For outdoor jobs such as building a deck, installing windows, or constructing a fence, the fasteners you use can make or break your project. This guide explores various exterior fasteners, including stainless steel, galvanized, aluminum and coated nails, screws, and staples, to help you choose the best outdoor fastener that extends the life of your structure.
Rain, snow, high humidity (especially in coastal areas), and UV rays from sunlight can cause fasteners to pit and corrode, compromising their holding power and the structural integrity of your project. Exterior fasteners are specially manufactured to help keep your structure standing against the elements.
Interior fasteners are typically made of uncoated, polished steel. They are affordable and provide a long-lasting hold – as long as they’re not exposed to harsh environments. Exterior fasteners are made to resist the elements , either by using corrosion-resistant metals or through special platings and coatings. The raw materials used and additional manufacturing steps are the reason exterior fasteners typically cost more than indoor fasteners, but that upfront investment can add decades to the life of your structure.
When exposed to air, aluminum forms a protective oxide layer that prevents corrosion. This quality makes aluminum fasteners great for outdoor applications that require rust resistance. They are commonly used for light- to medium-load applications like doors, windows, or siding. Aluminum fasteners are durable, especially in drier climates, but they may not be robust enough for more demanding applications in harsher environments.
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Stainless steel is engineered for rust resistance, making stainless nails, screws, and staples ideal for heavy-duty jobs that require more holding power than aluminum. There are two types of stainless steel fasteners commonly used for outdoor projects: stainless steel 304 and stainless steel 316.
Stainless steel 304 fasteners contain nickel and chromium, providing excellent corrosion resistance and making them suitable for drier climates. Stainless steel 316, also known as “marine grade” stainless steel, adds molybdenum to the mix, which provides superior protection against saltwater and humidity. These fasteners are highly recommended for coastal environments.
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Galvanized fasteners are coated with zinc to resist corrosion. They are less costly than stainless steel, but unlike stainless steel, they are not naturally rust resistant if the zinc coating chips or wears away. Hot-dipped galvanized fasteners have a thicker zinc coating than electro-galvanized fasteners, providing better rust protection and longevity.
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Coated fasteners – typically screws – are similar to galvanized fasteners in that a coating is applied that protects the metal beneath from water intrusion. Screws coated with ceramics and polymers, such as black phosphate or epoxy, are especially useful for projects that require high corrosion resistance and a strong hold without the cost of stainless steel.
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When selecting fasteners for your outdoor project, consider the materials you are working with, the climate, and the expected lifespan of the structure. Aluminum, stainless steel, galvanized, and coated fasteners each offer unique benefits that cater to different project needs. Choosing the right fastener is essential to ensure your outdoor project remains durable and weather-resistant for years to come.
SENCO’s exterior finish coatings feature a proprietary multi-layer coating technology designed to prevent corrosion. The combination of layers provides exceptional resistance to rust and corrosion with a clean finish surface, reduced drive torque, and variety of color choices. A spec sheet is available upon request.