Why do posts rot in the ground?
Three things are necessary to cause rot. Moisture, Oxygen and the sugars occurring naturally in the timber add up to rot. This rot is worse near the surface of the ground since that is where the maximum moisture and oxygen exist.
If you are thinking that a sonotube will work better… think again. Without the post extending into the earth as leverage—fences and second level decks won’t have as much lateral support. They will lean in short order without additional bracing. Lets face it, braces on a fence? The other problem--Concrete retains moisture and actually helps rot happen faster.
Use an expoxy coating or exterior stain to seal the post prior to installation. This should extend the life 5-10 years beyond the normal 10-20 years.
Post Protector tm with silicone sealant around the upper edge is a permanent solution. This membrane is similar to the material used beneath dumps to prevent chemical infiltration into the environment. Post protectors will also protect your posts against trimmer damage. Available in 4x4, 4x6 and 6x6 sizes, they are suitable for decks, fences, arbours and pergolas. Click here for more information.