How is front door insulated?

Operating conditions of the front door of a private house and the entrance door in the apartment are very different. The impact of environmental factors on the front door of the house requires serious consideration when it comes toinsulating materials. Lets consider the possible options for insulating the door.

Insulation for front metal door.

Corrugated cardboard. It is difficult to attribute this material to the class of sound and thermal insulations. It can only be used as a filler without any claims for additional functionality. The only advantage of this material is a low cost of corrugated board.

Corrugated cardboard

Mineral wool. This insulation retains the heat very well and provides good sound insulation. The only drawback is that mineral wool loses its thermal insulation properties when used in the places with high humidity.

Mineral wool

Styrofoam. This insulation has a sufficiently high rate of protect against the cold and extraneous sounds. But over time, the styrofoam begins to crumble. It is especially the case if the front metal door separates the house from the street, and not from the warm vestibule.


Expanded polystyrene. This material is made by extrusion and therefore has a single structure. Expanded polystyrene does not absorb moisture, does not crumble and consequenly, does not deform. This material eight times stronger than the previous one and its absorption of moisture is lower by 65%.

Expanded polystyrene

Foam. Low thermal conductivity is an advantage that this material has. However, foam is able to absorb odors. In the conditions of low humidity, the foam can dry out and crumble, which reduces its thermal and sound insulating properties.


Insulation that Steel Line uses in the entrance doors for apartments.

For insulation of entrance doors for apartments Steel Line uses mineral wool "Knauf" (Germany). Innovative ECOSE®technology does not use formaldehyde and acrylic chemical compounds during manufacturing process. Insulation «Knauf» does not corrode, does not let the cold air inside, effectively suppresses noise and vibration.

Steel Line also uses special fixing technology that places the mineral wool Knauf within the door and door box coming from the top. This way we exclude sagging, which makes it possible to isolate all the open cavities inside the front door. The insulation stays in place the entire service life of the product.

Insulation of Steel Line  doors for the house.

The doors installed in the house/street boarder require much more serious approach to the process of insulation of the door and the door box. Modern insulating materials most suitable for outdoor insulation are polystyrene and foamed polyethylene called Porilex. They retain heat and maintain heat-shielding properties over the entire service life.

For the insulation of doors in 80S series, Steel Line uses high density polystyrene. The material is resistant to severe frosts, retains insulating properties and is very stable even when exposed to low temperatures (down to -60 ° C).

The door box in series 80S is insulated with Porilex. The thickness of this material is 1 cm, which equals 15 cm of brick wall when it comes to retaining the heat.

Doors in 100S series are insulated with multi-layer insulation system. Special heat reflective material (thermal mirror) combined with air layer creates "thermos effect". Thus, improving the thermal insulation of the door by more than 30 %.

Expanded polystyrene does not absorb condensate and moisture from the air, does not lose its heat-shielding properties, and does not settle with time.

The system of multi-layer insulation of the door box using Porilex imitates the design of multi-chamber plastic window profiles. The first layer is placed in a box in the form of tightly coiled helix. The second layer is placed as a whole cloth around the perimeter of the box.

Additional sealing of joints and elements of the door box excludes moisture and protects the front door to the house from corrosion.


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