As the primary support system for the roof, roof trusses play a vital role in making sure your home is structurally sound. Homeowners looking to save time and money while making informed decisions about their roofing projects need to know the ins and outs of roof truss spacing. Keep reading to learn all about roof truss spacing, from standard measurements to cost considerations.
What Is a Roof Truss?
Roof trusses create a structural framework that supports a building’s roof by distributing its weight (including anything on it, like snow) to the outside walls of the building. Modern homes typically have trusses made of wood or metal that come in prefabricated forms or are custom built on-site to meet specific architectural requirements. Each building’s specific needs determine the design and configuration of the roof trusses.
Roof Truss Spacing: What You Need to Know
Most residential buildings have a standard roof truss spacing of 24 inches on center. To accurately measure the distance between trusses, measure one truss’s midpoint to the midpoint of the next.
Experts have designated the 24-inch spacing as the industry standard because It provides adequate support for most roofing materials and common loads and represents an appropriate balance between using enough trusses for proper support and minimizing material costs. Many roofing and insulation materials are designed to fit the 24-inch spacing.
What Factors Affect Roof Truss Spacing?
Several factors influence the proper spacing of roof trusses. Local building codes can vary, and different regions may have specific requirements based on your local climate conditions and building practices.
Steeper roofs may require closer spacing to handle increased loads, while heavier materials like tile may necessitate closer spacing or stronger trusses. Truss spacing may need to be closer in areas with heavy rainfall or if you store items in your attic, which adds weight to be supported.
If you plan on building a home, consult an expert to determine your roof truss needs.Â
Roof Truss Spacing for Different Roofing Materials
The type of roofing material on your home can significantly impact how far apart trusses should be. This section will explore how spacing may vary for different roofing options.
Metal Roofing
More homeowners are choosing metal roofing because it’s durable and energy efficient. For metal roofs, the standard 24-inch spacing is often enough, but roofing panel profile, the need for wind resistance, and the amount of insulation installed influence the spacing needs. Some metal roofing panels may need closer spacing for optimal support.
Shingle and Tile Roofing
For traditional asphalt shingles, the 24-inch spacing standard typically works well, but for heavier materials, such as clay or concrete tiles, you may need trusses spaced 16 to 20 inches on center to provide enough support. Slate roofing can sometimes need spacing as close as 12 inches on center.
Check out this video for further details on roof truss spacing:
Wood Shake Roofing
The truss spacing for wood shake roofs is typically around 24 inches on center, but the quality and treatment of the shakes influence spacing requirements. Treated shakes can usualy use the standard 24-inch spacing. Untreated shakes may need closer spacing because they vary in strength and thickness.
Pole Barn Truss Spacing
The different designs of pole barn roofing mean there’s no standard for how far apart roof trusses should be. Place trusses anywhere from 4 feet to even 12 or 16 feet apart, depending on the roofing material used.
Work closely with an expert to ensure the truss spacing for your pole barn roof will support your roofing material.
How Do I Determine How Many Roof Trusses I Need and the Costs?
Calculating the number of trusses you need can be challenging but the average homeowner can do it.
Start by measuring the length of the building in feet, then convert it to inches. Divide this number by the truss spacing and round up to the nearest whole number. Add one to account for the truss at the front of the building.
To determine the cost, contact your local building supply store and request quotes for your trusses, including slope, span, and spacing. For example, if your supplier will sell you trusses spaced at 24 inches on center for $4 per linear foot, and your trusses are 30 feet long, multiply 30 feet by $4 per foot, coming to $120 per truss. Then, multiply the total feet in length by 12 to find the size in inches. If the building is 30 feet long, this equates to 360 inches.Â
Then, divide the length of the building (360 inches) by the space between trusses (24 inches) to determine the number of trusses you will need. In this case, 360 divided by 24 equates to 15 trusses. Don’t forget to add 1 to account for the truss that will align with the edge of the building. So, for this example, you would need 16 trusses.
When dealing with multiple roof sections, you may need to calculate truss requirements for each section.
Our calculation provides only a general estimate—always consult with a professional to ensure the correct number of trusses for your specific project.
