Galvanized vs Galvalume — Whats the Best Metal for Siding & Roofing

You have finally convinced your wife that you need more storage space. Youve decided you want to check out available garage packages so you can get the most out of your money. There are numerous options, styles, and prices out there right now. First, you have to decide on what size you want constructed? Do you want sliding doors or overhead doors? Should you install windows? What type of entry door would work best for your application? These options are functional and aesthetically reasonable considerations, but one long-term option may weigh more important than any of those listed above.

You have two options when it comes to the type of metal siding and roofing to select from for your pole barn materials. Most people are familiar with galvanized metal. Yet, another less known selection is galvalume metal. Galvanized metal is simply a sheet of steel that has been coated with a thin layer of zinc oxide. The zinc is applied to protect the steel from the elements that can lead to corrosion and rust. This corrosion and rust will eventually weaken the metal and finally to a complete breakdown of the steel. At this point you are left with nothing but a broken down and unattractive structure. Galvanized metal will begin to breakdown within 10 to 15 years of element exposure.

You may ask why this corrosion or breakdown of zinc occurs. It is important to understand that this corrosion isnt immediate with galvanized metal. Initially, galvanized metal maintains its appearance even better than galvalume metal, but dont be fooled. This initial appearance will begin to deteriorate and when it does, it does so fairly quickly. The zinc coating begins to corrode at the cut edge and after time it simply corrodes completely off the entire surface of the steel. This snowball effect continues across the entire span of the metal, just not in a spot here or there.

On the other end of the spectrum, you have the option of selecting a galvalume metal for your siding and roofing material. Galvalume metal starts out basically with the same standard steel, but the coating that is applied to this surface is different by not only using a zinc coating, but an aluminum and silicon coating as well. These three ingredients are mixed and then applied to the steel sheet using a hot-dip method.

Galvalume is an excellent product for long-life roofing and siding material. The aluminum additive, along with the zinc, allows small particle areas to form within this coating. Any corrosion that occurs does so within these open particle areas. So, you may ask how they differ since both galvanized and galvalume both experience some type of corrosion? Galvanized metal corrodes in a linear fashion and eventually depletes the zinc coating entirely. Galvalume, on the other hand experiences some corrosion, but on a smaller and less significant scale. Galvalume will not breakdown completely, as galvanized will. This is why galvalume metal manufacturers are able to offer such a significant longer warranty period. Some manufacturers offer warranties up to 25 years.

So, when deciding what garage kit to choose, please consider your choice of metal siding and roofing carefully. Its easy to forget this important option when making other important decisions like color, layout, style, windows, and doors. All of those will be for not, if the right option is not chosen wisely.

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