I have a cabin in the mountains. Most of the small buildings are built on 6x6 posts up to 16 feet off the ground. Other half is on a block foundation. My question is. I want to extend the deck out 10 feet. To keep in line with the original I must use 16 foot 6x6 posts. I am extending out 10 feet x 26 feet long. To do this I must bring up piers to support the posts.Are piers stable and strong enough for this? What would be the calculation to decide how much footer and how thick the pier. I must bring up the pier about 2 feet to keep within the 16 foot long posts.

Thanks