Exterior Door Requirements

Heavy Duty

• An exterior door must stand up to the elements. Unlike hall and closet doors, which are subjected only to interior temperatures and conditions, exterior doors face rain, snow, wind, debris, heat and cold. This means a door facing the outside requires extra weight and material that will not warp significantly with temperature change. Many exterior doors are made of or lined with metal. Exterior doors made from wood often have metal storm doors in front of them to reduce damage and weathering.

Locks

• Bathroom doors have locks, but they are designed merely as a notice to those who would enter. Because the bathroom door is light-duty, a heavy-duty lock is unnecessary. An exterior door is fitted with locks that keep out intruders. Door locks are made from solid cast metal. Also, a deadbolt or secondary lock provides the added protection of a solid metal bar that pushes through into the door jamb.

Total Coverage

• Hall, closet and bathroom doors provide a barrier between rooms but need not provide full coverage since the environment in one room is not very different from the environment in the rest of the home. Because of this, a small gap between the door and the floor is common and allows airflow underneath the door. If the same gap existed with exterior doors, there would be a loss of air conditioning stability and rodents or bats might even get inside. Instead, exterior doors reach all the way down to a plate that seals the inside of the house from outside air and human and nonhuman intruders. Weather stripping is sometimes used to prevent leaks from the inside air conditioning to the outdoors.

Insulation

• The exterior door requires extra protection against elements. While a reinforced exterior is part of this, insulating material is also necessary. As with walls and rooftops, insulation helps keep the heat or cold inside a house while the temperature outside is drastically different. Doors are insulated either by materials such as wood or by foam inserted into the door.