What kind of flashing should be provided under trim at interior and exterior building corners?
I have been investigating details for flashing at exterior and interior corners for wood frame residential buildings with vinyl siding and pvc trim boards. I found an article, “Details that Keep Walls Watertight” which recommends a double layer of house wrap at the corners. CertainTeed’s vinyl installation manual recommends a 20 inch wide aluminum coil be run up the full length of the corners, for both vinyl and pvc trim. Do you think that is necessary or desirable? Thanks for your help!