The metal panels are rarely a source of moisture intrusion, unless there are openings from surface corrosion. Leaks in these systems predominantly occur at panel terminations and flashings. Therefore, it is important that the design and installation of the materials at these vulnerable points are properly completed.
The use of lightweight concrete as a roof decking and insulation system has expanded in the past five years. Increased usage can be attributed to the recent industry-wide insulation shortages and delamination deficiencies. The increase can also be attributed to the economic and environmental advantages that lightweight insulating concrete (LWIC) provides in roof assemblies. The increased use in specific regions of the country has spawned new technology to meet the demands of the market from the economic and environmental standpoints. Advances in pumping equipment and mixing ratios have provided materials that are consistent in compressive strength and density.
EPDM systems have been on the United States commercial roofing market since the 1960s. Their widespread use began in the 1980s, and the technology has developed a favorable market share in the industry since that time. Their rise in market share correlated with the energy crisis in the United States during the 1970s (which drove the price of bitumen up due to higher oil prices), the development boom of the 1980s and increasing roofing labor shortages. The size of the membrane sheets (typically 20 feet by 100 feet) allowed contractors to install the systems with less labor and virtually no equipment. These factors quickly contributed to their widespread acceptance, as they were more economical to install over the labor-intensive, equipment-laden built-up roof systems.
The most visible of all roof-related problems is moisture intrusion into the facility -- i.e., the roof leak. Roof leaks do not necessarily indicate total roof system failure. They indicate that there is a failure point within the system. That failure point must be corrected prior to extensive damage to the roof as a system. The extent of the damage to the components of the system caused by the leak will have a greater bearing on the overall system failure.
The successful construction of a low-slope roof system requires adherence to proper application methods. A roofing contractor can enhance the probability of success by administering assurance methods that can be followed by project managers (foremen, superintendents, etc.). There are certain criteria that are required for the proper application of all low-slope roof systems. Best practice methods can be employed to ensure that these application methods are followed on a continual basis throughout the course of the project.
All successful roof projects require that the installers adhere to proper application methods. Improper workmanship contributes to a decrease in the roof systems service life. All types of roof systems - both steep-slope and low-slope applications - are prone to potential workmanship errors. In the case of steep-slope shingle applications, there are a number of common mistakes that should be avoided to ensure a long service life. A successful roofing project and satisfied client can be achieved if these common mistakes can be avoided in the field.
The recent increase in storm frequency - particularly in high-velocity winds - throughout the United States is prompting changes in the roofing industry. Attachment procedures for all roof systems, both steep slope and low slope, are being scrutinized, and code changes are imminent.
Environmental regulations and insurance requirements are playing an increasing role in the types of materials and the methods of application that we will employ in the roofing industry in the near future.