Doors made from steel (often called hollow metal doors) are the most common type of door used on exterior construction. They are one of the least expensive options and are virtually maintenance free under normal use. Steel doors also offer some insulating properties and are extremely secure. While steel doors are commonly found on commercial projects, many homeowners are beginning to appreciate this material as well, especially since design selections have increased in recent years. To prevent problems with rust and corrosion, choose galvanized steel doors instead of cold or hot rolled models.
Fiberglass doors are another popular option for exterior use. This material is extremely resistant to moisture and bad weather. It offers strong insulating properties and is nearly as strong and secure as a steel door. Fiberglass is also resistant to the scratches and dents that can damage other materials like wood or metal. This product is generally more expensive than steel and often is harder to find. Many fiberglass door manufacturers produce all units as custom orders, meaning that they take longer to receive and also may cost more. While old fiberglass units had an almost plastic-looking surface, newer models are made to resemble wood grain and texture. While improvements have been made, most people can tell the difference between a fiberglass and wood door without touching the material.
Wood doors are available in a virtually limitless number of colors and designs. Consumers can choose from many different veneers, with oak and mahogany among the most popular. Wood doors also offer customers the chance to choose stains or varnishes to change the look and color of the material. While doors made from wood are generally the most expensive option, they are also the least likely to become damaged, and if they are damaged, they are easy to repair. No other material can match the weight and feel of a quality wood door. While flush models (smooth with no glass) are common in commercial settings, homeowners can choose from stile and rail (panel) doors or units with inlaid glass. The biggest problem with using wood doors on an exterior opening is exposure to moisture and harsh weather. These doors are best used where they will be protected, such as under an awning or porch roof.
The majority of commercial buildings use exterior entrances made from aluminum. This product is popular because of its beautiful shine and modern appeal. Aluminum entrances are also easy to customize with different types of glass and window patterns. This material is very good at withstanding the elements. It will not rust or corrode, and in fact, when exposed to the air, a chemical process takes place that actually hardens and strengthens the surface of the aluminum. This product is used on storefront systems, sliding doors and revolving entrances. While aluminum can be expensive, it is also very durable and long lasting.
The most common specialty construction is fire rating. This means that the door has a special mineral core that helps contain fire and stop it from spreading through the opening. Doors can also be rated for sound transmission. Known as STC doors, these openings have special insulated cores that keep noise from passing through. They are most common in manufacturing and industrial facilities, as well as in residential areas. For security and police buildings, bullet-resistant doors are available. These doors contain special metal and lead cores that can literally stop a bullet from penetrating. When it comes to green construction, consumers can choose from doors made from sustainable wood products, those built using rapidly renewable materials and doors that contain urea-free binding agents. Of course, some of the "greenest" and most interesting exterior doors can be found through construction salvage facilities.