Understanding the functionality of shingles and the minimum roof pitch requirements is vital for any roofing project. This article delves into the concept of roof pitch and the minimum slope necessary for different types of roof systems, including shingles, asphalt roof shingles, and metal roofs.
Calculating the minimum pitch of the roof has several benefits. In addition to adhering to building codes, it ensures that the roofs provide adequate protection for the living or storage areas beneath them.
Minimum Pitch for Shingles Definition
First of all, pitch refers to the angle (inclination) of the roof. To calculate a ratio, divide the vertical distance by the horizontal for every 12 inches/feet of vertical rise. By measuring the roof rise over its run, we can determine its pitch. While the rise is variable, the run remains constant.
If the roof pitch is 5/12, then every 12 inches of length will result in a 5-inch height rise. When the slope is 8/12, the height rises 8 inches for every 12 inches of length.
When the rise is higher, the roof pitch is steeper. When a roof has a 3/12 pitch, it has very little pitch, but when it has a 12/12 roof pitch, it will have a very steep pitch.
Read also: Snow Load Roof Pitch
Minimum Roof Pitch For Shingles
Ideally, the minimum roof pitch for shingles should be 2:12. A roof pitch of 2:12 will require underlayment around the eaves to install shingles.
For non-soldered panels and metal roof shingles, the minimum pitch is 3:12.
What is Asphalt Shingle?
Asphalt roof shingles are among the most prevalent roofing materials in North America, known for their resilience against harsh weather conditions and their ability to enhance home value. These shingles are a key component in many roof systems.
In addition to their ability to resist severe weather conditions, asphalt shingles are also affordable, simple to install, and versatile.
Generally, Asphalt roofs come in many different designs and colors. There are a variety of roof designs for homes, including sloped or angled ones. Also, there are other two common types of asphalt shingle, such as:
1. Architectural Shingles
First of all, architectural shingles consist of an additional layer of asphalt laminated to each of their lower portions. Laminating the surface gives the product a contoured, three-dimensional appearance. Sealant-bonded asphalt strengthens waterproofing capabilities. Though durable, these shingles are not ideal for low-sloped roofs susceptible to wind-driven rain.
2. Three-Tab Shingles
The second type is Three-Tab Shingles. Those with tabs and cutouts on their long lower edge are the most affordable and popular option. They look like three separate parts after installation.
Read also: Are Architectural Shingles Worth Extra Cost?
Minimum Pitch for Asphalt Shingles
According to the International Building Code, the pitch requirement for installing asphalt shingles is a minimum slope of over 2:12. This guideline ensures optimal performance and longevity of the roofing material.
In actuality, the minimum pitch recommended by some manufacturers is 2:12, not 4:12. It is impossible to cover a low slope or flat roof with asphalt shingles because water cannot sit or hold on them. As a result, asphalt shingles cannot be installed on roofs with pitches less than 2:12.
Taking the vertical rise of the roof and dividing it by the horizontal run, we can calculate the roof slope. If it has a 2:12 roof slope, it rises 2 inches for every 12 inches horizontally.
As a rule of thumb, three-tab asphalt shingles perform best on roofs with a 4:12 pitch or higher, but you may be able to get away with a 2:12 with additional protection.
For the installation of asphalt shingles, it is strongly advised to engage a professional roofing contractor. Without experience in roofing, there’s a risk of errors that could result in leaks and other complications. Adhering to installation instructions is crucial for the integrity of the roof.
For choosing the best roof material for a home or shed, determining the roof slope is essential, whether using asphalt shingles or metal. From there, you can calculate the minimum pitch for shingles you can use. Additionally, some local building codes may have specific requirements for minimum roof slope that must be followed