How to repair or replace rotting deck posts?

9 years ago

A lot of people say that the posts can not contact the concrete, unfortunately it appears to be the case for my deck. We just purchased the house a few weeks ago and found the bottom of the post a bit rot. As you can see in the pictures the bottom part of the posts are buried in concrete. I tried to touch the bottom of the post with my fingers and it feels a bit hollow. How do I resolve this issue? Do I need to remove the posts, fill the hole with more concrete, put a concrete pier and metal bracket, then get a few new posts? How much would it cost? I just want to get it done right this time so I don't need to worry about it in the next 15 years

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User

9 years ago

Seems to me the best looking repair would be to install temporary supports, remove the old posts, clean out the holes and fill them with hydraulic cement. Reason? Hydraulic cement does not shrink as it cures and it should be possible to finish the surface level with the existing surface.

Then use a plate about 6" by 6" over the patch to mount the new standoffs. That spreads the weight and takes the weight off the old hole. The finished base can be trimmed to hide/complement the plate and stand off base.

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Comments (7)

User
9 years ago
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.
Lauren De Buyer thanked User
User
9 years ago
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.
Lauren De Buyer thanked User
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Lauren De Buyer
Original Author
9 years ago
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.
Lauren De Buyer
Original Author
9 years ago
last modified: 9 years ago
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.
Lauren De Buyer
Original Author
8 years ago
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.
User
8 years ago
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

the post base.