When the main cell house building at the historic Alcatraz Federal Penitentiary was constructed in 1910-1912, prison workers mixed salt water from the surrounding San Francisco Bay and brick rubble in the concrete support beams. Coupled with the island's extreme weather conditions, the large, cast-in-place concrete support beams in the original Citadel and basement shower room areas that support the main cellblock structures began to deteriorate and fail, posing major structural damage to the historic building.

The Citadel was part of the original structure and dates back to the Civil War era. Its masonry walls support the massive concrete beams carrying the load of the penitentiary located above. The shower room is located on the same level as the Citadel, but is separated by earthen fill and has walk-in access at a lower level of the structure.

The general contractor on the project hired Western Specialty Contractors – San Francisco, CA Branch for the $3.6 million structural repair project after the original contract team defaulted on the job, pushing the project over a year behind schedule. Restoration work on the structure was also required to bring the structure up to California's seismic codes for earthquakes. Once a contract was approved, Western crews quickly mobilized to the job site to complete the job.

Western's scope of work focused on the Citadel and shower room areas and included replacing beams and masonry that support the cell house floor, installing engineered shoring, repairing the cell house structural floor, performing non-structural patching and masonry, repairing salvageable beams to protect them from further deterioration and installing a cathodic protection system to prevent deterioration of the metal support. All work on the project would be completed at night to avoid disrupting public tours of the historic landmark during the day.

Like any historic restoration project, there were challenges. One of the main challenges faced by Western's crews was controlling the amount of dust generated during the demolition process.

“Dust control was a major challenge, especially considering the amount of work that was happening in such a small area with poor circulation,” said San Francisco Branch Manager Tony Lieder. “When Western took over the project, we spent approximately two to three weeks just cleaning the site and removing debris left by the previous contractor. Often the dust was so bad, each shift would have to stop working about an hour early every night just to clean up. One of our first tasks was to find a way to engineer out this issue and increase productivity.”

Western crews found a two-tier solution for controlling the dust – creating mini-containment zones and using large, customized air scrubbers.

“When performing the demo, we created mini-containment zones in each location, as well as used localized air scrubbers and vacuum attachments for our equipment when appropriate. For the main work areas outside the containment areas, we obtained several large, customized air scrubbers that had a much greater capacity than what was commercially available. The improvements in the dust control were dramatic.”

Another challenge on the project was transporting materials to and from the island. The only available transportation option was a barge.

“Our materials had to be light enough for our on-site forklift to handle and we commonly had to break down pallets of material in order to lighten the loads or partially fill dumpsters when returning debris,” Lieder said. “Loading and unloading the barge also depended on the schedule of the tides. If the tide was too low, we couldn't load or unload equipment. If we ever had equipment breakdowns, we would have to scramble during the day to get everything resolved and back to the boat that night.”

Despite the challenges, Western crews were able to successfully complete the project within nine months.


Mazza Castle

Built in 1908 in Pacifica, California by San Francisco Attorney Henry Harrison McCloskey for his wife Emily, the mysterious Mazza Castle had seen its share of owners during its stormy history, as well as coastal exposure which had reduced its steel reinforcing to piles of rust and left its cast concrete stones cracked and damaged. The Sam Mazza Foundation, which currently owns the castle, hired Western to restore and preserve the historic building from future damage.

The experts at Western began by repairing the damaged cast stone and replacing its concrete headers and sills with three custom-blend patch mixes. Crews also replaced, reinforced and repaired the “rope joint” grout with a custom-made jointing tool.

Once the repairs were complete, Western cleaned the building and applied a penetrating masonry sealer to restore its exterior. Additional phases are required to ensure the complete restoration of this historical structure.

201 Mission Street

Although new silicone sealant was installed on this building just 10 years ago, leaks have been a continual problem. Inspections determined that failing sealant covers about 10% of the facade.

To solve the problem Western replaced the sealant and completed frequent, intense, and uncompromising inspections to insure the solution had been solved.

Western worked closely with Jones Lang LaSalle to coordinate noisy work around tenant schedules to minimize noise disruptions. Grinding the joints between the precast panels creates noise and dust. There are no interior wall panels to deaden the noise or minimize the dust. The inside perimeter of the windows were taped and sacrificial backer rod was installed on the exterior, which prevented most of the dust from coming in.

Ongoing water leaks that had plagued the building for years were resolved. The project was completed with minimal disruption to the tenants.

Building 62 Loading Dock

Located at a federal government facility, the Lawrence Berkeley National Laboratory falls under the federal OSHA regulations. The safety requirements are very strict. Western Specialty Contractors was selected for a concrete restoration project at the facility because of it’s safety record and the ability of it’s crew to operate under tight restrictions.

A large liquid nitrogen holding tank is located on the loading dock of Building 62. Several times a day, lab researchers visit the dock to fill the individual tanks for their labs. Often times during the filling process, LN leaks out hitting the concrete deck. This exposure creates an immediate freeze/thaw condition causing cracks and spalls to develop. The weight of the filled tanks (between 300 to 500 pounds), rolling across the docks caused further damage to the concrete surface.

Western craftsmen removed the spalled and damaged concrete. SIKA SLV55 penetrating sealer was applied into the cracks. The replacement material chosen was SIKA 2500 repair mortar. The use of this material allowed the crew to place an epoxy coating on the loading dock within four hours of installation. The coating used was SIKA 52 loaded with sand to provide a slip-resistant surface.

Both the owners and researchers are happy with the result. No longer will the lab technicians have to fight through the maze of cracks and spalled concrete.


Olympic Club Swimming Pool

Western Specialty Contractors was contracted to remove the existing plaster surface of the swimming pool, as well as the underlaying waterproof membrane. And then install a new CIM 1000 waterproofing membrane. Upon demolition of the plaster and membrane, the crew uncovered many areas on the topping slab that were spalling and showing signs of corroded reinforcing steel. Care had to be taken during the demolition process due to intricate detail work and painting that had been completed in the pool hall.


555 9th Street

The parking garage at 555 9th Street had experienced a number of water leakage problems. Crosspoint Realty, the management company, contacted Western Specialty Contractors to assess the problems. After reviewing the situation, it was decided to split the work into three phases.

In phase one, Western recommended to replace failed caulking and expansion joints. Most of the water problems were occurring in these areas. The metal cover plate over the expansion joint had suffered a great deal of damage due to steel wheel traffic and exposure to fork lifts. Western worked with standard sheet metal to design a new metal expansion joint cover. The new heavier aluminum cover plates will not only protect the expansion joint, but the exterior caulk joint as well. The first phase of the project also included stucco repairs. Phase two will begin in 2005 and involves the application of an Isoflex heavy-duty vehicular traffic coating.

Since the project has been completed, the water problems have been eliminated.