Ornamental metal fencing is used in thousands of communities across the country with most being constructed with steel tube posts, rails, and spindles. Fannie Mae has listed steel fencing as having an estimated useful life of 50 years. Most communities have historically experienced significantly less useful lives than 50 years, with some only getting 20 years out of their fence. So, the question is, “How do we get a steel fence that lasts?” Proper detailing and installation of ornamental fencing is paramount for long-term performance. While some municipalities have set-back and fence size requirements, most items that affect long-term fence performance are in the hands of the installer. Let’s start with the base, or footer foundation, for the fence system. If you are looking for a foundation with a life cycle that is in alignment with the expected life of the fence elements themselves, SBSA recommends a concrete footer system.
Depending on the size of the project, it may be more economical to have ready-mixed concrete delivered. Keep in mind that typical minimum orders are one cubic yard, which equals 27-cubic-feet (or 46,656-cubic-inches). The footer should terminate above grade and should be finished with the slope away from the post. This will prevent moisture from collecting at the metal post base and causing premature corrosion of the metal. The steel tube posts, rails, and spindles should have weep systems strategically placed to drain moisture that gets into the system out; this includes condensation. Keep in mind that interiors of the steel fence members are not coated and are immediately susceptible to corrosion. The weeps should be placed on the various members in a downward fashion as to allow air in and keep moisture out. The steel fence members should be coated prior to usage, and that coating needs to be proactively maintained. The Society for Protective Coating (SSPC) has specific directions to maintaining steel fencing. Determining correct coating for the conditions present will provide the longest life of the coating.
Proper surface preparation of ornamental fencing is imperative for the coating to adhere and protect the metal. Surface preparation can include pretreatments to remove corrosion, or portions of the previous coating. In these cases, the chemicals used in the pretreatments may require time for the reactions to occur, prior to the application of the primer coating. No matter what corrosion resistant coating is used, following the manufacturer’s specifications and installation instructions is a must. These will identify conditions, specifications, and curing times for the products. Just because your coating feels dry, it may not be cured yet. This affects the maintenance and care of areas around the newly coated fence. Consult with your landscaping staff so that the fence has proper time to cure to its full strength. This may mean that some typical landscaping operations in the immediate area need to be postponed until curing is complete. The ornamental fencing must be cyclically inspected, as corrosion is fast and progressive. Any damage should be addressed as soon as possible to prevent further deterioration of the coating and steel itself. Following these steps should keep your fence on track for its 50-year estimated useful life, and prevent surprises to your community’s budget.