The former refers to inclined rafters extending from a ridge beam to the wall plates. The two most common types of residential roof frames using rafters are the ridge beam system and the collar tie system. Structural Analysis Systems of typical rafters Cold-formed steel rafters are particularly advantageous when longer spans or unique roof designs are necessary. They are lightweight yet strong, making them suitable for both residential and light commercial projects. Cold-Formed Steel RaftersĬold-formed steel rafters are made from thin-gauge steel sheets that are bent or rolled into the desired shape. Steel rafters are commonly used in larger structures, such as commercial buildings and industrial facilities, where longer spans and heavier loads are required. They are typically fabricated from structural steel sections and are known for their high load-carrying capacity. Steel rafters offer exceptional strength and durability. Wood rafters are suitable for most residential and light commercial applications and are often preferred for their aesthetic appeal. They are commonly made of dimensional lumber or engineered wood products. Wood rafters have been widely used in construction for their strength, durability, and ease of installation. Different Materials for Roof Rafters Wood Rafters They are crucial components in constructing portal frame buildings, which are widely used in commercial, industrial, and agricultural applications.įigure 3: Commercial portal frame building. It serves as the primary load-bearing element that spans between columns, providing support to the roof as well as lateral stability.

Portal frame rafters are structural members within a portal frame system. They provide additional support to the roof and help distribute the load evenly. Jack rafters are shorter, inclined members that connect the common rafters to the hip or valley rafters. They join the ridge to the eaves and help support the weight of the roof in these critical areas. Valley rafters are inclined members that run along the internal angles formed by the intersection of two roof surfaces. Hip rafters are commonly used in hipped roofs and are essential for distributing the load from the roof to the walls. They provide support and stability to the roof's hips (external angles formed by the intersection of two roof surfaces). Hip rafters are diagonal members that connect the corners of a roof to the ridge. Common rafters form the basic framework upon which other types of rafters are installed. They extend from the ridge to the wall plate and are typically evenly spaced along the roof's length. Common RaftersĬommon rafters are the main load-bearing members in a roof system. A few examples of the types of rafters used in construction are listed below.įigure 2: Common rafter types of a house roof framing. The specific design and configuration of rafters will depend on factors such as roof’s shape, slope and the structural requirements of the building. By distributing the load evenly, rafters ensure that the structure remains stable and can withstand various external forces, such as wind and snow loads.

The primary function of rafters is to transfer the weight of the roof to the walls or other load-bearing elements of the structure. They are inclined beams that extend from the ridge of the roof to the eaves and support the roof covering material, such as shingles or tiles.įigure 1: An example of exposed timber rafters landing on a lintel. Rafters are structural elements that form the framework of a roof. But have you ever wondered how it stays up there without crashing down like a house of cards? Picture this: you're standing beneath a roof, admiring its structure. So, grab your hard hats, dust off your drafting pencils, and let’s raise the roof, both literally and figuratively. We will also discuss different materials used for rafters, such as wood, steel, and cold-formed steel, along with practical tips for rafter design and analysis. In this article, we will explore the definition, function, and various types of roof rafters, including their unique features and applications. They are essential components that provide strength and support to the roof system.

Rafters play a crucial role in supporting the roof, distributing its weight evenly, and ensuring the overall stability and integrity of the structure. In any structural design project, the importance of roof rafters cannot be overstated.

Even though roof trusses are more commonly used than rafters, they do not provide the same versatility and space for creativity that rafters allow. Choosing the right “hat” for your building will depend on several factors, such as wall layout, ceiling type, and architectural features.

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