The latest news on New York architecture.

  • The Cathedral Stone Newsletter

    Historic Brick Wall Scheduled for Demolition Saved by Jahn M30 The Cathedral Stone Newsletter, July 2006

    The condominium complex at 241 Eldridge Street was constructed in 1904 in the Lower East Side of Manhattan. Architect Scott Henson was hired by the condominium board to perform a full exterior analysis of the building. The analysis revealed a number of necessary repairs, including brick, window, and terra cotta replacement and repairs, mortar joint cutting and re pointing, as well as the replacement of the roof membrane and cornice. During removal of the parapet walls, the internal conditions of the brickwork and mortar were found to be severely deficient. The back-up masonry was loose laid in many areas with no mortar.

    The failures of this building were directly attributed to the mortar. The mortar used in the original construction of this building consisted of a high-lime content resulting in little or no binding between the mortar and the bricks. The mortar within the walls was loose and powdery. Adverse weather conditions and poor maintenance over the life of the building accelerated the deterioration of the mortar. Several structural engineers were invited to the building to inspect conditions and provide recommendations. The consensus was that the walls required complete reconstruction from the ground up. This solution was prohibitively expensive for the building owners; therefore and extensive search was undertaken for an alternative solution to repair the internal condition of the walls. After the research and testing of many masonry techniques and products, including mechanical pinning, brick repair products and soil consolidation products, Cathedral Stone Products' Jahn M30 Micro Injection Grout was found. When injected, Jahn M30 will travel into the substrate and continue until it flows freely from this port and other ports at the same level. The ports are then sealed using non-staining clay, sealant, or caulk. A series of injection ports must be drilled on the face of the substrate to create a "drill frame." Ports should be drilled in a downward direction. Cathedral Stone Products, Inc. supplied Jahn M30 Injection Grout for a test area. Cathedral Stone Products representatives, including Dan Perakes, conducted the initial testing on the building. A second and larger test was performed to confirm initial results. This test involved injecting the Jahn M30 into specific areas in the walls to determine whether or not the repair process was going to work. Jahn M30 again proved successful. Extensive testing was performed until the correct installation procedures and amounts of grout required were determined to consolidate the existing lose, powdery mortar, to fill the voids between the internal brickwork, and ultimately to provide a structurally stable building. It was originally thought that the cost to replace the exterior walls would be an estimated $1.8 million. The repairs would have to be completed section by section. Because of the success of Jahn M30 the entire project cost was $106,000 saving the owners over $1.6 million. Scott Henson Architects hired Viles Contracting Corporation to complete the repairs. From February 9th to April 22nd, 2005, they drilled 1,435 holes into the building and pumped in 1,280 gallons of the M30 Injection Grout. After 241 Eldridge Street was completed, the project was featured in the NY Times and drew interest from the engineers with the New York City Housing Authority (NYCHA). They wanted to look at the project to see if the repair method was a viable alternative for maintaining their buildings. They met with both Cathedral Stone Representatives as well as Scott Henson. In the summer of 2005, CSP successfully completed Jahn M30 Injection test of the New York City Housing Authority. They are currently monitoring the tests and are considering using the method of restoration for future projects.         Go to Cathedral Stone Newsletter

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  • HABITAT MAGAZINE

    The Wall (Didn’t) Come Tumbling Down A new product solves an old problem. Jody Shen (Additional reporting by Jennifer Wu)

    The sky wasn’t falling but the wall was a definite possibility. That was the dilemma facing 241 Eldridge Street, a 12-unit condominium on Manhattan’s Lower East Side, about two-and-a-half years ago. But thanks to a bit of detective work and the discovery of a product relatively new to the U.S., the board found an affordable answer. It was during routine parapet repair work that the problem was uncovered: the contractor discovered that the internal mortar between the exterior wall’s bricks had turned to sand. Such a finding had not been anticipated in the repair plan because the inspection report the board had commissioned was for the cornice, bulkhead, and fire escapes. The solution seemed dire: spending about $1.8 million to replace the exterior walls, section by section. Even if raising the money were possible (and it would be a strain for the 12 apartment owners however it was done), the financial hardship of large assessments seemed daunting. However, the flip side would have been equally grim: do nothing and risk the walls coming down on their own. That didn’t seem like a great alternative, either. “To have not done anything would have left us with questions, doubt, and possible peril,” explains Robin Schanzenbach, the president of the condo’s five-person board. David Bergman, a board member and professional architect, recalls that his thoughts started to turn to what could shake his building enough to bring it crashing down. Subway vibrations? Nearby construction? An unlikely – but not impossible – Manhattan earthquake? Seeing that completely replacing the building’s walls would be more or less impossible financially, Scott Henson, the building’s architect, started looking for a solution. Possibilities included products used to stabilize dirt at construction sites and a variety of restoration products. He tested HTC, a chemical used to preserve marble statues that had been invented by Norman Weiss, a professor of historic preservation at Columbia University. That solution failed because it needed to interact with oxygen, which couldn’t find its way into the thick walls. Then Henson stumbled upon a product called Jahn M30 Micro-Injection Grout, manufactured by Jahn International of Germany and distributed by Cathedral Stone Products. It had been utilized on large projects in Europe but, according to Dennis Rude, the president of the Hanover, Maryland-based distributor, it had only been used in the U.S. for small jobs, such as the repair of cracking walls. The National Park Service is using it to fix a cornice on the historic Ryan Center at Floyd Bennett Field in Brooklyn. Often, Rude notes, to solidify walls in situations like the one at 241 Eldridge Street, contractors will repoint. According to Henson, repointing was not enough for this project because that would only address the surface, about three-quarters-of-an-inch deep. (The Jahn M30 was ultimately used in conjunction with repointing.) The manufacturer supplied a small amount of Jahn M30 for a test. After that was successful, the condo spent about $10,000 for a larger test, which involved injecting the Jahn M30 into specific areas and opening the walls to see if it worked. That seemed to do the trick, reconsolidating the loose, sandy mortar, and filling the gaps. With the solution in hand, it still wasn’t easy. There was a question of money. Recalls board president Schanzenbach: “There are multiple factors in the finances related to the project. It is fair to say that, with the multiple engineering studies, testing, and architect’s fees, the mortar reconsolidation aspect of the project reached close to $140,000. That amount is lower than it might have been, however, because we had already started on a larger capital project to replace the roof, cornice, and parapets, and do pointing, so some of the major costs – such as scaffolding or the process of preparing extensive bid proposals for contractors – did not have to be incurred. Our active board involvement and the cooperation with the architect and contractor, who were already on the job, also helped keep the costs down.” Funds were used from the building reserve fund to help pay for the work, but more money was needed. According to the president, the unit-owners approved an additional assessment of $100,000. Each owner’s portion of the assessment was based on his or her percentage of ownership in the building. To pay for the assessment, some owners refinanced, while the surging apartment prices in New York enabled others to take out home equity loans. And, thanks to a multi-year financing plan, still others were able to pay in installments. After a short newspaper article on the repairs appeared in the spring, everyone involved, from Weiss – who called it a possible solution for “hundreds, maybe thousands of buildings” – to the distributor, began hearing from people in similar situations seeking help. Seven engineers from the New York City Housing Authority wanted to inspect the project to determine if the product and process would be effective in repairing aging public housing. They visited the job site and queried Henson and a representative from Cathedral Stone. They seemed impressed, Henson recalls, and said they planned to perform a test on some of their buildings. As for the condo’s board: after repairs on the sidewalk in front are finished, they will have spent $500,000 to finish a building revamp that began with a “cornice subcommittee” years ago and, with the wall repair, may have saved the building. There is still the dream of one day creating a roof deck, but for now, Bergman is happy that the “sky” isn’t in danger of falling anymore. Says he, with a sigh: “We can breathe for a while.”     Go to HABITAT MAGAZINE

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