Restoring The Egg’s Shell
The next time you skip work for a game of golf, consider this: It is quite possible that the grips on your golf clubs, your golf balls and even parts of your get-away vehicle’s interior all contain the same polymers as that roofing material you are leaving behind – whether you work with asphalt shingles, modified bitumen or elastomeric coatings.
Kraton Polymers, Houston, formerly part of the Royal Dutch/Shell Group of Companies, invented styrenic block copolymers back in the 1960s. These polymers are found in a vast array of products including adhesives, sealants, coatings, roads, and of course, roofing.
So what does this mean to you, the roofer? Bob Kluttz, senior research chemist at Kraton Polymers, attempted to give us a brief yet simple chemistry lesson. “In SBCs, part of the molecule is polystyrene, which is hard, and part is rubber, which is elastic.” When mixed with various substances, the resulting compounds take on these characteristics, showing good fatigue resistance as well as high elasticity.
“Think of a sponge soaking up water,” Kluttz explains. The polymer is the sponge; the other component is the water. When the polymer is added to hot bitumen, for example, the polymer swells up to nine times its original volume, causing the rubbery matrix to take up a substantial proportion of the total volume, and thus changing the performance of the bitumen.
How about a real world example? “Asphalt in felts can either be too gooey or too hard. The polymer makes it stronger, more elastic and more flexible,” says Kluttz.
Most membranes, felts and asphalt coatings, and even some asphalt shingles, use styrene butadiene styrene. “The SBS has a good balance of properties, but not outstanding reflectivity,” explains Kluttz. Thus, membranes are typically coated with gravel. But in coatings that are designed to be the top layer, manufacturers need something that is more thermally stable and resists UV degradation. This situation calls for the Kraton G styrene-ethylene/butylene-styrene (SEBS) product line. “When properly formulated, coatings made with SEBS can withstand direct UV exposure,” says Kluttz.
A Good FitThe key, of course, is a product that is properly formulated. Truco Inc., Cleveland, offers Eterna-Seal thermoplastic rubber coatings that are compatible with a number of roof types, though their performance over Hypalon®, metal, BUR and spray polyurethane foam is the most established over time.
“We have a reputation for being a conservative company,” says Chris Hoskins, president of Truco. “We like to go through lab procedures, do testing on smaller roofs for about five to seven years, and then sell a product.” For example, Truco has found that its coating works well over Stevens Roofing Systems’ CSPE (Hypalon). On the other hand, “We don’t recommend using our coating over PVC,” says Hoskins. “It has active plasticizers that increase the embrittlement of the sheet. We don’t want to reduce the membrane’s service life.”
Metal is also a good fit for Truco’s coating, and occasionally SPF. “We really have to pick our spots and ask: ‘Is this really a good value?’ Our product works especially well on single-ply that has been applied over a BUR,” says Hoskins. “We can keep the owner out of a tear-off of multiple roofs. With a 300,000-square-foot roof, the price spread can be close to seven figures — that’s a huge savings that we can provide.” He continues, “But it’s a timing issue — you have to get to the membrane before it’s too far gone.”
Hoskins points out that the SEBS resin is solvent-based, with high-reflectivity and wash-off resistance, meaning it can be used in a larger weather calendar. Crews don’t have to worry about a late-afternoon thunderstorm popping up to wash off their hard work.
Truco’s product is not a breathable coating, which makes wet insulation a concern. “Before application we require an infrared scan,” says Hoskins. And it follows that the company is carefully chooses contractors to work with. “We prefer to work with people who are experienced,” says Hoskins. Truco has a program for certifying contractors, but it will work with others depending on the project and whether or not a field rep can oversee the job.
Under the Governor’s Watchful EyeWhat do you do when you are an architect with the State of New York Office of General Services, Design and Construction, and a building that you are responsible for — a high-profile building that is clearly visible from Gov. Pataki’s office — needs a new roof? Well, if you are Assistant Architect John Morelli, you talk to Rick Franklin, a Truco representative.
Morelli had worked with Franklin in 2000 when the State Education Building in Albany needed restoration. Built in the early 1900s, the structure had a copper panel roof that was showing a lot of wear and tear. The state didn’t want to spend the money necessary to replace the roof, so Franklin, then an independent consultant, suggested coating it with Truco’s Eterna-Seal product in a patina green color. Impressed with the product’s aesthetic qualities and 10-year warranty, the state chose to go with Truco.
“The warranty was very important,” says Morelli, “and it looks great; it still looks like a copper roof.” This good experience turned Morelli on to Truco coatings as he considered what to do about The Egg, otherwise known as the Performing Arts Center.
The Egg is situated right off the Hudson River in Empire State Plaza. The Plaza was created during Gov. Rockefeller’s urban renewal, complete with a concourse and reflecting pools. The capitol is at one end of the plaza and the governor’s mansion is just off the other end.
Construction of The Egg began in 1966 and was completed in 1978. According to its Web site, “Though it appears to sit on the main platform, the stem that holds The Egg actually goes down through six stories deep into the earth. The Egg keeps its shape by wearing a girdle, a heavily reinforced concrete beam that was poured along with the rest of the shell. This beam helps transmit The Egg’s weight onto the supporting pedestal.” The structure houses two theatres, the Lewis A. Sawyer Theatre, seating 450, and the Kitty Carlisle Hart theatre, seating 982. The larger theatre has a 10,000-square-foot lounge area.
The Egg’s roof is oval-shaped and is roughly 276 feet by 202 feet, with more than 50,000 square feet of roof. The system is composed of a concrete deck, followed by liquid waterproofing, then pressure-treated 2x4s and styrofoam insulation in a grid pattern covered by plywood. On top of this is a glued-on neoprene sheet with a Hypalon coating.
The roof needs recoating about every 10 years. Nearing the end of that period, the grid pattern of plywood and 2x4s was starting to show through the roof. Morelli first consulted with Roof Scan Inc., a firm that had previous experience with The Egg. Roof Scan helped Morelli evaluate the condition of the roof and provided an infrared survey to determine if sub-surface moisture, leaks or other water damage was present. The company played a pivotal role in selecting the elastomeric roof coating for the project.
As with the reroofing of the education building, Morelli was looking for long-term performance and a 10-year warranty for The Egg. In addition, “The Truco product has 50-percent solids, is VOC-compliant, with minimal chalking,” says Morelli. “And we wanted the roof to be bright white.” Morelli also cites high tensile strength and good elongation properties as requirements for the new coating. In addition, the “or equal” specs called for a contractor who had performed a certain number of installations. “I got all the things I wanted,” says Morelli, “It was like Christmas.”
The JobJames A. Edgar Roofing and Sheetmetal Inc., Scotia, N.Y., won the bid to reroof The Egg. The company is working with Coatings Systems Co. Inc., West Milford, N.J., on the project.
Edgar Roofing has been in business since 1980, doing almost everything – BUR, single-ply, two-component sprayed waterproofing and coatings. “We don’t usually do public work,” explains Jim Edgar, president of Edgar Roofing. “We do heavy industrial – paper mills, power plants. It’s dangerous work, but profitable.” However, Edgar was interested in The Egg since it is a high-profile building.
Edgar Roofing bid the last time The Egg needed reroofing, but the company did not get the job. This time, however, they were familiar with the building, and had worked with Truco over the years. “We are confident in them,” says Edgar. “The people at the company are great to work with. Technical support is great – they are very knowledgeable. They are careful about what their product goes on. This is good for us. We’re not big on new things that haven’t been proven. And we want a manufacturer behind us if there is a problem. I’ve known Chris Hoskins for more than 12 years.”
Peter Osowski, president of Coatings Systems, agrees that Truco provides tremendous backing for contractors. Coatings Systems has been in business for 10 years and Osowski has worked with Truco for the past six years. Coatings Systems also sprays other elastomeric coatings, polyureas, foam insulation, epoxies and polyurethanes. “Truco is easy to work with and it’s the best value for the customers,” says Osowski. “I don’t worry when I use it; it has a proven track record.”
According to Osowski, the specs for The Egg are simple: Prepare the roof and apply the coating system. In regard to prepping the roof, Osowski says, “It only involved minor work as far as repairing the delaminated substrate. Some plywood needed to be refastened and some areas of the membrane patched.”
The next step was to wash the roof and set up safety systems. According to Edgar, there are about nine anchor points on the roof to attach a 5-inch steel cable, lanyards and body harnesses. “The building is like an egg in an egg cup – turned sideways,” Edgar explains. “From the low part of the egg down to the plaza is about 80 to 90 feet. So everyone is tied off all the time.” As many as eight workers have been on the job at one time, but that number has now gone down to five. “We can’t have that many people working up there,” Edgar explains, “It’s not safe.”
In addition to spraying two coats of Eterna-Seal, the crew from Edgar Roofing and Coatings Systems lined the roof’s gutters with polyester fabric and seam sealer from Truco. When spraying the roof, workers will use a Titan 8900 300-psi hydraulic sprayer.
“There is usually a good 15-mph breeze blowing, but it doesn’t affect the coating,” says Edgar. “When we spray, we are keeping the pressure down to the bare minimum it takes for atomization so we can avoid overspray.”
“It’s a solvent-based coating, so thunderstorms won’t wash it off,” adds Osowski. “If it was an acrylic, the Hudson River would turn white.”
A Hard Egg to CrackThe biggest challenge to working on The Egg has to do with its location. “Once I do the design/bid portion of a project, it gets turned over to Construction Services. They run the job meetings and lay down the law,” says Morelli. “We had a job meeting back in April and they laid down some tough working conditions. There are shows at The Egg constantly during the summer and events on The Plaza, so there are some days the contractors won’t be allowed to work. There are also 9-11 security issues. But the contractors were great about it, and very accommodating.”
Work on the egg began at the beginning of June 2002. In theory, it should take about four to six weeks to complete. At press time, however, with all of the dates the contractors aren’t able to work, Edgar predicted that the job would last longer. “But we’ll work it out,” says Edgar. “We are working with good people, they understand and are running interference with all of the competing interests involved. This is definitely the most challenging part of the job. The last time it was recoated, they used paint brushes and rollers and it took nine months to finish.”
Osowski adds that working in the Empire State Plaza, with tens of thousands of people walking around, is another challenge. “We have to maintain a presence on the ground to make sure pedestrians are safe.” Not to mention the fact that the state offices all right there. “We’re in the looking glass,” he says.