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Concrete repair scheduled for residential towers Project will cost $1 million
(Above) On the roof of the west residential tower late Thursday morning, workers prepare for concrete repair that will be done from suspended scaffolds. (Below) A worker climbs over the fence on the 65th floor roof deck. (Click on images to view larger versions.)
20-Sep-09 – Repair of Marina City’s generous concrete along the exterior of both residential towers will begin this week. In 2006 and December 2007, engineers inspected the concrete and identified some problem areas, but residential property manager David Gantt says none of the problems are serious and the repair work is “routine maintenance.” The main focus of the project, he says, “is to comply with the city’s request to repair small sections of the exterior concrete.” With sidewalk canopy barricades protecting pedestrians on Dearborn Street from any falling debris, workers will move up and down the towers from four “swing stage” suspension scaffolds. “The process to repair [and] replace the concrete is quite involved and requires cutting open the areas of weakened concrete and drilling down to the rebar,” wrote Gantt, referring to the steel bars that reinforce concrete. “The rebar is then sandblasted, sealed with epoxy, then covered with a specialized adhesive-added concrete.”
(Above) The concrete when it was new. This photo from Portland Cement Association shows construction of the west residential tower in 1962. Click on image to view larger version. For a short time in the 1960s, Marina City was the tallest structure made of reinforced concrete. In the early 1990s, Marina Towers Condominium Association spent $1.7 million over three years to repair concrete and repaint balconies and vertical surfaces. In March 2008, the condo association estimated it would cost $2 million over three years for exterior repairs, including railings which have already been repaired, and the membrane that covers the concrete slab on each balcony. MTCA says it has the money to pay for repairs and a special assessment will not be necessary. Since then, however, MTCA has decided to charge unit owners for membrane replacement. It will cost $1,250 for each full balcony and $900 for a half-balcony. All apartments at Marina City have a full balcony. One-bedroom units have an additional half-balcony and two-bedroom units have one and a half additional balconies. According to Gantt, the polyurethane membrane, while waterproof, will not level the balcony floor and prevent “ponding,” the accumulation of small ponds of water. The membrane is flexible and durable, says Gantt. “The membrane can be liquefied and a top coat could be put on that membrane should a future post replacement or barbecue fire mar the membrane finish. Although the membranes carry a five-year warranty, many of the membranes installed 15 years ago are still bonded tenaciously to the deck.” Past president, treasurer critical of MTCA plan Former MTCA treasurer Mark Ulaszek, who owns multiple units and lives in the west tower, says there are “way too many unanswered questions.” He is concerned that too much time has elapsed since the 2006 and 2007 inspections. “Concrete can deteriorate quite a bit over two or three years of summer heat…and freezing winters,” he says. “Just last year, a piece of concrete fell off the rim of the balcony above me, exposing the rebar. It looked fine last year.”
Former MTCA president Dr. Martin Flynn shares Ulaszek’s concern that the last inspections of the concrete might not have caught all the problems. “A visual inspection in no way allows the MTCA to know the exact problem areas. Only by sounding the concrete during a critical inspection can this claim be made.” Sounding is done by striking the concrete surface with a steel rod or ball-peen hammer. The resulting ring will be clear in good concrete and dull in concrete that has deteriorated. Gantt told Marina City Online on Monday that sounding was done to all of the balconies on both towers. “We dropped each tier and echo tested. A schematic drawing was created and each patch is noted on the drawing. Because we did such thorough testing the price is nearly guaranteed.” The testing was done by Wiss, Janney, Elstner Associates, Inc., a structural engineering firm with 19 offices across the U.S., and then peer reviewed, which is common, by CTL Group, an engineering consulting firm based in Skokie, Illinois. Flynn, meanwhile, does not agree unit owners should have to pay for repair of their balconies. “Every owner is equally affected by balcony deterioration, hence, the repairs should be done in a coordinated manner and paid for out of reserves.” He points out that balconies, while under the control of the individual unit owner, are still a “limited common element,” under the authority of the condominium association.
Flynn quotes from MTCA governing documents that appear to prohibit the condo association from charging unit owners for balcony repair. “Notwithstanding the status of the balconies as Limited Common Elements,” says the rules, “the periodic painting and other maintenance of the surfaces of the balconies in conjunction with the painting and maintenance of the exterior of the buildings shall be a common expense.” The repair of the membranes as planned, says Flynn, is “cosmetic” and does not address the underlying ponding issue. When water accumulates, he says, it can lead to faster deterioration of the concrete. “Owners should realize that these degradations to the facade reduce property values as the towers become less and less architecturally important, except as perhaps a footnote in a textbook.” Ponding an ongoing issue at Marina City According to residential property manager David Gantt, when the concrete was finished in the early 1960s, an error with how floor drains were placed resulted in uneven balcony surfaces. Marina City architect Bertrand Goldberg, he suspects, “must have had a fit.” Over the past few years, Gantt says experiments have been done to see how the ponding could be fixed. “We tried to see if it would be possible to create a little [water collection] trench to the drain but the engineers determined that the rebar would be too close to the…trench. The rebar would then rust. We tried lightweight concrete and determined that…was not entirely acceptable as the drains were still too high. The cost would be over $12,000 per balcony…That’s $12,000 times 1,248 balconies.” The project will cost $1,023,500, according to the October MTCA newsletter, awarded to Quality Restorations, Inc. Work will start on the west side of the west residential tower, followed by the east side of the west tower next year and then the west side of the east tower. Finally, by December 2010, work is tentatively scheduled to be completed on the east side of the east tower. Says Gantt, “All in all, these are considered minor repairs but nothing is minor when you have so many balconies, posts, pickets and dividers.”
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