Spring hinges, for example, help close doors automatically and keep them closed. This can contribute to improved security and even climate control in a building. Weld on hinges are used in heavier-duty applications in which hinges are used to suspend heavy doors. Strap hinges feature long metal plates that extend across most of the width of a door, often for decorative purposes.
Important considerations when choosing a door hinge are the strength of the hinge, its visual appearance and its handedness (the direction it swings). Door hinges may be left-handed or right-handed, or they may work both ways. The most common type of door hinge is called a butt hinge. These basic hinges are composed of two machined plates joined by a pin.
Generally, two butt or three butt hinges are used per door. One type of flush hinge is the tee hinge, a hinge installed on the surface of the door that is shaped like the letter T. Tee hinges are available in plain and heavy-duty versions as well as decorative varieties. Another type of door hinge is called a butterfly hinge. These are also placed on the surface of a door.
Butterfly hinges are available in a number of decorative styles and finishes. The continuous hinge, also called a piano hinge, is more commonly used for pianos and toolboxes, but they can also be used for doors. Strap hinges are among the most ornate door hinge options; they extend over the entire width of a door and can be embellished with flourishes and other decorative designs.