What minimum nominal depth to thickness ratio is required for floor and ceiling framing to have one edge held in line for the entire span?

The minimum nominal depth to thickness ratio for floor and ceiling framing components, when one edge is held in line for the entire span, is pivotal in ensuring structural integrity and performance. A 5:1 ratio means that for every 5 units of depth, the thickness must be at least 1 unit. This ratio is designed to facilitate stability and prevent issues like buckling or excessive deflection, which can occur in poorly proportioned elements.

In framing applications, having a nominal depth to thickness ratio of 5:1 ensures that the elements can adequately carry loads over the span while also accommodating various factors such as material properties and environmental stresses. This specific ratio reflects established engineering principles and standards that take into account the material behavior under loading conditions.

The other ratios mentioned, while they may refer to different construction scenarios or requirements, do not align with the established guidelines for floor and ceiling framing under these specific conditions. A higher ratio, such as 8:1 or 12:1, would typically be reserved for different applications or requirements that necessitate greater depth for structural reasons.