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TOPIC: General Discussion

"Oil-Canning"

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We are building a new custom home and we selected a standing-seam metal roof material manufactured by Drexel Metals. After about half the roof was installed we noticed that most panels have a wavy appearance when viewed from ground level. The contractor said in a letter to us that "this phenomenon is clearly visible on most metal roofs, given proper lighting and viewing angle" and said that his distributor feels that "the oil-canning is completely within the normal tolerances of this product and well within industry standards." Needless to say, I am surprised to hear from the contractor that this appearance is "normal," and I remain disappointed with the appearance of the product -- especially because this not a cheap house (about $400/SF). Is our contractor correct that a wavy appearance is normal? Did we just select an inferior product? Are there metal roofs that appear smooth and flat regardless of "lighting and viewing angle?" Should we accept the contractor's explanation and the uneven appearance, or should we ask him to do something to improve the appearance of the roof? Thanks very much for your input.
Guest User

6/7/2005
The Metal Construction Association has a Technical Bulletin on this subject which can be seen at: http://www.metalconstruction.org/pubs/pdf/95-1060%20MCAoilcanning.pdf There are a number of things which can contribute to a waviness appearance of the installed roof. They include inherent properties of the metal itself, forming problems, product design, uneven roof deck, rough handling of the panels, inappropriate clips, and improper fastening. Sometimes, all of these things work together to cause the end result. Sometimes, the wavy appearance may diminish with time. There are a couple of things which could cause that to happen. I really cannot begin to answer, especially "long distance" what might be going on with your roof. In some cases, a "backer rod" can be installed behind the panels to put a "crown" in the base of the pan and remove some of the waviness. There are very few standing seam roofs which will not show some waviness, particularly under certain conditions. My suggestion would be to contact the folks at Drexel and give them an opportunity to provide input as to what is happening with your roof. I hope this helps. [email protected] Todd Miller
Todd Miller
Isaiah Industries, Inc.

6/7/2005
Thanks -- I've contacted Drexel and I'll post their reply if I hear back from them.
Guest User

6/8/2005
I have let Drexel know they would probably be hearing from you. Todd Miller
Todd Miller
Isaiah Industries, Inc.

6/8/2005
Well, a representative from Drexel took a look at the roof and says that the degree of oil-canning is "normal." If this really is the case, then I an VERY disappointed with the aesthetics of this product and would certainly not use it again. I've attached a photo that shows an illustrative section of the roof. If you have not had a metal roof before and are conderned about aesthetics, consider yourself forewarned that this particular product (26 gauge) will NOT produce a smooth, uniform look. This may not be a big deal to some, but where the roof is highly visible (for example, our house is a ranch with low roofline) this may not be acceptable to you. It certainly isn't to me.
Guest User

7/8/2005
Oops! Sorry, I attached the wrong photo to the last post. View the attachment here to see the oil-canning.
Guest User

7/8/2005
I understand your concern. The panel on the right has been made worse than it would have to be, because of the gable end treatment they used. There are other treatments which would have been better. The ripples I see are not terribly uncommon but again I understand and appreciate your concern. I am sorry that there is not a lot that I can do. Todd Miller
Todd Miller
Isaiah Industries, Inc.

7/8/2005