3 MDF interior doors
Materials of interior doors construction : 3 MDF Interior Doors
Quote from Article entitled Materials of interior doors construction:
Shapes, used in the construction of aluminum doors, can be of two types - warm and cold. A warm aluminum shape in its structure has several sections or chambers, each of which is constructed using a press. Reducing of heat loss is achieved by filling sections of a shape with special polymeric materials which serve as thermal bridge. The construction of a cold shape is simpler; it consists of a single chamber without filling. It is recommended to set up such doors in places where there is no need for heat insulation.
The full version of the article can be found here.