How is this plan for repairing load bearing rotting posts with epoxy (pics included)

epoxyload-bearingpost

My carport has five 4×4 posts with two of them are showing serious signs of rot. I have attached a photo of the worst and 2nd worst looking one, and what the other ones look like. At first I thought the only way to repair the posts was to replace them. However some epoxy’s have incredible bonding stength, load bearing strength and water resistance properties. My plan to repair them with epoxy as follows:

  1. On each side of the post, cut the blacktop a couple inches away from the post, and expose the full length of the post.
  2. Remove as much rotting material from the posts as possible with a small chisel
  3. Liberally Spray a wood preservative solution of copper napthenate (green preservative) to halt the rot’s progression
  4. Prebuild forms that will be put around the posts once the resin mixture is ready, and spray them with silicone spray so they will come away from the resin a little easier.
  5. Mix West Systems 105 Resin with West Systems 206 Slow Hardener, and thicken the mixture with West Systems 403 Microfibers. Note, I may not necessarily use West Systems products, but something similar such as from conserve: http://conservepoxy.com/category/Rot-Repair-Epoxies.htm .
  6. Let the Resin cure for a day or so and remove the columns.
  7. Prime and Paint the posts, including the repaired area.
  8. Repair blacktop and raise the blacktop enough such that rain water will slope away from the posts.
    I got this idea from a blog here: http://www.westsystem.com/ss/saving-the-deck/

What do you think, is my plan sound?

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Best Answer

The plan will make the 4x4s look good. However, you did say they are LOAD BEARING, an epoxy is great for holding things together or protecting things, but terrible at withstanding stress from a load. The posts function is to transfer the weight above it to the ground, so filling in the rotted parts of the wood with epoxy is just hiding the problem. Most epoxy adhesives rely on the stress being directed against thier cohesion to the material. When the stress is in a direction that is contrary to that the epoxy fails. If you wanted to glue two pieces together to double the load bearing capacity it would work great for that, but it can't take the load and replace the structural member yet. Maybe in the near future they will come up with something that can. Sorry to tell you this, but you are going to have to replace the 4x4 posts, or you run the risk of them tipping, or collapsing so that the structure comes down. It aslo would be a good time to bring them up to code. The good news is you can treat them so they are rot resistant for far longer now, and it is far cheaper than having the carport fall on your transportation.

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