I agree with Daniel on the rtd, as anytime I found it mentioned was to plywood manufacturing. Though all my research has shown APA uses the same glue in Exterior and Exposure 1 grades, only the bond durability has changed from the application. Also, 1/2" CDX is not warranted by the manufacturer for underlayment for tile, only as roof or wall sheathing, because of the knot holes and other voids. But now I'm nit-picking. Be safe, G
I bought some of thaRTD at HD and "Ready to Delaminate" seems most accurate. Several 4 X 4 pieces I had stored in a covered protected outdoor area warped badly and started to delaminate after a rain. They did not get wet, only exposed to high humidity. Some scraps I left out in the actual rain completly came apart !! I am not impressed with this stuff. Guess thats why its cheap at 13+ $ a sheet.