Corten Roofing Vs. Bare Cold Rolled Roofing

Bare Cold rolled steel is used as a less expensive option to A606 Type 4 ( Commonly referred to as Corten ).
Bare Cold Rolled is widely manufactured for a variety of different purposes including metal roofing and costs less.
Both of these panels are completely different. However, they look similar in appearance.
After installation and exposure to normal weather the surface of the panel develops a gorgeous rustic finish and texture. CorTen contains copper, chromium, manganese, and nickel which makes this material more expensive. Cor-ten resists the corrosive effects of rain, snow, ice, fog, and other meteorological conditions by forming a coating of dark brown oxidation over the metal, which inhibits deeper penetration and negates the need for painting and costly rust-prevention maintenance over the years. Corten will last longer and would be more desirable in harsh climates. Harsh climates include environments with exposure to salt and climates where the material will be wet often. If you do not have a harsh climate Bare Cold Rolled is a less expensive option.


What does it cost to deliver the rustic roofing ?

It can be shipped anywhere in the country very inexpensively on one of our route trucks. The price depends on the job location, length and weight of panels.  Just request a quote and we will quote the delivery price.


How long will this roofing last ?

There is no definitive answer to this question. It depends on the environment and the way in which it was installed. Many projects using bare cold rolled and corten products were installed in excess of forty years ago and there are no problems. It is likely that the panel will last at least two to three times as long as wood shingles. Corten will have approximately double the lifespan of bare cold rolled steel. A lifespan of sixty (60 ) to eighty ( 80 ) years could be possible for A606 steel. One of the most common problems is using a light gauge steel in a 24GA to 29GA range. Using a heavier gauge steel is the most important thing you can do to make your roof last a lifetime. There is no warranty for either bare cold rolled or Corten, but there are a number of things that you can do to increase life span of the product. See next FAQ


What can be done to increase the lifespan of Corten or Bare Cold Rolled Roofing ?

Use a heavy gauge steel in a 20GA or 22GA.
Keep the roof free of debris and falling objects.
Have a minimum slope of 3 in 12.
Prevent moisture entrapment. It is not a rustproof material. If water is allowed to accumulate in pockets, those areas will experience higher corrosion rates, so provision for drainage must be made.


What gauge steel should I use ?

Metal roofs in a galvanized, galvalume, or painted finish are normally 24GA to 29GA.
However, with Bare Cold Rolled or Corten products never use a gauge lighter than 22 GA.
The thicker gauge makes it more difficult for the material to rust through.

Will the panel continue to rust ?
A606 ( AKA Corten )

Corten never completely stops rusting. The weathering process occurs after the panel is installed.  It eventually decreases and from that point on the finish acts as a protective coating for the base metal.
This protective coating essentially stops the corrosion.  Laboratory analysis of the rust film have shown that the alloying elements in the steel, particularly copper, chromium, and nickel produced insoluble compounds that clogged the pores at the rust/steel interface, thereby ending the regeneration.

Bare Cold Rolled Steel

This panel will continue to rust.




Will the rust stain the surrounding areas ?

Yes, rust runoff will likely stain the surrounding areas.


Is there a warranty ?

There are no warranties for products made from Bare Cold Rolled or A606 Steel.
In addition upon placement of order it is required that you initial a brief statement that refers to " No Warranty "
Click for a copy of the document that will need to be initialed.


What do I have to do to get the roofing to rust ?

Nothing. This material will rust on its own if left exposed to the weather. Getting the material wet will increase the speed in which it rust.


Does it come pre-rusted ?

Currently it does not, but for a premium price it could be done. Unless you have money to waste let nature do the work.


What about color matching the screws ?

Screws are furnished in a Koko Brown or Terra Cotta Finish.


Is trim and flashing available.

Yes, trim and flashing is available in a 22 Gauge in either bare cold rolled or A606 type 4 ( commonly referred to as CorTen ). Also 48" X 120" flat stock is available.
There are standard details and sketches on this page. If what you need is not listed just draw a sketch and E-mail or fax it and it probably can be made.


What is Corten ?

COR-TEN® steel is becoming more popular by roll formed product end-users. Its unique look and naturally oxidizing finish make it especially desirable for many architectural projects. Weathering steel, best-known under the trademark COR-TEN steel, is a group of steel alloys which were developed to obviate the need for painting, and form a stable rust-like appearance if exposed to the weather for several years. Cor-ten resists the corrosive effects of rain, snow, ice, fog, and other meteorological conditions by forming a coating of dark brown oxidation over the metal, which inhibits deeper penetration and negates the need for painting and costly rust-prevention maintenance over the years. COR-TEN® is a trademarked name owned by U.S. Steel.


Can I buy Corten ?

No, Corten is not available. What is available is steel in an A606 finish. If somebody tells you that they are supplying you Cor-Ten they are almost certainly lying or don't understand their own product.  Simply ask them if their steel coil was purchased from U.S. Steel.  If the answer is " No " or " I don't know " than they do not know what they are talking about and you should use caution when dealing with them. When someone needs COR-TEN® on the West Coast they are normally referring to A606 Type 4. If you want COR-TEN® this will be the best available option. Weathering steels, such as ASTM A588, A242, A606 and COR-TEN® exhibit superior corrosion resistance over regular carbon steel as a result of the development of a protective oxide film on the metals surface which slows down further corrosion. A606 steel is available in metal roofing/siding panels, standing seam panels, flat stock, and coil form. If you are looking for a panel that will give you a rustic look the two best options are bare cold rolled finish and A606. A606 will cost more, but it will last longer.


What is A606 Type 4?

The original Cor-Ten received the standard designation A 242 ("Cor-Ten A") from the ASTM International standards group. Newer ASTM grades are A 588 ("Cor-Ten B") and A 606 for thin sheet. All alloys are in common production and use.

It is also recommended that you read the recommendations and cautions which can be accessed by clicking on a profile from the home page.

Is square footage charged by the coverage of the panel or the actual width of the panel ?

7/8" Corrugated
The width of the panel is 37".  On a roof there is 32" of coverage and on a wall there is 34 2/3" of coverage. Square footage is based upon 36". 

1/2" Corrugated
The width of the panel is 26".  There is 24" of coverage. Square footage is based upon 24".

R Panel & B Deck
The coverage is 36". Square footage is based upon 36"