Now you can start mounting a new box. As a rule, the box for interior doors consists of three parts, two side beams and one upper. Boxes of four parts should be used for bathrooms and toilets. Where the fourth is the lower beam. After installing the box, such works as eliminating unwanted clearance and cracks between the design of the box and the wall are carried out. After which all this skillfully hides under cashing. Now we have to install the canopies and attach the canvas itself. Having performed all the necessary work, we can only check the door for functionality. If the door and all its components are installed correctly, it will be easy to open and close.