Corrugated means folded to produce ridges and grooves. The purpose of corrugating is to increase the tensile strength of a material. The first corrugated metal roofing materials used was galvanized iron and was referred to by the initials CGI (corrugated galvanized iron). The corrugating process increased the bending strength of the galvanized iron in one direction, perpendicular to the grooves. When used on a roof CGI sheets overlap by at least a couple corrugations to insure waterproofing. Later other materials were galvanized for roofing, and strengthened in the same way.
Advantages of Corrugated Metal Roofing
Corrugated metal roofs were, and still are, popular for many reasons.
- Corrugated metal roofs will last 2 to 3 times the length of asphalt shingled roofs.
- Large building or buildings that may experience large snow accumulation particularly benefit from a lightweight yet strong metal roof
- Additionally metal roofs shed snow more easily than other types of roofs.
- Corrugated metal roofs will resist the harmful effects of nature better than roofs made from other materials.
- Practically imperious to fire and hail
- These roofs will harmlessly dissipate the electric charge of a lightning strike and stand up to high winds better than asphalt shingles.
- Their ability to withstand the ravages of nature make any building beneath them less expensive to insure.
- When combined with a high reflectivity coating, these roofs can cut air conditions cost by reflecting instead of absorbing heat from the sun.
- There is less wasted material; the roofing material comes in sheets which can be ordered individually.
- The metal can be recycled saving material and energy as well as reducing waste sent to landfills.
- These roofs also afford a flexibility that other roofing materials cannot. A corrugated metal roof can be installed over an existing roof, a solid substrata or even an open frame.
Disadvantages of Corrugated Metal Roofing
- Movement can loosen panel fasteners and, on occasion, produce annoying noises. The noises are rare occurrences and routine maintenance can help solve both problems.
- A more worrisome problem is rapid corrosion brought on by the use of incompatible materials, specifically dissimilar metals. A knowledgeable installer should be able to foresee and avoid any problems in this area.
- Cost can be considered a disadvantage, but only if the short term is considered. In the long term, a metal corrugated roof is not anymore expensive. It lasts longer, and due to its fire, hail and wind resistance, reduces insurance premiums.
- Finally, thanks to the rising cost of oil needed to make asphalt shingles, the difference in price between corrugated metal and asphalt shingles is shrinking.