Retrofitting for Solar Panels

One of the owners in our strata wants to investigate putting solar panels on our 35 year old tar and gravel roof. We are part of a group of five older condos in this small area. How can we find out if this safe for the building, whether it is in compliance with possible restrictive covenants and worth it in savings (he thinks the solar power could be sold back to BC Hydro). The manufacturer is coming to speak to the strata council but we would like another point of view.