End grain of wooden components is where water most easily enters wood and causes rot. Think of a piece of wood as a bundle of straws where the end consists of thousands of little tunnels ready to soak up water. To prevent this the end grain can either be hidden or concealed in such a way that water can't get to it ... or it can be coated with urethane to "clog" the ends of the "tunnels" (end grain) to prevent water penetration.
Vixen Hill Shutters use a conceal method called "Blind Pocket Mortise with Capping". This method didn't exist one hundred years ago because the tooling needed was beyond most carpenters. The aforementioned method involves cutting a rectangular slot in the vertical "styles" of the shutters then plugging a shouldered tenon into the pocket. The tenon end grain is then hidden in the pocket while the top edge of the shutter gets copper or aluminum capping to protect the end grain of the styles.
The End Game for a well built mortise with capping shutter occurs in extreme situations of near zero sun light and locations of high humidity - like under plant arbors or behind trees and bushes.
Vixen Hill has created shutters made to last because of their design. Four decades of shutter manufacture have resulted in some of the finest shutters available in the word.