[Expert advice] How to install an interior door. Step-by-step instructions!

Tools and equipment
Masking tape, PU foam sealant, foam gun, corner clamps, adjustable braces, gloves, safety glasses, screwdrivers, tape measure, utility knife, spirit level

1. First of all, read the door manufacturer's instructions before the installation. Doors are made in a great many models, and the installation sequence can differ from one to another.
Before installing the door, check that the size of the door matches the size of the door opening.

2. When measuring the door opening, make sure its corners are square and its walls are plumb.
If the deviation from the vertical or the horizontal is more than 2 cm, the geometry of the opening has to be corrected.

3. The gap between the door frame and the wall has to be 1 to 3 cm.
Wider joints call for extension jambs.

4. To adjust the position of the door frame and keep it from distorting, always use wedges in the gap between the wall and the frame.

5. Before the foam is applied, level the door and make sure it opens easily.
The door has to be flush with the walls of the room, so that the door trim can be fitted.

6. Three wooden braces or dedicated frame spreaders have to be fitted inside the door frame.
The braces go at the level of the hinges and of the lock.

7. Before the foam is applied, the door opening and the door frame have to be cleaned of dirt and dust.
The cleaned surfaces have to be misted with water before the foam goes on.

8. The foam has to be applied between the wall and the frame at the wedge positions, on both sides — usually in 6 places.
Do not use too much foam: allow for post-expansion.

9. The foam sets in 20 minutes and is fully polymerized in 24 hours.
The braces should not be removed earlier than 24 hours after application.