Can you show some pictures of the entire deck and railing construction so we can see what it's holding up and how strong it needs to be and how hard it might be to replace.

Are the posts embedded in concrete poured around the posts in larger holes? As you can see, there are large gaps between the post and the concrete---which have caused the rot by allowing standing water in the gaps.

To replace the posts, you will need to build temporary supports too allow post removal.

Best option would be to pour new concrete piers, replace the rotted posts with new ones affixed to the piers with post standoff brackets. Those brackets are bolted to the concrete(usually a center bolt in an anchor) and the post sits in the top about an inch or so above the concrete, with screws holding the post in the bracket.

A second option would be to remove the rotted posts, fill the holes with concrete and install a metal plate over the concrete---since the filled holes will not be strong enough to support a new post and the load. Then use the post standoff brackets to install new posts.

A third option would be to dig/pour new piers at different locations under the deck and install new posts in those locations, again using the standoff brackets.

Thanks lazy_gardens, here are two pictures which have a better full view of the deck. It appears to me that there are 3 posts that need to be repaired or replaced.

Thanks HandyMac. You are right about how the posts are embedded in the concrete. If I go the first route. Do i need to enlarge the holes and then pour concrete piers in the holes? The current holes are not very deep. Less than 1 foot, more likely only 8 inches deep.

Hi, HandyMac. do you have a picture or something that shows your design? I am thinking of going that route but just want to be sure to get it done right. Thanks.

This is the type base. It holds the bottom of a square post off the ground so there is no wood to concrete contact. It needs to be installed with concrete screws/anchors---that is why I recommended filling the holes.

Then use cedar wood trim(3/4" to 1" thick and 6" wide to frame and hide