We are putting a second story on my son’s house.  Will be installing a metal roofing product so we went to the supplier and got recommendations for underlayment (I have always been a fan of WR Grace but their products are getting pricey) and the supplier suggested a product that was a fairly new line, Owens-Corning Weatherlock Metal.  This product is specifically made to go under metal roofing.  We took delivery of 32 sq and started to install it today and shortly thereafter the building inspector stopped by,  everyting was fine until I got to the end roll laps.  The instructions said to use a asphaltic based primer to  meeting ASTM D41 standards to seal the ends.  Called the supplier and was told that his rep had not been able recommend a “brand” of product and had no idea wat to use.  I thought this was insane, called OC and guess what?  After more than 45 minutes on my cell, and talking with 4 different people, OC was not able to tell me what to use (other than it had to meet ASTM D421 standards) HOW DUMB IS THAT?  Wasted all afternoon, had the architets office, and the supplier, and myself on the internt looking for a lap sealer for 4 hours.  Finally the supplier located a product that is stamped ASTM D41.  Yes, I could have used andythng I guess (OC said just to nail it with button caps) but the inspector was there reading the instructions with me and he wants to see the lap saealing product.  Yes, I am in th e130mph hurricane zone.  How poor is OC’s technical support.  Next time I will bite the bullet and use WR Grace Ultra.