You'd expect to see rotting wood in the bases of columns that are centuries old. But I was recently on a project in Chattanooga, Tenn., where I had to replace columns that were only 27 years old. Decay had started to show up 15 years ago. Faulty installation caused the column bases to rot prematurely. You can slap columns in place and forget about them. But sooner or later—probably sooner—you'll be reminded that a little more care with installation would have saved lots of trouble. Here are a few of the techniques I've developed for installing columns that will last. These methods are good for hollow columns up to about 15 feet tall. Preparation Repair the porch deck and pedestal structure