Posted by Shawn Hales on 5th Mar 2026
Common mistakes when choosing the right post cap for your project
Most people want their deck or fence to be an attractive addition to their home. Adding some complimenting accessories such as post caps or lighting that are not only easy for the DIY'er but offer a long lasting accent to their outdoor project are a couple of the easiest, with the dramatic effect home owners desire.
There are several styles and materials to choose from when selecting the right post cap for your fence or deck project, and not all are created the same. First there is the original wood post cap, which quality and type of wood used can range from extremely poor to extremely expensive. The majority of these caps are made from pressure treated pine, these tend to be made very poorly; using staples and glue to hold them together. Although these post caps look very nice when they first arrive, the life span of these products can range from just a couple of months if left unpainted or treated, to a few years with regular maintenance of painting or recoating in weather protectant. These wooden caps also tend to be more expensive then many other materials used today.
Atlanta Post Caps offers a line of UV stable polymer postcaps that are not only American made, but offer the longest guarantee in the industry, promising to outlast any traditional wood caps as well as most finishes on powder coated metal caps as well. With over 20 years of manufacturing fence and deck post caps, they offer almost every size post cap to protect your expensive wood or composite fence or deck. Atlanta Post caps carries both Nominal and Actual size post caps for 4x4, 4x6, 6x6, and 8x8 wood or composite post.

The most common mistake made by a person looking to buy post caps for their new fence or deck is assuming the size post cap they order without measuring the actual post size. Most people do not realize that for each size category (i.e, 4x4, 6x6 etc.) There are 2 available sizes. For instance a standard nominal 4x4 wood post actually measures approximately 3.5"x3.5" this can vary slightly due to moisture content in wood. This is also the most common size used in most fencing and deck projects. While in some cases an Actual 4"x4" post cap is needed, for applications using rough cut lumber such as cedar, or a sleeved wood post wrapped in materials like vinyl, composite or even concrete board.

Whatever product you decide to choose, make sure you take the time to measure your post and look at the dimensions of the the product you are buying before you order. When the builder tells you "the post are 4x4's" Just be aware he may not even know that there are 2 available options for each standard size. Enjoy your new fence or deck and remember Atlanta post caps for all your outdoor projects.