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 opposing planes of the roof meet. Diving in further, you may also come across the terms ridge beam and ridge board, making you wonder what the difference between the two is.
In short, the ridge beam is a structural part of the roof required by building code, and a ridge board makes the roof installation easier. The ridge beam transfers the load to the posts or gable ends and is necessary when the slope is less than 3/12. The non-structural ridge board is used when the roof slope is between 3/12 and 12/12.
Confused? Don’t worry! We’ll dig deeper into the differences between a ridge beam and a ridge board so that you can better understand your roof installation.
First, Know The Type of Your Roof
Whether to use a ridge board or a ridge beam can depend on the type of roof you are putting on your structure. Here are the common roof types:
- Gabled Roof: two sloping sides that meet at the ridge and create triangular end walls.
- Gambrel Roof: Two-sided roof that has two symmetrical slopes on each side.
- Hip Roof: Roof with four gentle sloping sides.
- Mansard Roof: Roof with four double-sloping sides.
- Shed Roof: Also commonly referred to as skillion roofs. One sloping side that is often steep.
- A-Frame Roof: Roof with two steeply sloping sides that begin at or near the foundation and meet in a ridge giving the roof a shape like the letter “A”.
What Is Ridge Board?
A ridge board joins the rafter at the top of a structure in roofing. It is not load-bearing, and it is not a structural part of the building — it just holds the rafters together.
What Is The Purpose Of Ridge Board
The main purpose of a ridge board in a roof installation is to eliminate the need to balance the rafters against one another. A ridge board also negates miscalculation errors because it eliminates the need for precise positioning of rafters.
What Is Ridge Board Made Of
Ridge boards can be made from 1×8 boards, but they are commonly made from 2×8 or larger lumber pieces.
Where Is the Ridge Board Used?
When a roof has a slope of at least 3/12 but not over 12/12, a ridge board can be used. It is a non-structural prop that the rafters rest against where they meet at the peak of the roof.
How to Support a Ridge Board?
Since the ridge board does not carry any load, and it is only there to provide stability for placing rafters, it does not need to be supported.
How to Cut Ridge Board
When cutting a ridge board, you need to ensure that it is at least 1 inch thick. The depth should at least match the cut end of the rafters that will be attached to it. Remember, the cut depth will be greater than the rafter’s actual depth.
What Is Ridge Beam?
Unlike ridge board, ridge beam is a structural part of the roof, and it is load-bearing. They are required by building code if a roof has a slope less than 3/12.
What Is The Purpose Of Ridge Beam
A ridge beam can be stronger than a ridge board, and it can be easier to assemble in some instances. A-frame or gable roof designs use a ridge beam because the rafters need independent support.
What Is Ridge Beam Made Of
The lumber used to make a ridge beam is calculated using the roof load, roof size, and the span of the beam. The boards used will likely be at least 2×10, but they can be larger as well, depending on the calculations.
A roof design that requires a ridge beam should be checked by an engineer to ensure proper installation.
Where Is Ridge Beam Used?
You will find the ridge beam at the apex of the roof’s triangle. The ridge beam will span from one exterior wall to the other, and it will connect the rafters together.
How to Support a Ridge Beam?
Since the ridge beam is structural, it does need to be supported. It carries half the roof’s weight which is why it is commonly supported by a steel post or a masonry structure.
Can a Ridge Beam Be Spliced
Yes, a ridge beam can be spliced, but it must be done with care. In a structure with a roof that is longer than your average milled board length, it will be necessary to splice the ridge board. However, it is important that your splices are between your rafters and not where the rafter lands. A rafter that is nailed to the splice can lead to a weak spot in the roof.
Ridge Beam Vs Ridge Board: How to Decide Which One Your Roof Needs?
While it is true that homes that have stood for hundreds of years were made without either a ridge beam or a ridge board, you are likely going to use one or the other on your structure. If your home has a roof slope of less than 3/12, you will need to use a ridge beam. A ridge beam is also a good choice if you want to maximize attic space.
Should your roof have a slope that falls between 3/12 and 12/12 — and you don’t care about having lots of attic space — then a ridge beam may be the better choice.
Homes with vaulted ceilings or that feature exposed beams will also use ridge beams over ridge boards.
