Happy New Year everyone!!! May 2012 bring you many blessings and much enjoyment in your home.
A good deck post footing is key to supporting your deck. One of the old methods was to dig a hole (legally to below frost depth of 42") set the post and fill with concrete. The new method is to dig a hole to below 42", bell out the bottom just a little and fill with concrete to above grade and anchor the post to the new concrete pier with a post anchor. Mixing the two methods is not the best idea.
In the photo below we see an attempt to make a pier. The minimum diameter of a pier should be 8". I prefer 12" diameter. Obviously this one is shy of that mark. To make matters worse the builder put the post into the concrete. Well, as you can see the concrete broke. Here's why....
1. There is not enough concrete around the post. A few more inches would have helped a bit, but mother nature would have torn it apart anyway.
2. Notice the small gap between the post and the concrete. This allows water to seep in and when it freezes this pops the concrete loose. I was unable to see how far down the post went, but it has been my experience that some builders (or weekend warriors) don't dig all the way to frost depth. This was not the way to set this post.
The preferred method is shown below. Notice that water will drain away, the pier is fully supported to frost depth, the anchor keeps the post attached to the footing and the deck stays in place and YOU stay on the deck with all of your party guests.
By ensuring that the deck is bearing on a footing below frost depth keeps the deck from heaving in the winter due to frost and over time working its way loose from the house. Yes, this does happen. I had to fix one last winter. The home builder only put the posts 32" in the ground with NO concrete piers. While this isn't the photo from that job this is what will happen.
Digging a pier footing to the proper depth can be difficult at times, but it is REQUIRED and very, very necessary. This is not a place to cut corners. The entire rest of the project bears on this part of the project. Do it right. Do it once. Enjoy it forever.
Hitting Home Blog
Jon Bronemann - author of "The Hitting Home" blog. Check it out and you will see what I see everyday and why hiring a quality contractor is so very, very important. Seeing is believing and it really does "Hit Home".