Both ridge boards and ridge beams are important to a roof’s structural integrity and overall design. While they may sound similar, they are used in different scenarios. This article will help you understand the differences so you can make better, more informed decisions about your roof.
Understanding Roof Ridges
According to the National Roofing Contractors Association, the ridge is the “highest point on a roof, represented by a horizontal line where two roof areas intersect, running the length of the area.” In simpler terms, it is the peak of a structure’s roof where the two sides of the roof meet.
Depending on the roof’s slope and design requirements, a ridge board or a ridge beam will be used for this junction. A ridge beam is a structural part of the roof required by building codes, and a ridge board makes the roof installation easier.
What Is a Ridge Board?
A ridge board is a non-structural component used in roof construction. It serves as a connecting point for rafters at the peak of the roof, providing stability during the installation process.
The Purpose of a Ridge Board
The primary function of a ridge board is to simplify the roof installation process. It eliminates the need to balance rafters against one another and reduces the risk of miscalculation errors. By providing a solid surface for rafters to rest against, a ridge board makes it easier to position and align the roof structure. This alignment is crucial for stability and even weight distribution, which is what helps your roof stand up over time.
Materials Used for Ridge Boards
Ridge boards are typically made from lumber. In some cases, treated lumber is used for added resistance against moisture and pests, which can prolong the lifespan of the roof.
The dimensions vary based on the roof’s requirements, but 1×8 boards are common for smaller structures, and 2×8 or larger pieces are used for bigger roofs.
When To Use a Ridge Board
Ridge boards are suitable for roofs with slopes between 3/12 and 12/12. In these cases, the roof’s pitch is steep enough that the rafters can effectively transfer loads to the walls. This makes ridge boards an ideal choice for residential homes and standard roof designs that do not require the additional support of a ridge beam.
Installing a Ridge Board
Since a ridge board is non-structural, it doesn’t require special support. However, proper installation ensures the rafters remain in place, reducing the risk of structural issues over time. Here are some key points to consider:
- The ridge board should be at least 1 inch thick.
- Its depth should match or exceed the cut end of the rafters.
- Secure attachment to each rafter is essential for stability.
What Is a Ridge Beam?
Unlike a ridge board, a ridge beam is a structural component of the roof. It’s load-bearing and is required by building codes for roofs with slopes less than 3/12.
Purpose of a Ridge Beam
A ridge beam serves as the primary support for the entire roof structure and transfers the roof load to the supporting walls or posts. Ridge beams are particularly important in designs such as A-frame or gable roofs, where rafters need independent support to stabilize the roof during weather conditions such as heavy snow or high winds.
Materials Used for Ridge Beams
Several factors determine the material and size of the ridge beam, including the roof load, roof size, and beam span. Typically, ridge beams are made from larger lumber pieces, often 2×10 or larger depending on the structural calculations.
In some cases, engineered wood products or steel may be used for additional strength. These materials can mitigate issues caused by moisture and improve long-term structural integrity.
When To Use a Ridge Beam
Ridge beams are required for the following types of roofs:
- Roofs with slopes less than 3/12
- Designs requiring maximized attic space
- Homes with vaulted ceilings or exposed beams
Supporting a Ridge Beam
Proper support gives the ridge beam enough strength to handle the roof’s weight, and makes your overall roof structure stronger and longer-lasting. Common support methods include steel posts, masonry structures, and load-bearing walls at each end of the beam. An engineer should verify the design and support of a ridge beam to ensure it meets local building codes and structural requirements.
Can a Ridge Beam Be Spliced?
Yes, a ridge beam can be spliced, but it must be done carefully. The ridge beam must be spliced when your roof is longer than your average milled board length. The splices should be between your rafters and not where the rafters land. Nailing a rafter to the splice can cause a weak spot in the roof.
How To Choose Between a Ridge Beam and a Ridge Board
Choosing the right ridge component determines the longevity and safety of your home. While ridge boards offer simplicity and cost-effectiveness for many standard roof designs, ridge beams provide the necessary support for more complex or low-slope roofs.
Consider these factors when choosing between a ridge beam and a ridge board:
- Roof slope: Use a ridge beam for slopes less than 3/12. Roofs between 3/12 and 12/12 can get away with a ridge board.
- Structural requirements: Ridge beams are necessary for load-bearing support, and ridge boards are sufficient for non-load-bearing applications.
- Architectural design: Ridge beams are ideal for vaulted ceilings and exposed beam designs, while ridge boards work well with traditional roof structures.
- Attic space: Choose a ridge beam if maximizing attic space is a priority, but a ridge board is suitable if attic space isn’t a concern.
A roof design that requires a ridge beam should be checked by an engineer to ensure proper installation.
Common Roof Types and Their Ridge Components
Different types of roofs need different support for their ridges. Here’s a breakdown of which ridge support each design should use.
Gable Roof
A gable roof features two sloping sides that meet at the ridge, creating triangular end walls. Depending on the slope, either a ridge board or beam may be used. The choice often depends on the design specifications, with ridge beams giving more support for lower slopes and ridge boards sufficing for steeper angles.
Hip Roof
Hip roofs have four gently sloping sides, which allow for good water drainage and wind resistance. They typically use a ridge board due to their steeper pitch.
Gambrel Roof
This two-sided roof with two symmetrical slopes on each side often requires a ridge beam for additional support. Gambrel roofs are commonly seen in barns and farmhouses, where the stronger support of a ridge beam helps manage larger spans and heavier loads.
Mansard Roof
A mansard roof is a gambrel-style hip roof with double-sloping sides. You can use either a ridge board or beam depending on how tall and steep you want the roof to be.
Shed Roof
Also known as a skillion roof, the shed roof’s single-sloping design doesn’t typically require a ridge component. The shed roof’s simplicity makes it an attractive option for modern, minimalist architecture.
A-Frame Roof
An A-frame roof has a steep slope resembling its namesake letter. This design is particularly common in vacation homes and cabins. The dramatic angles usually require the added support of ridge beams.
The Importance of Professional Assessment
While it’s useful to understand the basics of ridge boards and beams, you still need to consult a professional for your roofing project. Professional assessment minimizes risks and improves the longevity of the roof structure.
A qualified contractor or structural engineer can help you with the following tasks:
- Assessing the specific needs of your roof
- Ensuring compliance with local building codes
- Recommending the most appropriate ridge component
- Providing proper installation or oversight
