Stair Stringer Terminology: A Comprehensive Guide

Stair stringers, the backbone of any staircase, are crucial components that support the treads and risers. Understanding stair stringer terminology is essential for anyone involved in staircase construction, renovation, or maintenance. Let's delve into the key terms that define these vital elements.

Stair stringers, also known as stair bearers, are the supporting members that run vertically along the sides of a staircase. They bear the weight of the staircase users and transfer it to the structure below. Stringers are typically made of wood, but other materials like steel or concrete can also be used.

Stair Stringer Types

The first step in understanding stair stringer terminology is familiarizing oneself with the different types of stringers.

1. **Cut Stringers**: These are the most common type of stringers. They are cut with a series of notches along their length to support the treads. The notches are typically cut at a 45-degree angle to provide a strong, secure fit for the treads.

Notched Stringers

Notched stringers are a subset of cut stringers. They are characterized by the notches cut into the stringer to support the treads. The notches can be cut at different angles, with 45-degree notches being the most common.

Notched stringers can be further categorized into two types based on the number of notches:

• Single Notched Stringers: These have a single notch for each tread. They are typically used in straight staircases.
• Double Notched Stringers: These have two notches for each tread, one on each side. They are used in staircases with landings or turns.

Welded Stringers

Welded stringers are typically made of steel and are used in industrial or commercial settings. They are constructed by welding steel plates together to form the stringer shape. Welded stringers can be designed to support heavier loads than wooden stringers.

Welded stringers can also be notched to support the treads, similar to wooden stringers. However, they are often designed with a flat surface for the treads to sit on, with the treads being welded or bolted to the stringer.

Stair Stringer Components

Understanding the components of a stair stringer is crucial for accurate construction and maintenance.

1. **Tread Bearer**: This is the part of the stringer that supports the tread. In notched stringers, the tread bearer is the surface of the stringer between the notches. In welded stringers, it is the flat surface where the tread sits.

Tread Bearer Width

The width of the tread bearer is an important measurement. It determines the width of the tread and, consequently, the width of the staircase. The tread bearer width should be consistent throughout the staircase for safety and aesthetic reasons.

The width of the tread bearer is typically measured from the outer edge of one stringer to the outer edge of the other. This measurement should be consistent with the width of the risers and the treads.

Stringer Depth

The depth of the stringer refers to the vertical distance from the top of the stringer to the bottom. This measurement is crucial for determining the rise of the staircase, which is the vertical distance between each tread.

The stringer depth should be consistent throughout the staircase. It is typically measured from the top of the stringer to the bottom of the last tread bearer.

Understanding stair stringer terminology is not just about knowing the names of the different parts and types of stringers. It's about understanding how these components work together to create a safe, functional, and aesthetically pleasing staircase. Whether you're a homeowner planning a renovation, a contractor building a new staircase, or a maintenance professional ensuring the safety of an existing staircase, a solid understanding of stair stringer terminology is essential.