How to Repair a Rotted Porch Post

Cut the post at least 6 inches above the infected area using a reciprocating saw. Make your cut into dry wood. It should be square to ensure a clean finish on the repair.

Sweep off the area to clean up the rotted wood. This will give you a clean surface to install the new post.

Measure the sides of the old post. Purchase a pre-made post that matches the size of the post or construct one from wood boards. Cut each side to fit.

Place a one and a half inch black plastic spacer on the concrete to build your new post. Nail the bottom part of the post to the spacer.

Construct the post around the wooden base. Cut the boards the exact length from the plastic spacer to the underside of the existing post. Slide the board into place and nail it at the bottom onto the wood. Continue nailing all the boards into place.

Measure trim pieces to attach to the plastic spacer to complete the post. The trim should match the trim on the other posts. Nail the trim into place.

Apply wood putty to all of the joints using a trowel. Allow it to dry overnight.

Sand the putty to remove any rough spots.

Paint a layer of latex primer along the new portion of the post. Allow it to dry for three to four hours.

Paint the post with an outdoor paint that matches the rest of your porch.