I am a college student that is a member of the Engineers without Borders organization. I, along with a groups of other students, are going to Guatemala this spring to install a solor electric system for a school in the mountainous highlands. The school was built with a corrugated metal roof and we need to put 1" hollow tube braces through itfor the solar panel mount. Cutting the holes and installing the solar mounting structure will be the easy part but im having a hard time coming up with good long lasting soution to patching holes around the 1"HT. I am a mechanical engineer so i dont know much about the roofing. I have attached a picture of the roof so you can get an idea of what it is. Thank you for your help. Our final design is due this week so any input would be greatly appreciated.