COMPOSITION SHINGLE ROOFING  The GreenFasten™ GF1 bracket system is designed to be installed on most new or existing (retrofit) composition shingle roofs for solar panel applications, and is accepted by most major roofing material manufacturers without voiding warranties. The GreenFasten™ GF1 system features a patented, watertight seal compatible with a variety of bracket options. Backed by IAPMO Certification. Watch the install video here.