(Original one is here: https://www.houzz.com/discussions/6425598/porch-post-bottom-rotten-how-to-fix-it-please#28907820)

I opened up all four post base trims, now I realized how the bottom went rotten and how they were installed originally. There was, I guess, a 3～4 inch long rebar (3/4 inch diameter) built from concrete foundation, then the post sit and glue on it when the roof were not yet built, later the tiles were lay out on the foundation, and tiles were cut around the post base, finally 6-inch height trims were installed.

The problem is: a “pit” was formed around the post bottom due to the gaps between tile and post, it is nearly half inch deep, and some these gaps were pretty large, > 1 inch width, the builder did not do a good job here. Overtime, water got in, then trap, then wood rotten.

Therefore, replacing the whole post will need to remove the rebar, and use other solution to fasten new post on the foundation, however, because of existing tiles, there is not much surface area to work; also what is important is to address the “gaps” between the post and tiles, otherwise, water would be trapped again.

I am thinking following steps to fix them.

1, clean up the rotten wood, it will open up the space, then flush the underneath area with high strengthen mortar;

2, further strengthen the post wood that still well attached to the rebar with Abatron;

3, use two half-square TP wood snuggly squeezed into the gap between flushed base and post, also glue around the rebar;

4, apply Abatron again to fill any niches between post and TP wood;

5, Screw bracket between TP wood and post; finally attach 6 inch trim to cover it, and paint.

Please, any comments and suggestions are well welcome on this plan. I am now building two 9 feet long temporary post to support the roof. Thank you !

one still good standing post, but already began to rotten

The worst rotten one

The rebar under the post