Longtime Erie employer GAF Materials Corporation is closing its doors for good. One hundred and fifty workers will be out of work when the plant officially shuts down Friday. Company officials explained to employees that a decline in demand for roofing materials produced poor numbers forcing the plant to close up shop. GAF told us it is moving towards consolidating operations with another GAF facility located outside the Erie area. The Erie Bayfront has been home to GAF for the past 120 years. It has been a key player in the area`s manufacturing industry.