Re: Porch post: what's best construction?
I believe I would opt to install a post to carry the weight of the roof, then install the decorative materials around it. This way you can isolate everything from the concrete patio.
Go with a 4x4 and set a post base into the concrete, I've always used a Simpson AB44 anchored with an expansion bolt. The post base has a plate the stands the post off the cement by 1", preventing the wicking of moisture and rotting of the post. The post can be standard structural grade material, it does not need to be pressure treated or specialty species.
Next attach spacers to the post that will support the decorative shell. Cut the shell and trim pieces and paint ALL surfaces and ends before installing on the post, this will help with stability issues. Keep the bottom plinth off the concrete by 1/4" - 1/2" then install a synthetic quarter round or shoe molding that will contact the concrete.
Caulk it all up really good and fill the fastener holes, then give it a final coat of paint.
If you want to avoid the problems of expansion/contraction and moisture altogether, you can install a synthetic column. These come in a multitude of designs and are structural, so no inner post is necessary in light duty situations. These columns can be a little expensive, but when compared to the problems that you've described and the time difference in the installation and maintenance, they may be the better choice for your situation.
Last edited by A. Spruce; 02-11-2012 at 11:33 AM.
I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!