For more information, click on an NRCA document below about roof system maintenance. "Maintenance: The Key to Long-term Roof Performance" "Roof warranties" Manual for Inspection and Maintenance of Built-Up and Polymer-modified Bitumen Roof Systems: A Guide for Building Owners Manual for Inspection and Maintenance of Sprayed Polyurethane Foam-based Roof Systems: A Guide For Building Owners Manual for Inspection and Maintenance of Low-slope Structural Metal Panel Roof Assemblies: A Guide for Building Owners Manual for Inspection and Maintenance of Steep-slope Architectural Metal Panel Roof Assemblies: A Guide for Building Owners Repair Manual for Low-slope Membrane Roof Systems