Here's another in our Q&A series. Have a question? Post away!
Q. What's the difference between aluminum roofing and steel roofing? Which is better? Why?
A. Ah, the old steel vs. aluminum conundrum. In general, we find that folks not familiar with the technicalities of metal roofing often use the words "aluminum roofing," "tin roof" or "metal roof" interchangeably. The fact is that there are a number of metals commonly used for making roofing materials and they each have different characteristics.
Aluminum roofing is among the premium choices for metal roofing material, just like its more expensive cousins, copper and zinc. That's partly because it offers superior corrosion resistance to regular ferrous (steel) roofing options. This characteristic makes it a frequent choice in coastal applications. A few things to know about aluminum:
1. As a bare, natural metal, aluminum is not very pretty as it ages, so it's most commonly employed as a metal when it's finished with a painted surface.
2. The usual alloys of aluminum used for roofing applications tend be very formable and easy to work on site, making it a very easy material for most installers to use on a roof.
3. Aluminum is also usually the lightest metal used for roofing. Its strength-to-weight ratio is among the highest of the "common" metals (that's why most of the airliners in the sky use aluminum for their air frame), and so a thinner piece of aluminum can often do the job of a thicker piece of other metals. This lightness and thinness also means aluminum roofing stores the least amount of heat (think of the aluminum foil used for baking), and so becomes cool quickly once it stops receiving direct sunlight.
4. Price-wise, aluminum is in between most of the finished steels and copper and zinc.
Steel is the most common material used with roofing metal. The term usually refers usually to one of the zinc-coated steels (Galvanized, Galvalume, Zincalume, etc.), and here's a rundown on its attributes:
1. Steel roofs are usually supplied with a colored finish.
2. Modern steel roofs are lightweight with very good corrosion resistance.
3. Steel roofs are appropriate for the vast majority of roofing applications where value is important.
Bonus round! Some people hear "metal roofing" and immediately think "tin." But actually, tin roofs are very rare now. For a while, tin was plated onto steel for use as a construction material because tin is very corrosion resistant (and thus used for tin cans), and this created a metal that was strong, thin, and corrosion resistant. Its heyday as a roofing material existed for maybe 50 years around the turn of the 20th century. It's since been replaced with version of "Galvanized" steel roofing where, instead of tin plated onto steel, alloys of zinc are plated onto steel to provide corrosion resistance. The resulting metal has become the most popular type of metal for construction materials and is superior in almost every way to the old tin roofs - and at a better price.