Ripped up old concrete patio (part of it was screened and didn’t get wet but part of it is outdoors) and found that the rim joists were about half below grade. 

Will be replacing any rooted wood and want to seal and flash before installing new patio stone. Looking at the grade and adjoining driveway and rest of back yard there is no way that I can regrade the patio to be lower than the rim joist. 

What would be the correct way to waterproof the rim-joists? 

Home was built in the 1960’s – located in New Jersey.