Sealing strip of soft foam

A method of producing a sealing strip roll, comprising:

• providing a web of a soft, open-cell foam;
• impregnating the foam to delay the recovery of the foam alter its compression and subsequent release;
• rolling up the foam web onto a wide roll and cutting the wide roll into narrow sealing strip rolls;
• unwinding each sealing strip roll and applying and bonding a thin, closed layer of a flexible or film-like material with a thickness of 0.002-0.5 mm to at least one side surface of the foam;
• and
• rolling up the foam provided with the thin closed layer into a sealing strip roll, in which the foam is present in a partially compressed state.