This means as the earth moves while the house tries to remain in place, there is less weight on the roof to react in the opposite direction. The principle is somewhat like centrifugal force whereby the heavier the weight being swung on the end of a rope, the more force that would be exerted on the rope itself. Less weight on the roof thus puts less strain on the supporting structural wall system during an earthquake. In addition, steel roofing creates a strong structural membrane across the entire roof that resists both tensile and compressive forces, providing much greater strength for the structural envelope of the house. Concrete is strong in compression but not tension.
Steel is stronger, pound for pound, and thus less weight is used for steel roofing.
Steel roofing has aesthetic advantages, being able to mimic many other forms of roofing, and enjoys the longest practical service life. Pa. on the Ohio line appx. 30 miles south of lake Erie Thanks. Thank you for your inquiry. Thank you for your inquiry.