Using a hydraulic jack to lift a porch beam to replace a rotten column.
Using a hydraulic jack to lift a porch beam to replace a rotten column.

Exterior wood porch columns can deteriorate and rot over time due to exposure the elements. Replacing a damaged porch column isn’t that hard, but proper safety precautions need to be taken to avoid injury or damage to the porch.

To remove and replace a porch column:

  1. Attach a short 2”x 6” board to the end of a 4” x 4” post.
  2. Position a jack directly under the porch beam next to the column.
  3. Measure from the porch beam to the jack, and cut the 4×4 to just under this length.
  4. Position the post, and use the jack to raise the porch beam slightly until the old column can be removed.
  5. Check to make sure the porch beam is level by raising or lowering the jack.
  6. If you’re using a plinth block as the base of the column, position it in the same location as the old column, then measure from the top of the plinth block to the bottom of the porch beam.
  7. If you’re installing the new column directly on the porch floor, measure from the floor to the beam.
  8. Make sure one end of the new column is square, and cut the column square to length on the other end.
  9. If the bottom end of the column isn’t sealed, paint or apply sealant to it to prevent water from wicking up the column.
  10. Attach the plinth block to the sealed bottom of the new column.
  11. Set the new column in place in the same location as the old column.
  12. Use a level or plumb bob to make sure the column is plumb in all directions.
  13. Slowly release the jack to lower the beam onto the new column.
  14. Apply optional trim molding to the base and top of the new column.
  15. Prime and paint the column and molding with quality exterior paint.

Watch this video to find out more.

Further Information

VIDEO TRANSCRIPT
Exterior wood columns are often subject to water damage because of the exposure to the elements, but replacing them can be a simple chore. We’re tacking a piece of two-by-six onto one end of this four-by-four, which we’ll use to raise the beam that’s resting on the column.

A hydraulic jack beneath the four-by-four supplies the lifting power to raise the beam. For safety it’s important that the jack, post, and beam are aligned one directly over the other. With the weight removed, the rotten column can be removed.

The new column here is made from pressure treated lumber and will rest on a metal plinth block, so we measure from the block to the beam to determine the length of the new column before cutting it. This hollow, laminated column has a special factory sealant on each end. Since the sealant was cut off on one end, we’ll make that the top and attach the plinth block to the end with the sealant.

The new column goes into the same location as the old one. With the top in the corner, we move the bottom in and out and side to side until it is perfectly plumb. Then we slowly release the jack so the beam rests on the new column.

A few pieces of trim cover the metal plinth block and the whole thing gets a coat of primer and two coats of paint before it’d done.

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8 COMMENTS

  1. Hi, I had a few questions after watching your video about replacing a wooden porch column:

    1. Please explain the decision to let the weight of the porch secure the column in place vs anchoring it on top and/or bottom?
    2. There’s a gap left between the trimming and concrete, is this so that it keeps the trimming off the concrete and effectively out of any standing water?

    I thank you for sharing the video and would appreciate any comments or advice 🙂

    ,Matthew

  2. how about second floor posts, replacing 1st. floor jacking up second story roof structure; approximately 25ft. What type of jacks and supports and how many 20′ wide porch.

  3. Love the simplicity of the video! Will save me a bucket load of money on install and hopefully the columns as well. Can you tell me where I can go to get these columns? I live in GA about 50 miles south-east of Atlanta, so hopefully it will be close by. Many thanks!

    • Hi, Sharae,
      TodaysHomeowner.com features home improvement advice from the nationally syndicated TV show “Today’s Homeowner” and its experts.
      We don’t sell construction products on this website, but we encourage checking your local home centers for these materials.
      Good luck!

    • Hi, Matthew,
      Sometimes, in older homes, the columns are just secured by the weight of the load on them. However, new building codes require fasteners (and/or straps) to secure them at the top and bottom to protect the structure from wind uplift.
      Thanks for your question!

  4. Okay, I may need some help. In the middle of winter our insurance company pulled a fast one on us and said we needed a railing around our porch(2ft off the ground) or they would drop us and we had 30 days!?!?
    So I designed a fencing, and in the process found the porch column rotted and covered up with bondo. I decided since i was out in the cold i might as well do it right. SO i replaced all the columns as well. When I took off the old plynths,there was a metal plate covering the bottom of the columns hollow shaft. So i sized, cut and resealed the ends with paint and them put a piece of aluminum over the ends like the previous owner did. Now I see the column is splitting already. Should i poke hole in the bottoms to air it or?

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