Mike Lamb Posted January 8, 2012 Report Share Posted January 8, 2012 When installing an open valley, use 16 oz. copper flashing at a minimum (or its equivalent) over WinterGuard? Waterproofing Shingle Underlayment (or its equivalent). Preformed ?W? style valleys are preferred (Figures 16-11 and 16-12). The aluminum used on this valley looks like typical .0145 coil stock. What is the equivalent AL to 16 oz. CU? This is a Certainteed Grand Manor Shangle roof. There are so many problems on this job that the valley issues are just piling on. I am very aware of the underlayment issues. The builder is not going to be happy with what his roofers did and did not do. Click to Enlarge 29.23 KB Quote Link to comment Share on other sites More sharing options...
Marc Posted January 8, 2012 Report Share Posted January 8, 2012 It's an error in choice of unit of measure. Where'd you see this? Marc Quote Link to comment Share on other sites More sharing options...
Mike Lamb Posted January 8, 2012 Author Report Share Posted January 8, 2012 It's from the Grand Manor installation instructions. http://www.certainteed.com/resources/Gr ... nstall.pdf Quote Link to comment Share on other sites More sharing options...
Marc Posted January 8, 2012 Report Share Posted January 8, 2012 The writer probably meant 16 gauge, which is 50/1000 of an inch when the material is copper. A primer on copper sheet metal gauge Marc Quote Link to comment Share on other sites More sharing options...
Bill Kibbel Posted January 8, 2012 Report Share Posted January 8, 2012 Ounces is the proper measurement for copper sheet. I think that it means 16 oz. copper = one square foot weighs 16 ounces. This translates to .0216" or 23 gauge. Quote Link to comment Share on other sites More sharing options...
Tom Raymond Posted January 9, 2012 Report Share Posted January 9, 2012 Wow. When they cheap out on an application of that price point here they use steel flashings and drip edges. That's a shame. Quote Link to comment Share on other sites More sharing options...
kevinbrown10 Posted January 10, 2012 Report Share Posted January 10, 2012 I agree with Bill that ounce is the proper unit of measuring the thickness of copper sheets and it can be easily converted to gauge the more popular unit. Quote Link to comment Share on other sites More sharing options...
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