Are there12 foot deck railing spans

by Marc
(NY)

Are they any railing manufacturers that make a deck rail panel that can span 12 feet between posts? I am trying to make my life easier.

I would prefer metal, but would also consider composite if it is a long lasting no headache composite material.

The deck is only about 20 inches off the ground, 12x12. The frame is done but I am now deciding on the railing style and type first to determine post layout.




Editor's Comments:

I have never seen and standard manufactured railing panel or section that is designed to span 12'. The largest manufactured sections I have seen are 8'. Trex makes one and there are vinyl railing companies which do also.

Custom metal railing can be designed to span 12'

However there is good reason why you don't see companies making standard 12' railing sections and it has to do with how much more difficult it is to get the railing to meet the uniform and concentrated (point) loads at that span distance.

Even at 8', you will have to secure the posts into the joist framing using specialized fasteners and connector hardware to ensure the posts can handle the increase load now that they are further apart.

The further apart the posts, the more load each post must handle.

In addition the span itself must be more rigid than when it is at 6' because there are uniform or distributive loads based on each linear foot or railing. The top rail can only flex outward so far based on stringent standards.

Trust me when I tell you this because I have been in engineering test labs a lot while developing new post anchor products. There is a reason why the industry tends to work with 6' spans.

It has to do with the fact that wood is the most common material and because you can usually get each post to handle the load generated at those spans and railing height.

My recommendation:

With a 12' span put a middle post in at the 6' mark on each of the three sides of your deck and you will be fine. It will also look very nice.

Don't try to save a few dollars by having only corner posts on your deck. It will not look right and very likely will not meet building code guardrail performance standards.


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