Can I reinforce a pergola at the base of each upright without risking?

Ann Cassler
by Ann Cassler
I have a pergola made of pressure treated lumber, 4x4's holding up a total of 14 2x6's and some corner bracing. It's attached to the patio by metal "cups" that are bolted into the concrete. It has been in place for 4 or 5 years. I'm considering some reinforcement in the form of untreated, painted 1 x4's and 1x6's going from the base to 3 or 4' up and topped with molding as I've seen on Hometalk awhile back. They said they added it as a design element but I would consider it only for the purpose of reinforcement.

Question: can this addition invite trouble by allowing moisture to get into the covered 4x4's and be trapped against them thereby causing rot even though the boards are pressure treated? Would caulking prevent this or drain holes? Also I'm anticipating some small gaps because of the metal "cups" at the base.