Get matched with top stair service pros in Buttonwillow, CA

Building exterior porch steps requires wood or material that can handle exposure to the outdoor elements. Use pressure-treated lumber for the stringers and pressure-treated cedar, outdoor-rated wood, or composite decking material for the rest of the structure.

The four-inch ball rule, also known as the four-inch sphere rule, is a safety requirement for railings on structures like decks and stairways. It states that a four-inch sphere should not be able to pass through any gap in the railing system. This applies to the spaces between balusters or spindles, as well as the gap between the bottom rail and the deck surface. The purpose of this rule is to prevent small children and pets from accidentally squeezing or slipping through the railing.

The standard distance between deck stair stringers is 12 to 16 inches. However, these numbers vary by building material, so reference the maximum span for the material. For example, some composite materials call for a maximum distance of 10 inches to maintain their structural integrity. 

As a general rule, never leave more than 16 inches of space between your stringers. Deck stairs have higher load-bearing demands than the walking surface of the deck, so it’s important not to overshoot the space between your stair stringers.

Most building codes require that railing spindles (also known as balusters) on decks or stairs be spaced no more than four inches apart. This safety standard is often called the '4-inch sphere rule,' which means a sphere with a 4-inch diameter should not be able to pass through the opening between balusters. This rule is in place to prevent small children and pets from slipping through the railing. For the same reason, the space between the bottom rail and the deck or floor surface should also be no more than four inches. As a general guideline, professionals often install three balusters per foot of railing. However, since specific requirements can vary by location, it is essential to check your local building codes to ensure compliance before starting your project.