In roof construction, the ridge is the highest horizontal part where two sloping roof planes meet. To support this junction structurally and ensure the roof’s overall stability, builders use either a ridge board or a ridge beam. While the terms may sound similar, they serve distinctly different structural purposes. Understanding the difference between a ridge board and a ridge beam is essential for architects, builders, engineers, and even homeowners involved in new construction, renovation, or structural evaluations.
This article explores what ridge boards and ridge beams are, how they differ, when each is used, and the roles they play in modern roof framing systems.
What Is a Ridge Board?
A ridge board is a non-structural, horizontal framing member located at the peak of a roof. It serves as a nailing surface for opposing rafters but does not bear any significant load beyond the weight of the rafters themselves.
Characteristics of a Ridge Board:
- Typically made from dimensional lumber (e.g., 2×6, 2×8, or 2×10)
- Not engineered to carry vertical roof loads
- Must be at least the same depth as the rafters it supports
- Used primarily in conventionally framed (stick-built) roofs
Function of a Ridge Board:
- Provides a central alignment point for rafters
- Aids in roof layout accuracy and installation
- Helps stabilize rafters laterally during construction
- Makes rafter installation quicker and more precise
While it simplifies rafter placement, a ridge board alone does not transfer loads down to the walls or foundation. Therefore, in roofs using a ridge board, the system relies on opposing rafters and ceiling joists to provide structural resistance against outward thrust.
What Is a Ridge Beam?
A ridge beam, in contrast, is a structural, load-bearing member used to support the upper ends of rafters. It carries vertical loads from the roof structure down to supporting walls or posts, making it an integral part of the building’s load path.
Characteristics of a Ridge Beam:
- Can be made from engineered wood (e.g., LVL), solid sawn lumber, or steel
- Designed to bear the roof load (dead load and live load)
- Requires structural support at both ends (posts, columns, or walls)
- Common in modern and open-concept designs
Function of a Ridge Beam:
- Bears the vertical load of the roof where rafters terminate
- Eliminates the need for opposing rafters or collar ties to resist thrust
- Allows for cathedral or vaulted ceilings without ceiling joists
- Offers architectural flexibility for wide-open interior spaces
In structures with ridge beams, each rafter is independently supported and transfers its load directly into the beam, which in turn transfers that load vertically into the building’s support system.
Key Differences Between Ridge Boards and Ridge Beams
| Feature | Ridge Board | Ridge Beam |
|---|---|---|
| Structural Role | Non-load-bearing | Load-bearing |
| Material | Dimensional lumber | Engineered wood, steel, or heavy timber |
| Roof System | Requires opposing rafters | Rafters can be independent |
| Use in Vaulted Ceilings | Not suitable | Ideal |
| Load Distribution | Lateral thrust resisted by ties | Loads transferred vertically |
| Support Requirements | No vertical support needed | Must be supported at both ends |
When to Use a Ridge Board
A ridge board is commonly used in traditional homes and standard gable roofs. It is appropriate when:
- The roof has a moderate to steep pitch
- Opposing rafters can meet at the ridge and be tied together with ceiling joists
- The building is relatively narrow (spans under 30 feet are common)
- Structural simplicity and cost savings are desired
Building codes, such as the International Residential Code (IRC), allow the use of ridge boards in conventionally framed buildings, provided the framing includes opposing rafter pairs and ceiling ties or other horizontal restraints.
When to Use a Ridge Beam
A ridge beam becomes necessary when:
- The roof has vaulted ceilings or cathedral-style interiors with no ceiling joists
- The rafters do not have opposing pairs (as in mono-pitch or shed-style roofs)
- The building has a wide span that exceeds the limits for traditional framing
- The design calls for large open spaces without intermediate supports
Ridge beams are more complex to install due to the need for engineered calculations, larger materials, and vertical support elements. However, they offer unmatched flexibility for creative and open-concept architectural designs.
Structural Considerations
Ridge Board Roofs:
- Opposing rafters create a triangle with the ceiling joist
- The load is spread outward and downward onto exterior walls
- Collar ties or rafter ties may be used to prevent spreading
- Suitable for conventional framing practices and small-to-medium spans
Ridge Beam Roofs:
- Each rafter sits independently on the ridge beam
- Load goes straight down into posts or walls
- No horizontal ties needed, freeing up ceiling space
- Must be engineered to support both dead and live loads (e.g., snow)
Installation Considerations
Installing a Ridge Board:
- Cut and install wall plates at the top of opposing walls
- Place the ridge board between temporary supports at the desired ridge height
- Install rafters, aligning and nailing them to the ridge board
- Add ceiling joists to tie rafters and prevent lateral spread
Installing a Ridge Beam:
- Engineer and size the beam based on roof span and expected loads
- Install vertical posts or walls to support each end of the beam
- Secure the ridge beam level and in position with temporary bracing
- Install rafters, attaching them securely to the beam with approved connectors
In both cases, fasteners, hardware, and bracing must meet building code requirements. Ridge beams especially require special connectors, such as Simpson Strong-Tie brackets, to ensure structural integrity.
Building Code Compliance
The IRC and IBC both distinguish between ridge boards and beams. Here’s a simplified view of code implications:
- Ridge Boards: Must be at least as deep as the cut end of the rafters; not structural
- Ridge Beams: Must be sized and supported per structural calculations, often requiring approval from a licensed engineer
Always check local codes and consult with a structural engineer for spans over 30 feet or when deviating from standard framing methods.
Conclusion
Whether you choose a ridge board or a ridge beam for your roof framing depends on several factors—architectural style, span, ceiling type, load requirements, and budget. Ridge boards are common in traditional, stick-framed homes and rely on a triangular framing system to maintain structural integrity. In contrast, ridge beams are essential for more open, vaulted designs and function as primary structural elements capable of carrying heavy loads.
Both elements play a central role in ensuring that your roof is not only functional and safe but also aesthetically aligned with your overall architectural vision. Understanding the differences helps builders, architects, and homeowners make informed decisions about how to best support the roof—and the rest of the building that depends on it.
