Mounting to roll roofing?

[createthis]

I've got a simple shed roof with roll roofing (not flat, slightly sloped, measured 8% with an iphone angle meter, or just under 12/2). I want to mount some 12V solar panels to it. What's the best way to do that without causing a leak? My research indicates poking holes in roll roofing pretty much guarantees a leak.

I've seen ballast racking systems, but I'm worried something like that would slide off the roof as it does have a slight slope.

Any other options? I was thinking huge neodymium magnet clamps.

[solarix]

Oversize, 3" x 3" alum L-feet, M1 sealant by Chemlink, 1/4" x 3" SPAX screws, use legs on the back mounts to get proper solar tilt. Done thousands of them with zero leaks

[createthis]

Oversize, 3" x 3" alum L-feet, M1 sealant by Chemlink, 1/4" x 3" SPAX screws, use legs on the back mounts to get proper solar tilt. Done thousands of them with zero leaks

Cool. Where do you get the aluminum L-feet? Got any photos of the setup?

[solarix]

The general trend in the industry is toward "flashed" mounts (which of course don't work on roll roofing) and violate the warranty of any shingle manufacturer I've checked into (pulling nails and breaking the shingle seal) so we stick to L-feet - but the ones you can buy are too small of a footprint in my opinion. They really need to be big enough to comfortably cover any screw holes that miss the framing. So.... we make our own. We also pay a local structural engineer to stamp our mounting system drawings, but easily make that up in savings on standard aluminum material (free delivery from a regional aluminum supplier) and costs about half what the solar mount manufacturers charge for their custom engineered stuff. PM me if you need help.

[createthis]

The general trend in the industry is toward "flashed" mounts (which of course don't work on roll roofing) and violate the warranty of any shingle manufacturer I've checked into (pulling nails and breaking the shingle seal) so we stick to L-feet - but the ones you can buy are too small of a footprint in my opinion. They really need to be big enough to comfortably cover any screw holes that miss the framing. So.... we make our own. We also pay a local structural engineer to stamp our mounting system drawings, but easily make that up in savings on standard aluminum material (free delivery from a regional aluminum supplier) and costs about half what the solar mount manufacturers charge for their custom engineered stuff. PM me if you need help.

I'm just doing this for a one off on a shed roof. I'm familiar to with metal brakes (and using a 2x4 to do the same thing). What do you recommend for metal thickness and foot dimensions? Or is that a trade secret at this point?

I'm just using el-cheapo 100W renogy panels from amazon. They sell an L-foot kit they call a Z-bracket kit: http://www.amazon.com/gp/product/B00BR3KFKE

I have direct access to the underside of the roof, so I can always add additional bracing so the screws bite something substantial. Would there be any problem using something like this?

[solarix]

Those z-brackets have a small footprint - just make your own sheetmetal bracket with a big base. Ours are 3/16 thick alum but could be less. Either use the mounting holes for the panels or put on rails and panels clamps, but don't modify the panels by drilling holes or anything in them or you blow the panel warranty. The key is to make a "compression seal" where there is pressure on the sealant so you are not just relying on its adherence.