Sorry about the delay in getting back with everyone. With a death in the family I was out of town for the past few days. Now, answers and comments... Matt, Hopefully only a few days at most. Mike, at times I'm adventurous but this is really not one of them. Through the years I've delt with "dreaded" failing lp siding problem and FPE Stab-Lok electrical panel (including a dead short in a lighting fixture that did not trip the breaker), so I'd really like something that we know works. Marc, That was one of the first things I sent him but unless I'm missing something it only says that it must be installed over a "Water-resistive barrier". While they imply that you should use HardieWrap® weather barrier, it does not seem to require it. So, If I am reading the responses correctly, while it is not everyone's first choice, 30# felt is acceptable to everyone with 1/2 lapped 15# a second choice. Jim, I specifically asked that "All wall penetrations will be flashed utilizing self-adhering, self-sealing, butyl material". Is this good enough or should I specify Vycor?