I'm in Florida and am presently using commercial grade white pine dado joint supers. The ends of the boards have rough cut open grains. I've sealed the ends with caulking and double or triple coated the ends with exterior enamel paint. Whatever I do, the ends start rotting out, often within a year.
Does anyone know a Florida one SE source for cypress supers?
Alternatively, does anyone know how to postpone or stop this rotting? Is obviously coming in from the dado joints or more likely the end cuts of the boards?