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TOPIC: Maintenance

oil canning

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I have not seen too much discussion on this and this is my greatest concern. We are in the middle of a new metal roof installation, beginning on the new addition and heading to the existing house (replacing old asphalt shingles). By the end of this first day, we see dents, ripples or "oil canning" (not certain about the best term) which is enough to have called the GC to STOP the installation until we understand more about what is happening. I have read about the nailing or fasterners too tight, the thickness (we are not certain we have 24 guage) and that the heat (it is in the 90's here in texas) . . .could be problems. We are installing an 18" wide panel, standing seam, no exposed fasteners. The panels were run out on site with a machine that is 10 years old but "works like a charm" according to the fabricator. It is the standard "Sierra Tan" by Kynar (or at least that is my assumption). What questions should I be asking my roofer????? Your help is appreciated.
Guest User

8/6/2004
In most cases, oilcanning is not cause for rejection of panels or installation because, to some degree, it can be inherent and unavoidable. Therefore, I commend you for bringing this question up now rather than after the roof is entirely installed. First of all, have you measured thickness of the metal? There is an industry tolerance for 24 gauge but, still, you ought to verify you're getting pretty much what you contracted to get. Can you find out who the metal supplier is? Can you see any ripples in the metal before it is formed? Can you see them in the panels before they are placed on the roof? This would help in indicating the problem is due to inherent stresses in the metal. Tight clips and/or fasteners can cause a problem. Improperly formed panels, including the locks, can also be a problem. Doe the ripples seem to correspond to clip placement? Are the ripples worse when the panels get heated by the sun? These things can help indicate too tight of clips or fasteners. Installation over an uneven roof deck can also be a problem. Ask the fabricator if he can run strengthening ribs in the flats of the panels -- that can help. Another possibility is backer rod -- thin plastic rods which are installed underneath the center of the panels. They put a little upward arc in the panels and can help remove ripples. Send me pictures if you wish. [email protected]
Guest User

8/6/2004
WHAT IS THE REAL THICKNESS OF A 26 GUAGE ROOF AND HOW DO I DETERMINE I AM GETTING A 26 GUAGE METAL ROOF
Guest User

1/17/2007
There are industry tolerances and range on metal thicknesses. Painted 26 gauge should be approximately .018 - .020" thick I would think. If you're using an MRA member manufacturer, they should be able to help you with figuring out the thickness of their panels.
Todd Miller
Isaiah Industries, Inc.

1/17/2007
Todd, I am having the exact same concerns. I voiced my concern early in the process, but was told "oil canning is expected......". How can I determine if the denting on my roof is due to the inherent properies of the metal or due to the other instillation related things you mentioned? Is there a level of "oil canning" that would warrant rejection? I have attached photos. Thanks in advance for any advice.
Guest User

5/19/2007
My photos did not post. I hope you don't mind but I have sent you a couple of photos to the email address you gave to Todd. Thanks again.
Guest User

5/19/2007
Sure.
Todd Miller
Isaiah Industries, Inc.

5/20/2007