Post Gauges (11, 14)
Railing systems can fail if the post gauge is too thin, even if made of tubular steel. It is important to work with the railing manufacturer to ensure the tube size and the post gauge specified is appropriate for the application and use intended.
Spacing and Line of Sight: Steel vs. Other Materials
The spacing between rails is a key building code requirement linked to the health, safety, and welfare of building occupants. Complicating matters, the International Residential Code (IRC) regulates single-family dwellings, and the International Building Code (IBC) regulates multifamily and commercial dwellings. Additionally, different codes apply to railing systems installed on stairs vs. decks. Prefabricated railing systems can make meeting these various code requirements easier.
Open stairs greater than 30 inches in height are required to have a guard installed on the open side, as well as a handrail. These rails must be at least 34 inches high, from the nosing of the stair treads. The spacing between the rails must prevent a 43/8-inch sphere from passing through, except space where the stair riser, stair tread, and bottom edge of the rail meet, in which case, 6 inches is the minimum. As specified by R311.5.6.3 in the IRC, the top edge of the handrail must be between 34 and 38 inches above the nosing of the stair tread, and the handgrip must provide 11/2-inch space between the handrail and the guardrail or wall.
Decks that are designed to be higher than 30 inches above grade are required by code to have a guardrail; however, in cases where a building professional chooses to install a guardrail on a deck below 30 inches, they still must meet the code requirements. For homeowners, the code requirements for single-family detached homes can be found in the IRC, which requires a railing to be a minimum of 36 inches from deck to the top of the rail. However, the railings can exceed that height as long as all other code requirements have been met. The code is flexible regarding infill materials, but mandates that the spacing between the materials (e.g., rails, glass panels, and rods) does not include openings large enough to pass a 4-inch diameter sphere through.
Multifamily dwellings and commercial properties are subject to the codes provided in the IBC. Because many apartments and commercial buildings extend multiple stories in height, the guard railing height requirements are higher than for single-family buildings. The IBC height requirement for guardrails is a minimum 42 inches, from the finished floor to the top of the rail. However, as long as all other code requirements are met, the railing can exceed that height. These railings have the same infill opening spacing requirements as railings for single-family homes.
Line of Sight
When architects design a porch or deck for a house that has a view, the last thing they want to do is obscure that view with a bulky railing system. With a stainless steel railing system, cable infill can provide a seamless connection between the built and natural environments. As noted earlier, thin cables can often become “invisible” from a distance, thus giving the illusion of an unobstructed view, and yet provide the necessary safety for the building occupants.
Cable infill can withstand the wear and tear of different weather throughout the year, and because it is corrosive resistant, it requires minimal maintenance. While glass infill can keep the line of sight clear, it does risk being coated in dirt, and thus will require frequent cleaning. In comparison to materials such as wood or aluminum, stainless steel provides options for clear sight lines (as noted above) along with strength.
Aesthetic Benefits of Stainless Steel
Stainless steel is one of the most forgiving materials when it comes to a reliable aesthetic. The material resists corrosion and is very easy to maintain, whether used for railing systems or home appliances. The aesthetic element stems primarily from how the steel is finished, whether that finish achieves a highly polished marine look, a refined brushed-satin look, or adds color and texture through a powder coating.
Proper Care & Maintenance
This highly durable material is called “stainless” steel and not “stain-free” steel. When specifying stainless steel for an exterior application, and especially when the location of the project is an environment that is in close proximity to a mixture of highly corrosive elements (salt, chlorines, heavy industry, etc.), periodic cleaning of the railings will improve both the appearance and the performance of the product.
Finishing Options
The Specialty Steel Industry of North America (SSINA) provides on its website a list of architectural finishes for stainless steel used for railings. The most common finishes are: 180 grit polish, finer polished finishes (240, 280, and 320 grit), and buffed finishes.
180-grit polish is the most common polish finish for railings, and virtually all railing components made of stainless steel can be polished. For example, welded products or components can be polished, as can different shapes of steel tubing (e.g., round, square, or rectangular).
For projects that emphasize the aesthetic element of stainless steel, or where a smoother finish is needed, finer polished finishes (240, 280, and 320 grit) can be used. These finer finishes are more reflective than lower-grit finishes, and the finished product is smoother and easier to clean; finer grit finishes also resist corrosion better than low-grit finishes.
Buffed finishes tend to be selected for aesthetic purposes when a highly polished look is preferred, or when corrosion resistance and easy cleaning are desired. This finishing process is done mechanically, usually with a 320-grit, and then followed with a buffing process.
A final finishing option for railing systems is a powder coat. This type of finish is great for adding a pop of color to a railing system, while also helping improve the product’s durability. Powder finishes are applied as a dry powder and then hardened under heat, and the treatment can provide an appearance similar to paint, but it is considerably more durable. Moreover, the treatment process is less toxic than paint, and it can withstand extreme temperatures. This final point can be very useful when it comes to hot weather and railing systems in that a good powder coat can help reduce the heat retention on the top rails. In climates with hot summers, such a finish can ensure that the railing is safe to touch, and thus functional even during hot weather.