In residential roof construction, the terms “ridge board” and “ridge beam” are often used interchangeably, but they refer to two distinct components that serve different functions. Understanding the difference between them is essential for anyone involved in building, designing, or repairing a roof. Here’s a breakdown of the two, along with their specific roles in roof framing.

What is a Ridge Board?

A ridge board is a horizontal structural element that sits at the peak of the roof, running along the top of the roof’s rafters. It is a part of the roof’s framing system but does not bear significant loads on its own. Its primary purpose is to serve as a point of connection for the upper ends of the rafters. These rafters slope down from either side of the ridge board, meeting at the roof’s apex to form the peak.

Key Characteristics of a Ridge Board:

1. Non-load-bearing: The ridge board itself does not support the weight of the roof. It merely holds the rafters together at the peak.
2. Size and Material: Typically, a ridge board is made from dimensional lumber, often 2×6, 2×8, or larger, depending on the size of the structure. It is sized according to the span of the roof.
3. Functionality: It provides stability to the roof structure by preventing the rafters from spreading apart and helps with the alignment of the roof frame.

Ridge boards are most commonly used in common rafter roof systems, where the rafters are the primary load-bearing members. They help to maintain the geometry of the roof and ensure the rafters are correctly positioned.

What is a Ridge Beam?

A ridge beam, in contrast, is a structural element that carries the weight of the roof’s load. Unlike the ridge board, which is simply a connector for the rafters, a ridge beam is a load-bearing component that supports the weight of the roof structure, including the rafters, roof deck, and any additional loads (such as snow or heavy roofing materials).

The ridge beam typically acts as the highest support for the roof, transferring the roof load down to vertical supports (like posts or columns) or to the walls below. Ridge beams are more commonly found in roof systems with engineered framing, like those using scissors trusses or purlin-supported rafters, where the load is transferred from the ridge beam to other structural components.

Key Characteristics of a Ridge Beam:

1. Load-bearing: A ridge beam supports the roof load, including the weight of the rafters, roofing materials, and any additional structural loads.
2. Size and Material: Ridge beams tend to be larger and stronger than ridge boards. They can be made from wood, steel, or engineered lumber, depending on the design and the load requirements. The size of the ridge beam is determined by the span of the roof and the load it must bear.
3. Functionality: The ridge beam not only serves as a connection point for the rafters but also supports the entire roof structure and helps distribute loads to the foundation.

Ridge beams are often used in more complex or large roof designs, such as gable roofs with longer spans or roofs that require additional structural support due to heavy loads or unusual designs.

Key Differences Between Ridge Board and Ridge Beam

When to Use Ridge Board vs. Ridge Beam

• Ridge Board: A ridge board is appropriate for simpler roof designs, especially in homes with a conventional gable roof. If the roof’s span isn’t too wide or if additional support isn’t required for heavy loads, a ridge board is typically sufficient to hold the rafters in place.
• Ridge Beam: A ridge beam is used in situations where additional support is needed due to the size or complexity of the roof. For instance, when building a roof with a longer span or a steep pitch, a ridge beam ensures that the roof structure remains stable and that the loads are properly supported. Ridge beams are commonly seen in homes with vaulted ceilings, open floor plans, or roofs that require more advanced engineering solutions.

Conclusion

In summary, the ridge board and ridge beam serve different roles in roof framing. A ridge board acts as a simple connector for rafters in less complex roof systems, while a ridge beam carries substantial load and is often used in more intricate or larger roof designs. By understanding the specific functions and applications of each, homeowners and builders can make informed decisions about which component is best suited to their roof’s design and load requirements.