I would only worry about the wind blowing them away. as long as they are fastened down I suspect you are OK. However, I am not sure of what you have. a picture might help.

I doubt they're going to blow away, I practically got a hernia today unloading the latest batch from the pickup, and I do plan to fasten them down. They're the insulated glass modules taken out of door walls: Two sheets of tempered glass, about 28"x80", glued together with a spacer around the edge, to make a 5/8" thick unit.

My chief concern is that the edge of the unit is going to be exposed to weathering, and I don't know how the sealant will cope with that.

I'll sketch my general plans and post a link to them sometime in the coming week.

Here's how I plan to mount the thermopane units on the roof:

Here is a link that might be useful: {{gwi:307339}}