Metal Architecture Home

Opening Up to Metal Walk-through Doors

Mcn  Prod Feature  Oct16 2

Learn more about metal doors and how to select them

Historically, metal has been used more as a cladding for protecting wood doors than an independent door material. But in the mid-1800s, contractors began cladding wood doors with steel to protect them from impact by livestock. It wasn't until 1879 that the hollow metal door was invented by the Mesker Door Co., St. Louis. They grew in popularity and have evolved dramatically since then.

"When a building opening calls for any combination of strength, durability or maximum fire resistance, steel doors and frames provide the qualities to meet these needs," says Al Geisthardt, lead engineer at Plyco Corp., Elkhart Lake, Wis. "Valued for their utilitarian function, steel doors continue to develop aesthetic qualities, while accommodating the growing hardware options a door must support."

Metal doors excel in longevity and durability. When correctly installed and maintained, they often last 30 years or longer. A metal door is much stronger⎯especially those made of 20-gauge steel or higher⎯ than either fiberglass or wooden-core doors. Metal doors don't crack, warp or come apart. If a metal door is dented or dinged, fix it with an auto-body repair kit. Coating metal doors with zinc oxide prevents rust and corrosion, and makes them resistant to scratching.

Metal doors can incorporate an internal framework, reinforcements for hardware, and a core material beneath steel skins on each side. The core material varies on desired door performance criteria and can include honeycomb cardboard spacers, polyurethane or polystyrene insulating cores, gypsum for fire doors, and even wood. The steel door skins are attached to the internal core and framework, and are usually joined together around the perimeter of the door panel creating a visible lock seam.

Because its high-density, foam core prevents heat transfer, a metal door is significantly more energy efficient and has more insulating value than wood doors. Efficiency ratings will vary based on overall construction to meet Energy Star certification. Additionally, metal doors outperform other material doors in security, fire rating, sound reduction, vandal resistance and even anti-microbial properties (sanitation).


For Metal Buildings

"Metal walk-through doors are designed specifically to fit into a metal building wall," says Rick Kincy, director of business development and marketing, Dominion Building Products, Houston. "Non-metal building walk-through doors require a framed opening, and extra care to prevent water and air leakage because it can be like fitting a round peg into a square hole."

Joan Smigel, business manager, PDL Building Products, North Olmsted, Ohio, says there are two main characteristics that are unique to a metal building walk-through door. "For preassembled doors, these are the extended front face header and the attached framed opening," she says. "For knockdown doors, these are the depth of the frame combined with having no return at the back edge and butt joints, which allows for the frame to be handed in the field. Both the preassembled and knockdown versions are designed to work specifically with the girts of a metal building, which makes installation very easy."

Geisthardt insists an improperly installed door and its hardware will not function properly, no matter how carefully the door system is tested and specified. But, metal door installation is a relatively simple process. Smigel says to ensure the door operates properly; the door must be installed plum, square and level. "The installer must caulk and screw down thethresholds," he says. "That's really all it takes."

Kincy says squaring the door in the opening is the most common error that leads to almost every swing and hardware problem. "If squaring is done so the door is flush to the frame and all reveals are equal around the door, the door will swing properly and hardware will be aligned," he says. Kyler W. Pope, marketing manager at Plyco Corp., says blocking is a little detail that can make a difference. "Blocking is a spacer around your lockset," he says. "It's used to ensure the door doesn't collapse around the skin when you install the door's hardware. High-density polyethylene blockers will provide support for the skin." Overall, for a successful metal door installation, Pope recommends following the manufacturer's installation instructions, watching for potential trouble spots and taking steps to avoid them before they develop, and correcting a problem at the earliest stage possible.


Classification and Selection

According to the Cleveland-based Steel Door Institute (SDI), standard steel doors are classified in four levels:

• Level 1: 1 3/4 inches and 1 3/8 inches standard duty

• Level 2: 1 3/4 inches heavy duty

• Level 3: 1 3/4 inches extra heavy duty

• Level 4: 1 3/4 inches maximum duty

According to SDI, each of the four levels noted above offer a range of construction models and designs to meet architectural requirements for preference and appearance. The standard steel door construction models are full flush, seamless and, stile and rail. Selecting a metal door for general usage is done by analyzing criteria such as frequency of use, including subjection to and degree of possible abuse. Other criteria to be considered in door selection are: conformance to local building codes and fire code regulations; sound attenuation and/or insulation requirem


Width and Height

The stated size of a door is width by height. Kincy says common open heights can be from: 6 feet, 8 inches up to 10 feet; common single opening widths range from 2 feet up to 4 feet; and common paired openings are 4 feet up to 8 feet.

Smigel advises to discuss metal door opening dimension requirements with a door professional. "For example, the clearance of a 3070 (3 x 7 feet) is not 3 feet or 7 feet," he says. "The dimensions of the rabbit and the thickness of the door create clearances of less than 3 feet in width or 7 feet in height. Another key insight we remind our customers of is the door size as stated does not take into consideration the frame; therefore, the rough openings will be larger than the door size by typically 2 inches on each side of the door as well as the height. Additionally, you need 1/2 inch extra on both the width and the height to get the door into the opening. There are other applications that require other rules of thumb so, again, it is wise to discuss and verify what the rough


Hinges and Handles

Typically, hinges hang metal doors. Five-knuckle or three-knuckle are common choices. Kincy says hinge finishes like US26D are designed for interior use and will rust on an exterior application. "US26D and US32D are good for a lock, mortise lock or panic device," he adds. "Hinges should be powdercoated, stainless steel or bronze-based material to prevent rusting."

While metal door selection should be planned around its use and frequency of use, Smigel believes hinges and handles are especially affected by these factors. "Ever take notice of the back door of a fast food restaurant while at the drive-thru? Many of them have full-surface continuous hinges⎯these are somewhat similar to 'Piano Hinges' that are fully visible. What this tells us is the original door hinges failed, since you typically see full-surface hinges when a door has been retrofitted. Once you start looking, you'll see this quite a bit, even on fairly new facilities. If the end-use involves frequent in-and out (think: taking out the trash, deliveries, etc.), we also recommend kick plates. When it comes to door handles, top factors to consider include use and abuse, as well as security."



Metal door frames are relatively simple. Their various profiles can accommodate a wide range of wall thicknesses and design conditions in both rigid, welded frames and knockdown frames that assemble on-site. A metal door's framing must be considered and the construction of the opening dictates the type of frame.

"There are two main types of frames: masonry and drywall," Smigel says. "Frame sizes not only consider the height and the width, but also the depth of the frame. The depth is typically most critical in drywall applications where you are encasing the wall in the throat of the frame. Your door supplier needs to know the details of the opening to ensure you get the proper frame."

Kincy says a knockdown frame can typically have a width of 4 feet, 1/4 inches; 6 feet, 1/4 inches; 7 feet, 1/4 inches; 8 feet, 1/4 inches; 10 feet, 1/4 inches; or 12 feet, 1/4 inches. Preassembled frames are typically 5 feet, 3/4 inches with a subframe width of either 6, 7, 8, 10 or 12 inches.


Metal Door Storage

Once ordered but before being installed, metal doors should be stored undercover. "To get the best performance out of your door's finish and hardware, be sure to properly store the doors if you are unable to promptly install them," says Smigel.

Place them at least 4 inches above the floor on wood sills or on the floor in a manner that will prevent rust and damage. Avoid using non-vented plastic or canvas shelters which create a humidity chamber. If the wrapper on the door becomes wet, remove the carton immediately. Provide a 1/4-inch space between the metal doors to promote air circulation. Place no more than five doors or welded frames in a group. Small groups not only minimize the likelihood of damage due to excess handling, but also facilitate selection from the group for installation.


Sidebar: Common Steel Door Types

• Cold-rolled steel can be used in most interior applications. Cold-rolled doors are uncoated steel with a factory-applied coat of primer.

• Galvannealed steel is carbon steel coated with an iron-zinc alloy. It is suitable for many interior and exterior applications. Galvannealed provides corrosion protection when combined with a coating of quality prime paint.

• Galvanized steel provides rust protection but has lower adhesion properties for prime or finishpaint.

Information provided by Plyco Corp., Elkhart Lake, Wis.