Abstract: This disclosure relates to a tool for use in the installation of rock wool or fiberglass insulation in residential and commercial buildings. The tool includes first and second tubular body members affixed to each other in an adjustable and telescoping relationship, a paddle member affixed to the first tubular body member, a blade member affixed to the second tubular body member, and a spring actuated tubular safety sheath covering the blade member during use of the rock wool or fiberglass installation tool. The adjustable length of the tool permits enhanced flexibility during the installation of rock wool or fiberglass insulation. The paddle and blade members provide increased utility and convenience to workmen, and the spring actuated safety sheath minimizes the risk of injuries to individuals during use of the tool.