Glue down snow slides

Have a customer with an aluminum shingle roof that wants snow guards, does anyone have any experience with the glue down or self adhering ones?. Ive installed lots of screw down ones, but only on shitty exposed fastener roofs.

Additional note: if the shingles are attached by a single nail through the nailing tab (as in Permalock, Interlock), and the installers did not add additional tabs on the upper lock, the shingle does not have much resistance, as the shingle is being held by ONE nail in a tab that is about 1/2" wide.

The real issue for me would be the strength of the interlock on the shingles. If they are made from 0.019" aluminum (Interlock, permalock, classic), then it doesn't take a lot of pressure to cause the locks to open. Also depends on the local climate conditions - if the snow stays as snow it is less dangerous than if the snow melts/freezes into an ice crust.

I've use Alpine snow guards, and these fail much too easily, with the ice/snow opening up the folded aluminum of the snowguards. I've switched to forged Seiger snowguards which we anchor with 3" steel bolts, and I've seen these pulled out if the bolts didn't go into the roof beams. I've also seen the Seigers broken when the bolts DO go into the beams.

As for the glue-on snowguards, if they are not spread all over the roof, then assuming the glue holds, they will end up pulling out an entire shingle (or more). You have to work it out that the maximum load on each snowstopper is no more than about 30 lbs., and the maximum load on a shingle is not more than 60 lbs.

Yeah im worried about the panels/shingles themselves, whether or not the extra weight of snow sitting on them will destroy them. They are trim coil thickness aluminum, probably around 0.023, and the roofs only 5/12. You can walk on them, so I guess they should be okay. Maybe Ill just double the amount I had planned to spread the weight a bit better.

I've used them for years with no issues as long as there is never more than 4-5'of roof above them. More than that and ice slides will tear them up, and even damage the panels. All over, or not at all is the golden rule with snow guards.