Central Marin Sanitation Agency, Administration Building

SGH’s work included conducting an initial survey of the existing roof system to document its configuration and developing a design that included:

• Removing and replacing the metal panel roofing with a new assembly to match the original
• Preserving the existing wood sheathing and adding gypsum decking to meet fire code requirements
• Installing new waterproofing over the decking with integrated flashing at transitions between roofing planes, at the chimney, and around the skylight
• Designing new wood framing to support four small skylights that the agency wanted to replace a large wood-framed one on the eastern side of the building

SGH served as the designer of record for the project and provided detailed construction plans and specifications, including demolition requirements, framing and skylight materials and installation information, and roofing materials and attachment details. We collaborated with the agency to sequence the work and allow the public facility to remain fully operational during construction. SGH also provided construction administration services, including reviewing contractor submittals, visiting the site to observe demolition and installation of the new roofing assembly, helping address field conditions, and witnessing water testing of the new skylights to validate performance.