Title
City Hall Roof Issues
Memorandum
In April, 2007, staff began a study of the roof structures on the City Hall building because of deteriorating conditions and water leaks. This memorandum is an update to that review process. There are two roofing structures to address. These are the main building roof, located above the 6th and 7th (mechanical penthouse) floors, and the promenade deck, which acts as the roof for the 1st floor. While the replacement of both roof structures is necessary, the timing and method of this work has been difficult to establish because of the fluidity of the master plan and the conceptual design process related to the site renovation project.
Main Building Roof
The overall condition of this roof is poor and replacement is necessary. This roof is less affected by the changes being proposed for the Courts/PD facility and the renovations to the Larcom Building. Replacement should be planned for FY 10 or FY 11, possibly in conjunction with other work being done on the site. The City may wish to consider a 'green' roof system or utilize this roof as a collector for stormwater that can be reused throughout the site. Interior roof drains and piping should also be upgraded at the time of replacement. Additionally, the portion of this roof that is above the 7th floor (mechanical penthouse) should not be replaced until the asbestos has been abated from the 7th floor ceiling. Roof replacement over the 7th floor would significantly disturb the asbestos material sprayed on the ceiling. Since the asbestos on the 6th floor has already been abated, this is not an issue for that portion of the roof. Water leaks from this roof are not as severe as the promenade deck and can be minimized on a short-term basis through patching.
Promenade Deck
The promenade deck, which acts as the roof for the first floor, is in very poor condition. The appropriate repair of this surface will be at significant cost and a sizeable undertaking. Much of this surface may be addressed through the Courts/PD facility construction, Larcom Phase I renovations and overall site improvements. Based on current Phase 1 plans, only the north section of the deck will still need repair. To minimize potential damage to the basement and first floor renovations being done as part of Phase 1, it is important to have the north deck section repaired prior to completion of that work. Completing this work in conjunction with the other work on the promenade deck is the most practical solution. This work would likely be done in FY 09 and FY 10.
In the interim, water leaks are being actively managed through repairs and a series of containment vessels and bladders. In May, air quality testing was undertaken in the building, with special focus on the basement and first floor, and no elevated levels of molds, mildew or other harmful particulates was detected. Maintenance staff has also been working to clean and repair roof drains to minimize leakage.
An immediate improvement that staff is recommending would include covering the tops of the planters that are attached to the building between the second and third floors. These planters leak water into the building. A sloped metal roof would be placed over the top of each planter and sealed to keep water from entering the planters and leaking into the building. This improvement would only be visible from the third floor. A secondary improvement that staff will soon explore includes the concrete planters on the promenade deck. These planters are also thought to be a source of leaks and may need to be removed and have the deck surface below them repaired. Another option, though not recommended by maintenance staff, includes recoating the entire promenade deck surface at a cost between $75,000 and $100,000. This was done seven years ago and, as history has shown us, does not stop the water leaks. With the Phase 1 improvements being considered at the Larcom Building, a permanent fix is necessary.
The City will continue to make repairs and interior improvements to minimize water leaks while actively managing those leaks as they occur. Air quality testing will be completed twice yearly to ensure the safety of our employees and the public that utilizes our facility. Staff will be compiling cost estimates in conjunction with the upcoming Capital Improvement Plan preparation to ensure that the entire promenade deck is adequately repaired prior to the completion of Phase 1 renovations to the Larcom Building. Plans and funding should also be structured for the replacement of the main building roof in FY 10 or FY 11.
Staff
Prepared by: Matthew J. Kulhanek, Fleet & Facility Manager
Reviewed by: Sue F. McCormick, Public Services Area Administrator
Approved by: Roger W. Fraser, City Administrator