have a GRP roof and no way did I want to pierce it and invalidate the warranty so I used ballasted mounting instead.

 

[matlob]

I now that some campervans just have these glued on the roof so may be an option as long as it won't react to the rubber.

Are all walls on the garage seen?

 

[Paw85]

In my case I have a GRP roof and no way did I want to pierce it and invalidate the warranty so I used ballasted mounting instead.

I have the same concern, but I prefer a flat installation and believe that fixing the brackets will give me better peace of mind in windy weather.

 

[freddiemercurystwin]

@matlob Or rip off chunks of the membrane in a gale?

 

[Paw85]

I now that some campervans just have these glued on the roof so may be an option as long as it won't react to the rubber.

Are all walls on the garage seen?

Yes, it’s a detached garage.

 

[fourtytwo]

You can calculate wind load here then subtract your panel and mounting structure weight to find required ballast, then check your garage roof structure is capable of supporting that weight all quite simple. Flat panels will loose a lot compared to even a moderate slope of 10-15degrees that is possible and still be within PD limits of 500mm projection AIRC with care.