Can I repair these deck support posts, or do I need to replace them?

Question

Two of the (6"x6") posts supporting my deck are damaged by rot. Can I repair these posts, or must they be replaced?

(the jack stand in the picture is my own doing, out of paranoia).

Answer 1

Those posts definitely need replacement. There is too much structure above to risk damage or bodily injury should one of these posts start to collapse downward due to the rot at the base.

From looking at your photos it does not look like too complicated of a job to replace them. The starting plan would be to work on one post at a time and provide a temporary post or shoring next to the area of the post being worked on. The biggest complication I can see will be the fact that one or more of the posts are embedded in the lower patio concrete slab. In addition these posts most certainly enter the ground down to some type of support foundation so you will have to open that up so a new post will rest on this same foundation.

Answer 2

"A" doesn't look that bad. If it isn't wiggling I would just wrap it in a post sleeve - just google the term and you will find a variety that would work. If it is just that breach at the bottom it won't effect the support and wrapping it in a sleeve could make it last 20+ more years given there isn't water sitting on it. Note that I am not there and just looking at the picture.

Another option for "A" would to be bolting a post collar on the concrete and "sister" another post right next to it or close.

"B" is just a replace. It is much easier and the footing needs to be dug out and you need to get another footing (3' but depends on zone) and add new post.

Before adding new post please do you best to waterproof the base. The posts will last another 10-20 years if installed right.

Just a side note here: no way in the world you should have a swing on a joist. The slight turning of the joist could be causing the posts to torque slightly. Honestly the damage at the bottom of each post with splinters looks like the posts were torquing (not blaming the swing). A swing with a 30 pound kid isn't hurting anything but if an adult sits on it and moves at all - your joists weren't meant to deflect horizontal pressure.

To clarify I am suggesting something like this sleeve not a post wrap. Simpson also makes a post sleeve that is the industry standard but they are probably pretty pricey.