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Prepainted Galvalume� sheet roof adds new life to 105-year-old courthouse.The century-old Bell County Courthouse in Belton, Texas, is a fine example of classic-style architecture. But it had a problem. The general condition of the four-story building was excellent. But the asbestos-shingled roof had developed some serious leaks. There was no question that the building had to be reroofed. The project was complicated by the fact that this landmark structure was hemmed in by several buildings and trees. This posed a challenge to the contractor. The problem was how to lift the new roofing materials onto the roof in such a way as to avoid power lines and tree branches. Larry Rector of Central Texas Structures, said, "A crane would have been too expensive. Also, we would have had to position it across the street, which would have blocked access to the detention unit and additional courts. It just wasn't practical." Roofing RequirementsThe material selected for the reroofing had to be strong yet light enough to be lifted by hand. Durability and ease of maintenance of the finished roof were very important considerations, also. And so was color. The roofing material had to match the 105-year-old copper gutters and trim. The contractor's familiarity with ASC Pacific's Klip Rib concealed fastener architectural roof panel system led them to select it for the project. The panels, which are UL90 rated, are produced from Bethlehem Steel's 24 gage prepainted Galvalume� sheet with a Weathered Copper PVF2 fluorocarbon coating. The variety of color options available greatly simplified the task of finding the appropriate weathered copper color that matched that of the existing copper trim and gutters. Another important consideration was deciding what to do with the existing asbestos shingle roofing. One option was to remove it, double bag the shingles, then ship them off to a controlled disposal site. However, after further consideration, it was decided it would be less hazardous to place the metal panels directly over the shingles, effectively sealing them from the atmosphere. Each panel, some as long as 33 ft, 6 in., was hoisted up to the 4-story-high roof with the aid of a pulley system. To accommodate the concealed fasteners, the contractor removed the ridge shingles and used 1/4-in. hand rubber shims to align each shingle with the one above it. By covering rather than removing the existing shingles, the total installed job cost $4.50 per square foot. The roof was installed in January 1989. The benefits of aluminum and zincTwenty-four years of actual outdoor exposure tests in a variety of atmospheric environments clearly demonstrate that bare Galvalume sheet exhibits an excellent combination of corrosion-resistance properties. Galvalume is a registered trademark of BIEC International, Inc. The substrate is a quality cold-rolled sheet to which is applied a highly corrosion-resistant hot-dip metallic coating consisting of 55% aluminum, 43.4% zinc, and 1.6% silicon, nominal percentage by weight. This results in a sheet that offers the best protective features characteristic of aluminum and zinc: the barrier protection and long life of aluminum and the sacrificial or galvanic protection of zinc at cut or sheared edges. To this extremely durable substrate are added corrosion resistant chemical pretreatments, specially formulated, high-performance primers and any one of a number of durable, attractive finishes including polyesters, silicone polyesters and fluorocarbons. Each paint system is formulated to insure superior long-term performance at sheared edges, as well as at flat, formed and paint-damaged areas. Galvalume sheet, bare or prepainted, has become the preferred material for metal roofing applications the world over. Bethlehem's reputation for standing behind the product was another reason for the materials selection. Bethlehem invented and developed the product in the mid-60s and offers a warranty on the substrate not to rupture, fail structurally, or perforate due to corrosion for a period of twenty years and six months. Standard paint warranties are also offered. Bell County Courthouse now has a roof that is not only attractive, economical, and weather-tight, but one that will also provide many years of trouble-free service. |
