Corrugated Metals Blog

Maintaining Corrugated Metal Roofs: Preventing White Rust

Posted by Ken Carlton

Jun 25, 2013 9:00:00 AM

 White RustCorrugated roofing and siding is popular with homeowners and businesses alike, thanks to beneficial attributes such as long life, easy installation, and low maintenance requirements. Most corrugated products are made from galvanized steel. Galvanization is the process of applying a thin layer of zinc on the surface of the metal to protect it from rust (oxidization) and corrosion. 

Galvanized steel products are designed to last for many years in roofing and siding applications. However, it is very important to know that packaged bundles of corrugated products must be stored indoors, in a dry environment. Improper storage of stacked sheets (i.e. outdoors, or in environments where moisture can form between sheets) exposes galvanized steel to white zinc corrosion, or “white rust.” White rust is the result of electrolytic action which takes place between the steel sheets when water exists without oxygen.   

White rust’s corrosion usually appears as a white deposit on one or more areas of the galvanized metal. If seen wet, it will feel waxy in texture, when dried it can feel brittle and hard. If this is spotted early enough, it can be treated and prevented. The good thing is that the corrosion of the zinc is only on the surface level and hasn’t penetrated to the metal. However, if left unattended, the zinc will be further eroded and will leave the metal unprotected and vulnerable to oxidization. Of course, it can be unsightly as well, so tackling the issue when it first is noticed is important.

Here are a few tips that can help prevent white rust and what you can do if it develops on your roof, siding or other places that utilize corrugated metal:

  1. Most importantly, be certain that the materials are stored in a way that will provide enough air to allow the zinc coating to dry and protect. Also, be certain that in the storage area that the zinc coating doesn’t come into contact with the various elements that could begin the corrosion process for the zinc. This is the most critical part of maintaining rust free corrugated metal. Too many suppliers and wholesalers fail to properly store the corrugated metal.

  2. Remove any item that may be causing destructive corrosion in areas already damaged. This could be strapping or other items used in storage. If the white rust has begun while the product is on the building, make sure that it isn’t in contact with things like copper pipes or lead, etc.

  3. Pour white vinegar over any areas that display white rust. Allow the vinegar to sit for five minutes, then rinse and wash the area with warm water. For light rusted areas, this should remove the stain. If so, apply a coat of zinc-rich water or perhaps a solvent-based rust resistant primer.

  4. If the vinegar doesn’t remove the white rust, scrub off the rest of the stain with sandpaper until the white coating of the rust has been removed. Do this for all areas of the surface that may be exhibiting white rust.

  5. Rinse the sanded area with warm water, dry with a clean cloth rag.

  6. Apply a layer of zinc-rich primer to the sanded areas. Wait until dry, brush on a coat of galvanized iron primer. Paint the entire roof or siding. Let dry.

  7. You may then finish the process by painting on a layer of exterior paint for metal.  

     

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Topics: corrugated metals, roofing and siding, corrugated, metal roofing and siding

Introducing our R-Panel Product Line

Posted by Ken Carlton

May 3, 2013 9:00:00 PM

Corrugated Metals would like to introduce the newest member of our product family: the R-Panel. This product line is a new profile for Corrugated Metals, but is already very popular for roofing and siding applications.

What are some of the specifics? It’s corrugated sheet metal that provides a maximum coverage space of 36 inches. With a variety of peaks and valleys, this product line is a new variation of the panels we already offer. Although the R-Panel comes in a standard shape, our engineers can provide custom lengths, depending on your specific application and needs.

On our quest to be more of a one-stop shop in the metal roofing and siding industry, the R-Panel product line is only the first of many new products we plan on rolling out in the next few months. Made specifically for commercial and light industrial applications, this is the next big thing in roll formed roofing and siding projects—come meet the new R-Panel!

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Topics: corrugated sheet metal panels, metal roofing and siding, panels for roofing and siding applications