Just make sure you buy top quality brands; cheap fiberglass is not as strong and will crack in cold weather. Fiberglass is also highly resistant to mold, decay, and rust, which gives it some power advantages over ordinary steel, aluminum, and wood. As far as a security door goes, you can get by with any of these. The main difference lies in aesthetics, not in durability. Interior security door: classificationThe classification of security doors is based on resistance to burglary, i.e. a period of time during which the door can maintain its integrity during attack physicist and chemist at the door. Let's look at the classification of security doors in more detail for you to choose. • CLASS I: This door can be opened by the use of physical force and hand tools (wrecking bar or iron). It provides only basic protection against burglary. The thickness of a door leaf is approximately 20 mm. • CLASS II – Power saws and power drilling tools may be required to open this door. The thickness of a door leaf is not more than 80 mm. • CLASS III – to open this door it is necessary to use heavy duty drilling tools with a power of approximately 2000 W. The thickness of the leaf of a steel door is not less than 120