By Ken Buchinger
Years ago, installing metal roofs on self-storage facilities was relatively easy. Most buildings were narrow and simple rectangular shapes, and a through- fastened panel such as an "R" panel was used. But times have definitely changed.
Today, self-storage owners are building facilities in or near residential areas, and the need for aesthetic considerations has skyrocketed. Facilities are much more architectural in nature, which usually results in a more complicated roof design. Plus, the industry has switched to standing seam roof systems that require more design consideration and greater skill to install than the "R"-panel roof.
Since Galvalume standing seam roofs typically carry a 20-year perforation warranty, the goal should be to provide the building owner with a roof that will last a minimum of 20 years with minimal maintenance. To accomplish this worthy goal, everyone involved must be committed, including the design professional, roof manufacturer, roofing contractor and owner.
Most multistory facilities are being designed with architectural features such as high side and rake parapets, multilevel roofs and irregular roof surfaces. While these various features add aesthetic value to the project, they also make the roof much more complicated to install. In addition, the design professional should give consideration to the manner in which the roof system will interface with other materials and appurtenances.
Here is a list of items to pay particular attention to when considering a standing seam roof system on a self-storage project:
- Special attention should be given to anything that interrupts the flow of water off the roof, such as roof hatches, air-conditioning units, and especially elevator or stairwell penthouses. In addition, thermal movement must be considered on wider roofs. The panels and the trim must be capable of handling this movement.
- Manufacturer's installation details should be available for standard conditions such as the ridge, hip, valley, eave and rake. The manufacturer should also be able to help with details on special conditions and provide needed information on approved curbs, pipe flashings and other roof-related appurtenances. To help eliminate the potential for problems, comprehensive details for each special condition on the roof should be approved by the roof manufacturer, submitted to the design professional for review, and included in the erection package for the roofing contractor to follow. No detail should be left for the roofing contractor to install as he pleases.
- Never allow the roof panels or trim to come into direct contact with or receive water runoff from lead or copper, as this will cause galvanic corrosion and void the Galvalume perforation warranty. This includes condensate from roof-top air-conditioning units. If masonry or parapet walls are to be installed adjacent to the roof, provide protection to prevent these materials from being dropped onto the roof, which may cause corrosion of the Galvalume metal.
- The roofing contractor must not cut panels with an abrasive blade, as this melts the Galvalume coating and leads to edge rusting. Do not allow a cutoff saw to be used on or near the roof to prevent metal filings from being scattered across the roof. These filings, while hot, will melt into the Galvalume coating and begin rusting.
- The best way to ensure the above recommendations are met is to address them in the project specifications. Specifications should cover: 1) who is to install the specific items (the roofing contractor should be responsible for the installation of items such as curbs, pipe-penetration flashings and crickets); 2) the type of materials to be used; 3) roof manufacturer's approvals; and 4) warranty requirements for the roof and accessory items. If the specifications are thorough, the roofing contractor will have all the information he needs to properly bid the project, the roof installation process will be more efficient and leak problems can be avoided.
- Finally, the owner should be supplied with a maintenance manual to assist him in caring for his roof. Standing seam roofs are "low maintenance" but they are not "no maintenance." In general, the owner should plan to inspect the roof at least twice a year to remove objects thrown on the roof. Steel objects allowed to remain on the roof can cause the roof to rust through. Also, leaves and other debris should be periodically cleaned out of the gutters and off the roof.
Installing a standing seam roof on a building with many architectural features can indeed be challenging. However, with cooperation from each of the parties involved, it can be successfully accomplished, and we all wind up with a successful project and a satisfied owner.
Ken Buchinger is general manager of product development and product installation for Houston-based MBCI, where he is responsible for product testing, improvements and development. He is in charge of the company's Erector Certification Program, which trains erectors in the proper installation techniques of MBCI's metal roofing systems. He is also in charge of inspecting and approving projects for Weathertightness Warranties. MBCI, part of NCI Building Systems, is a manufacturer of metal roofs, walls, soffits and fascias. For more information, visit www.ncilp.com.
Cricket installed by contractor on project with no details.
Roof curb made from sheet metal.
Properly installed cricket at same location.
Roof curb fabricated from aluminum with welded corners.
Air-conditioning condensation causing corrosion to Galvalume roof panel.
Residue dropped on roof during wall installation.
Cutting panels with abrasive blades leads to edge rusting.