Historically I have heard of applying white lead to joints as a preservative in shipbuilding, but I have never seen evidence of any type of coating in building joints.
I agree that their may be some woods that end-sealing helps minimize cracking such as the tropical hardwood cambara mahogany, but generally is not needed.
Perhaps applying anchorseal to the joints of an outdoor frame such as a pergola would increase durability?
Good luck with your project;
Jim
