Exterior door

Fixing an exterior door and insulating with OCF

Necessary materials and instruments: shims, optional spacers, masking tape, gloves and goggles, 1K polyurethane foam, optional fixing screws, optional 2K polyurethane foam, knife, plumb, screwdriver, hammer, optional foam applicator. 

There are different types of doors available with their advantages and disadvantages. The best door for you is the one, answering best to the qualities you find most important would it be aesthetics, durability, energy efficiency or security. Most of all, before starting with door installation, check the door manufacturer's instructions. There is a wide variety of different models available which installation can be rather different, depending on the door model and searched properties. Exterior doors are especially affected by environmental factors and only proper installation can ensure long-term service. Before starting installation check the suitability of the door dimensions to the opening. Best is to leave approximately 3 cm between the frame and while measuring the opening, check if the corners of the door opening are at 90º, walls plumb and floor straight. If they are not right-angled and plumb, the walls and floor (basis) should be remodeled. Remember to check both sides of the door! Fix any problems in this phase.




  • The opening prepared for door installation should be clean of loose particles and dust. Sensitive surfaces or floors should be protected from PU stains by masking with adhesive tapes or canvas cover.
  • Place the frame inside the opening and center that in the final position. The space between the door frame and the wall must be between 1 to 3 cm. For wider joints the fixing has to be adapted accordingly and PU foam sealing built up gradually by layers.
  • The door frame should be aligned in vertical and horizontal position using a level. Re-check and ensure that the door is plumb and straight. Using shims the alignment can be adjusted and the door preliminarily fixed into the opening. The space between the walls and door frame must not decrease during the installation process, keeping it at approximately 3 cm width.
  • The spacers must be positioned at the height of both hinges and the lock. Measure the width inside the doorframe at the top, middle and bottom. The distance should be the same everywhere. Check both top corners, they should be right-angled.
  • In case of the door with sturdy frame (check manufacturer's instructions!) the spacers may be skipped as the frame can bear the curing pressure of the expanding foam. Plumb and straight fixing a door into the opening with the help of shims and mechanical fixing with the help of special screws is a must for such working technique.
  • After the door frame is installed in the right position, one last check should be made. Install the door wing and close it to check if the space between the door and the jamb is even from top to the bottom. If the gap is uneven the whole process of alignment should be redone until the alignment is right.


  • Before applying PU foam the door should be leveled and checked whether it opens properly. It has to be aligned with the walls of the room, as to be able to install door trims.
  • After the alignment is finished the door frame must be fixed to the wall to avoid movement either with the door frame spacer or the above mentioned shims which are placed into the joint, according to the installation technique selected and following manufacturer’s instructions.
  • The door frame and the bottom should be protected with paper or masking tape in order to prevent soiling by possibly falling down froth pieces.
  • External door frame must be fixed mechanically with the special screws according to the manufacturer's instructions.
  • Check and make necessary adjustments to the locking system to ensure proper working of the lock.

Insulating and sealing

  • After either mechanical fixation is fully carried out, the void between the door frame and walls will be filled with 1K PU foam. DO NOT remove spacers in this phase!
  • Foam sparingly the 1K foam into the void. Check the respective product description for joint filling level as for some products necessary expanding space has to be leaved.
  • At dry conditions the foam needs additional moisture. Moisturize the surface of the foam slightly with water by an atomizer. Do not use too much water! Moistening of the surfaces where the foam is applied further improves the adhesion.
  • The spacers must not be removed before the foam is fully cured, wait at least 3 h, depending the ambient conditions. Within the rooms with very dry air the 24 h waiting time may be needed.


The overexpanded foam can be cut by using a cutter earliest after 1 hour, depending on the application conditions and humidity levels. The cutting surface of the foam must be protected from UV radiation and covered with plaster, mortar or similar.

Choose the correct product according to the below guidelines and depending on the volume of the void to be filled.

Recommended products

Makroflex STD - installation door with the help of spacers

Makroflex PRO - insulation of the joint of mechanically fixed door

Makroflex Premium PRO - insulation of the joint of mechanically fixed door