Railings Make or Break a Deck
Railings on a deck are like wheels on a car. They can enhance the deck style, portraying a meticulously mastered piece of art. They can also give the impression of a carelessly slapped together piece of junk. Like I’ve preached many times before, make sure you know exactly what you’re getting when you purchase a deck. (see – Not all deck builders are the same. & Not All Johnson County, Kansas Decks Are Created Equal) Railings are often a prime area some deck builders will shortcut to save time and money. If not thoroughly and specifically described in a proposal, they deck railings can be built a number of ways to pass building code.
There are some very cheap deck builders in Kansas City and probably throughout the United States. Cheap deck builders will find the quickest and least expensive way to make your deck railings pass code, if you let them. This is typically done by turning a 2×6 board sideways and nailing balusters to the 2×6 board (which serves as both the deck guardrail and top cap). The bottoms of the balusters are fastened to the deck’s rim plate, or outer framework. You’ll often see this done on cheap spec homes and low grade home builder decks. I can’t name the number of times we’ve lost a job to this type of construction, and the homeowner has come back and said they had no idea this is what they were paying for.
Even basic railings should be made of at least five essential parts.
Posts are used to break up sections and provide lateral support. Posts should be 6”x6” timbers (unless using a composite sleeve over). The deck support (continuous from ground up through the railing) and intermittent (dummy) posts should be notched into the inside of the deck’s framework. Then they should be blocked in from all sides. Cedar and treated deck railings should never be spanned over ten lineal feet while composite should not exceed eight in length.
Deck rails are commonly made from 2”x4” or sometimes 2”x6” boards turned sideways and ran inside of the deck posts. The bottom deck rail should be held off the deck’s surface for aesthetics and ease of cleaning the deck surface. The rails should have a minimum of two fasteners, per board, per end, from the outside facing in. This ensures the 200lb. minimum lateral load capacity required by national building codes. Another fastener should be installed on the inside of the rail to keep the rail straight and help prevent twisting.
Railing top caps are generally made from 2”x4” or 2”x6” and help reinforce and strengthen the railing section. The top cap usually coincides in color and material with the deck surface even if the rest of the railing does not.
The squash block is installed between the bottom rail and the deck surface. The blocks keep the railing from sagging under its own weight. They are commonly installed one per railing, in the middle of the section. However, some deck builders put more than one per section. This usually depends on the type of materials used in the railing. The blocks can be made many different ways and most quality deck builders try to keep their block style original but in line with the deck theme.
The deck baluster or spindle can vary in size, shape, color, texture, and material. In fact, it’s safe to say that there’s and infinite number of spindle possibilities. Black round aluminum spindles are by far the most popular on decks in Johnson County, Kansas and throughout the Kansas City metro area. They provide a fairly open view while being maintenance free and very affordable due to their popularity. The important thing to remember is that no opening on top of the deck’s surface should be greater than four inches. On deck stairs, a six inch sphere should not pass through any place. These benchmarks are set so a child’s head cannot get stuck on top of the deck’s area. While the same does not apply to the deck stair area for construction practicality, the six inch clearance guideline prevents even the smallest child from falling through the stairs.
(On a side note, open risers are illegal on decks in Kansas City and should not be ignored!)
I’ve not even begun to cover glass, aluminum, iron, composite or PVC deck railings. That’s because these types of railings are usually sold as systems. They have already passed their own necessary code compliance testing. As long as installed properly, they’re already up to building code standards. Most of the prefab systems, like Radiance Rail from Timbertech, add some nice character to a deck’s look.
And that’s exactly what you need. Like a sports car with generic hubcaps, even the best built deck can look very plain without decent railings.
Hop this helps,
Dan Milford (DW Elite Decks - Kansas City deck builder)



