I'm a landscaper... and I have an unusual project on my hands... One of the barns that I keep my equipment and work out of has a shingle roof. It is on it's last leg and I need to limp it by for another 5 years or so. It is a very large roof (about 15,000 sq feet / 150 square). It only has one layer of shingles on it, so weight shouldn't be an issue since the building code in MI allows up to two layers. I was wondering what you guys thought about spraying seal coat on it to help seal where the shingles are starting to curl and also to protect the gravel coating on the shingles which is beginning to wear away. I understand you can mix sand into the seal coat, which i presume will increase the durability of the mix. As I mentioned earlier, I don't really know much about seal coating and wondered if this is a feasible idea. What are your thoughts? Thanks, Alec.