I have a deck which the 8"x8" supports are concreted in the ground and run through first floor patio, through the second story and act as supports for the upper deck railing. The second floor railing needs to be replaced and the 8x8 has rotted at the level of the second story floor. Can I safely splice into the existing post? Or should I be looking at replacing the whole support? This is est. 24ft. tall. thx