I can not find anything in the code that allows for a deck post height above 14 feet. Both 6x6 and 8x8 pressured treat max out at 14 feet. what should be used if the deck height is 15 feet? (house has a 12 foot basement with a sloped rear yard)
Engineered steel posts and frame.
14 ft concrete pier!
Angled post bracing can reduce the height of the posts but an SE would assess that.
Angle post (Knee Bracing) can reduce the effective height, but the braces have to be in the X and Y direction and properly attached to the post and deck.
Client’s lawyer: “Hey you did an inspection for my client last year, and he has a code violation that is going to be very expensive for him, and you missed it.”
Inspector: “We do home inspections, not code inspections.”
Client’s lawyer: “That’s not what you said when you told him his deck posts didn’t meet code.”
IRC R507.1 and R301.1.3 are the answer to your question.