Selecting Lumber for a Cable Railing Frame or Top Rail

Cable railing can be installed on a wide variety of wood products, but several considerations should be addressed in making your section. The first consideration for most people is budget and based on the scope of the project, wood choice can present thousands of dollars in cost difference. In considering your budget, also consider the life of the wood products and the annual maintenance cost.

Pressure Treated

The most popular lumber we see used for deck railing frames is PT (pressure treated). Most PT lumber is made of soft wood, usually southern yellow pine, that is relatively inexpensive compared to other species. The treatments provide protection against the elements that soft pine doesn’t have naturally. When selecting a pressure treated lumber, keep in mind that the chemicals are not something you would want to expose people to on a consistent or saturated basis. For this reason, we recommend using a KD (kiln dried) product for exposed wood frames. High quality pressure treated lumber, #1 or better, can look very nice and provide good value. There are also different types of treatment and different chemicals used based on region and purpose. The highest grade of treatment is “Ground Contact” which is meant to be used for pilings, building sills, and other conditions where the material is anticipated to be in contact with the ground. This is not an ideal product for railings as the wood will be exposed to excessive handling by people.

Many people wrap or sleeve PT with vinyl or composite material in which case the grade of lumber is not as important. A #2 PT may work fine in this application. The cost of these cladding materials also vary widely, and in many cases, the combined cost ends up being closer to higher end lumber. If wrapping or sleeving posts, do so because it provides the look you want, as the perceived savings may not be as much as it appears. Perceived maintenance is also a valid influence in choosing a sleeved or clad design.

There are some very specific requirements that should be followed when using a PT product as a top rail.  These requirements have to do with building the frame to ensure the railing has minimal opportunity to warp, twist or sag. This is covered in our installation instructions.

We never recommend PT for a top rails on our Spectrum, Latitude or other Atlantis Rail system that utilizes wood as the top rail.

Other Softwood Species

Cedar and Douglas Fir are two other very popular woods used in cable railing. They both have natural defense against the elements and insects. They are more expensive and more popular in certain regions. Both woods are native to the Northern US and Canada. Pricing varies by type and Douglas Fir is usually the lower priced product. Both will work very well for building a cable railing frame and both likely require annual maintenance to maintain their appearance. Douglas Fir and Cedar both age well and some people like the natural aged look. There are some designer aging techniques for both species. If you like the aged look, it reduces maintenance requirements.

Hardwoods

The most aesthetically pleasing lumber we see used is various hardwood species. Mahogany is the most popular because of price point, durability and appearance. Mahogany is a straight grained wood of reddish-brown color that maintains its shape and appearance, but it does usually require annual care. Mahogany is an excellent choice for cable railing due to its ability to maintain shape under cable tension. Prices and quality of mahogany vary considerably. Ipe is another favorite, but there are at least 7 species and they have different characteristics. Some are very close in appearance to Mahogany, and other are yellowish and naturally turn grey. Ipe in general is even more hardy than Mahogany and depending on climate, can last 25 years with minimal maintenance.

Choosing Your Wood

We suggest you start with your budget and work out from there to get an appearance you will be happy with. Then consider maintenance and other factors. 

Remember, inexpensive post sleeves, cladding and rails will likely look inexpensive at some point in time, and high-end cladding, sleeves and rails can be just as expensive as high end lumber. Good quality wood, even PT, can usually be maintained and revived to last for years.

Your deck is an outdoor living space that is a culmination of a safe and sturdy structure and framing, a floor and lastly the railing, which will be the most visual element of your new outdoor living space.