It all depends on the thickness of the steel. This point deserves special attention. If we express the thickness in thousandths of an inch, higher is better. If expressed in gauge, the lower the number, the thicker the steel. For instance, 20 gauge steel is thicker than 24 gauge. Ask for the thickness of the steel on both sides, exterior and interior. Another important consideration is the type of impact. If a car hits a garage door at 6 mph, it will heavily damage the door, whether it is covered in steel or aluminum.