Exterior doors are often considered a business card of the house. Therefore, they should not only be nice and blend in well with the body of the building, but also muffle sounds, protect against cold and constitute a difficult obstacle for burglars.
Exterior doors are made of wood, metal, PVC, or fiberglass, but these do not appear in single-family homes.
Wooden doors have been the most popular for centuries. Today, their frames are made of laminated wood, which prevents deformation under the influence of moisture (warping). They are made of pine, spruce and deciduous national wood (oak, ash) and exotic (meranti, mahogany). The wing can be reinforced with steel sheet hidden inside. Its surface can be smooth or decorated with moldings or coffers. Wooden doors are characterized by good sound and thermal insulation as well as low thermal expansion. Their disadvantage is sensitivity to changes in humidity.
The metal door is a steel or aluminum frame filled with thermal insulation material and shielded on both sides with panels, usually of the same metal. These can still be covered with decorative veneer.
The skeleton of steel doors (anti-burglar doors have such a structure) are sections, stiffened with bars (profiled sheet metal, truss) and filled with insulating polyurethane foam, mineral wool or foamed polystyrene. Sheathing is steel sheet, thick chipboard or waterproof plywood, finished with veneer or laminate, imitating wood. Steel doors with increased burglary resistance are resistant to balancing tests, cuts, etc. The price for high strength is a significant weight. Typical, non-burglary models can be lighter than wooden ones.
Aluminum doors have frames of two or three-chamber profiles and insulation, like steel. The frame is usually filled with aluminum panels, the surface of which can be anodized, powder painted, finished with veneer. They are durable, durable and stiff. They have better sound absorption than wooden ones, but are easily damaged by mechanical damage, e.g. dents.
Plastic doors are made of multi-chamber profiles of hardened PVC, reinforced with galvanized steel or aluminum inserts. Between the profiles there is a filling made of smooth or extruded plastic plates, often combined with a warming layer of polyurethane foam. Such doors are colored at the material production stage or finished with veneer. They are light, easy to install and quite cheap. However, a damaged wing cannot be repaired. At most, you can mask minor damage with a special paste. Unlike wooden doors, they do not require maintenance.
Exterior doors, ordinary or for special tasks?
In order for the door to fulfill its task, it must have appropriate parameters, such as: thermal conductivity U, fire protection, sound insulation, mechanical resistance and anti-burglary protection. Some places require better properties than those offered by average doors. Such places include, for example, companies, the homes of wealthy people, buildings close to busy routes and airports, energy-efficient and passive houses. In such situations, ordinary external doors are not enough.