Before you install the door you need to perform other works.
At what stage of repair interior doors are installed : Before You Install The Door You Need To Perform Other Works.
Quote from Article entitled At what stage of repair interior doors are installed:
If the door is placed at the stage, when floor is ready, then a wooden door is enough to leave a 5mm gap between the door leaf and the floor, and a 3 mm gap is enough to the plastic one.
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