I need to repair two deck posts that have rotten out on the bottom. The posts originally sat on concrete piers. Unfortunately the tops of concrete piers are about 6″ below grade, making the original pressure treated posts sit 6″ into the soil. Changing the grade is not an option. A third post was repaired by cutting out the bottom rotten section and splicing in a new 4×4 piece on the bottom. As before, the new piece sits 6″ below grade, waiting to rot again.
My first though for a repair was to drill and epoxy in a couple of bolts into the top of concrete piers. Then using a piece of sonotube and concrete on top of piers, raise the pier out of the grade to just under the bottom of the cut off post. I then planned on embedding an adjustable post connector to connect the bottom of the post to new higher pier. My concern is that with New England’s freeze/thaw cycles, water will work its way between the two concrete sections, which when it freezes will ultimately crack the concrete.
Should I be concerned? If so, is their a way to prevent the water intrusion? Is their a better way to do the repair?
Thanks for you help.
Replies
IMO the reason the posts rotted out is because they were below grade AND in contact with the concrete. Concrete that is contact with damp earth is inheritently damp. IMO if you have a metal post foot on the bottom of the posts it helps a lot. BTW - how old are the rotted out posts? Back when PT lumber first came out for common use 4x4s were available in .20 treatment rate, but that was a long time ago. Personally, I'd much prefer to replace the posts
Can you saw them off and pour more concrete to get them out of the groun d?
Clean the concrete surface well and de dust it after you drill your pegs treat the surface with a bonding adhesive. You wont have to worry because almost no water will enter the area to cause any lifting to take place. All the rest of your plan is dead on. You can even skip the epoxy and just use lag shields if you like but either job is good.
I would put a post connector on existing and fill hole with stone instead of dirt.