Masonry Construction Magazine awarded the Milwaukee City Hall Masonry Project of the Year on February 3, 2010 at the World of Concrete in Las Vegas, NV. This award was not a beauty contest, but an award that focuses on the involvement of the mason in innovative design, construction, materials, cost-savings methods, and environmental consideration. Congratulations to J. P. Cullen & Son’s Masonry Division!
Built in 1897, the Flemish Renaissance Style, Milwaukee City Hall has endured the hardships of time and weather. Restoring City Hall to its inherent architectural glory underscores the abiding utility of masonry as an art form. The building’s exterior restoration includes terra cotta and sandstone repair, replacement, and preservation, as well as fixing or replacing hundreds of thousands of deteriorating bricks.
Terra cotta is the lion’s share of the architectural skin and detailing that covers City Hall. Since 2002, pieces had been falling off the building and onto the sidewalks and streets below. Cullen’s first major task was to completely net the building during the preliminary exterior study phase to deter the falling pieces from hitting cars and passersby.
While carefully preserving existing pieces, Cullen craftsmen anchored and installed new terra cotta sculptures and reliefs, which were recreated to identically match the original design. In some cases, replacing terra cotta elements that had been missing for decades was accomplished by reference to historic photographs of the original design. The 13,000 pieces of terra cotta that needed to be repaired or restored required additional technical training of onsite masons. To create or refurbish the hand-carved details, specially formulated mortars that perform like terra cotta were used to restore to the original appearance and physical characteristics of the building.
Since few manufacturers still produce the pressed brick, sculpted sandstone and ornamental terra cotta that, 100 years ago, were quite common. The sheer quantity of some replacement materials far exceeded typical production of these elements – most of which were handmade due the complexity of the ornamentation.
Craftspeople were carefully selected to ensure that these intricate pieces (which often exceeded several hundred pounds in weight) were created and handset with exacting precision to blend with existing construction.
Innovation was also required on the part of the design professionals as details for reconstruction work were developed. In order to minimize the potential for future water damage to the building materials, the design team created paths for water management behind the masonry face materials. Flashing material used to weep the water out of the assemblies is hidden behind and under the masonry so that the historic appearance of the structure is maintained. In addition, the use of cutting edge tools was the innovative way that we tuckpointed the building when we ran into difficulty meeting the desired quality. The brick joints were half of the width of a typical masonry joint. The tools required were large and unwieldy. The specifications outlined means and methods for removal of old mortar with chisels. Through partnering we redesigned the means and methods to add an electric Fein tool to the acceptable methods of removing mortar from the joints, commonly used for removing caulking. The subcontractor demonstrated its use and it became the standard method for improving the quality of removing mortar from brick joints. The tool also increased the production rates of the removal process.
In addition, the material condition of the existing sandstone included cracks, chips, erosion, and severe deterioration. After a thorough chemical cleaning, Cullen craftsmen replaced severely compromised sandstone with a ‘dutchmen’ – a piece or wedge inserted to hide the fault in a badly made joint – that matched the unique color, texture, and profile of the original design. The sandstone’s repair required specialized training for masons. The correct mixing and deft patching of the sandstone mortar was critical to creating the desired color and texture of the building’s European flair. Additionally, Cullen craftsmen rounded out the sandstone repair with re-tooling of heavily eroded areas to recreate the crisp lines of the original design