Titan 4x4 Post Anchor Maximum Post Height
(Lake Forest, CA)
I plan on building a 6' horizontal privacy fence on top of my 5' retaining wall and I would like to use the Titan 4x4 post anchor with 4x4 redwood posts.
If I were to space the posts 6 feet apart and run 1x4 panels (spaced 3/8" from each other) perpendicular to each post from top to bottom, do you think the Titan 4x4 anchor would hold the 4x4 posts in place?
If not, how high do you think I could go? What if I spaced each post 4' or 5' apart? What if I used a Titan post brace on each side of the post? Initially, I wanted to use the 6x6 post anchor, but my retaining wall is 7.5" wide, which is the same width of the 6x6 post anchor. Thanks!
The 4x4 Titan Post Anchor are designed and engineered for residential guard rails, not fences. So the residential engineering guidance is based on 36" posts built into wood railings as shown on the instructions at 6' on center post spacing.
When you go beyond those limits, it cannot be used as a guardrail per se. So if you are using it for a privacy fence and the elevation difference between the adjacent surfaces is 30" or more you may well have a situation where it must perform like a railing would have to.
Keep in mind, this does depend on whether the area you are building and installing on fits this definition where guardrails would be required. Nonetheless, it is wise to consider that as you double the height of the posts and rail you double the leverage generated at the base of the post.
And if you are looking for identical performance at 6' high as you would get at 3' high you will be disappointed. A post brace will add between 25-30% more lateral resistance strength but it still will not feel the same as at 36". This will be exacerbated as you increase the post spacing to 8'.
Reducing the post spacing to 4' or 5' will improve things somewhat. However, the more common solution is to use a 6x6 post anchor at 6' and maximum 6' on center post spacing. This has been done with fences on concrete retaining walls and performed very well.
A Nice Addition To The Titan Post Anchor Family For 2017
There is a new post anchor coming out very soon that the folks at Titan Building Products have been developing over the past three years. It is a remarkable advancement as it is smaller than the periphery of a post and yet stronger than anything the industry has ever seen. It is part of the new Evolution line of products and is designed for really super high performance needs like what you are asking for. You can contact them directly to find out more.