I was asked the following question:
I am looking at samples of several roofing products. Two of them claim to be 26 gauge, but they feel very different. One is clearly lighter than the other. Can I use a micrometer to test the thickness and figure out which one really is 26 gauge? Is there a chart that would tell me the appropriate thickness for the 29, 26 and 24 gauge of roofing materials? Please review and advise. This is very important to me.
My response:
As long as you gauge a flat area of metal, sure you can check it with micrometers.
I have long been a proponent of the industry looking at steel roofing in terms of decimal thickness rather than gauge.
Too many games can be played with gauge in regards to tolerances, with paint, without paint, etc.
You can find charts referencing gauge and decimal thickness but as you will see there is a wide range of tolerance on decimal thickness for each gauge.
What is “oil canning” ? I was asked to sign a waiver if I installed a 24 ga smooth flat standing seam roof. Thanks
Comment by Andre Leamy — February 5, 2010 @ 10:26 am
Great question Andre. Thank you.
Oilcanning refers to ripples which can appear in the surface of the panels. Most common causes are inherent and unavoidable stresses in the shape of the metal, and imperfections in the flatness of the surface being installed on. Other causes can be improper panel formation and improper installation.
Requiring this disclaimer is not uncommon.
You may wish to ask the contractor if they have any options for ribs or striations in the panel which can help to mask the appearance of oilcanning.
Comment by toddmiller — February 5, 2010 @ 10:42 am