A door is a movable barrier with or without an openable panel. A door covers entrances and exits from buildings, rooms, vehicles, and other enclosures. A door is also used for storing and displaying objects. Doors are usually made of a hard, impervious substance such as wood or metal, but sometimes come in other materials such as glass for additional visibility and transparency.

The most important feature of a door is the opening size. The opening determines the size of the door needed for a specific application. If frames or recesses exist in the surrounding walls, a double door must be installed rather than a single one. When choosing a door, consider the weight of the door and how it will be used. For example, a heavy door should have strong hinges, whereas a glass door should have two hinges for extra support. Pay attention to the aesthetics of the door and how it will be installed. Sometimes, a door must fit into the wall structure rather than have the structure built around it.

There are different types of doors available in the market today. A single door is installed in a fixed position. A single door is best suited for locations where only one entrance to a room or building is in use. An exterior door is attached to the outside of a building, providing an opening for entering and exiting a structure. It is most commonly made of wood, metal or fiberglass. They include hinged door and sliding glass door styles.

A residential door is the most common type of door and varies in style and material. This includes every day, inward-opening door made of a variety of materials. This door is used in homes and commercial settings where privacy is a concern. Another type of door is a double door. A double door is set side-by-side and swings open together. A double door adds architectural detail to your home or office. You can use them at the front door of a house, apartment or office to create a more imposing entrance. A screened sliding glass door is a popular and most efficient way to let in fresh air while keeping out rain and wind. They work well in warmer climates, as they let in a lot of natural light.

A variety of styles are used for a front entry door, including an inward opening door, and an outward opening door. An inward opening door is hinged on one side and swings inward to provide a space between the door and frame when the door is opened. An inward opening door is used for residential applications and exterior installations. An outward opening or French door consists of two panels that open outward onto a porch, patio, or lawn.