We purchased a home with asbestos shingles. We would like to replace it with a stucco exterior. A contractor said that he could simply attach galvanized metal to the house then stucco outside of that. Is there any health hazard in this? Or should the asbestos shingles first be removed? This turns out to be a costly alternative so we would prefer to have the stucco put over the shingles, but because we have two young children, our first priority is safety.