Polyurethane foam for installation of the door frame.
What gap is needed between door, floor and frame : Polyurethane Foam For Installation Of The Door Frame.
Quote from Article entitled What gap is needed between door, floor and frame:
Further operation of the door structure depends on how well gaps will be calculated and put. Under the influence of moisture door can expand and then problems with its functionality cannot be avoided. Also, too large gap hinders reliable fixing of doors in the closed position.
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