1.   Ruberoid made significant use of asbestos as an insulation known as Calcilite, used primarily in roofing products.

2.   The company now makes fiberglass insulation, roofing products, vinyl windows, fiberglass composites and glass-reinforced plastic pipe.

3.   There are, however, some relatively new high-quality roofing products that look like slate but that cost less than the real thing.

4.   Yet another lightweight alternative to slate is StoneCrest, a metal roofing product manufactured by Metalworks, a Pittsburgh company.

5.   Less expensive and sometimes interior roofing products were used in place of specified materials without knowledge of the school district.