What is the maximum span for typical wood joists?

The maximum span for typical wood joists can vary depending on several factors, including the type of wood used, the size and spacing of the joists, and the load they are designed to carry. However, a maximum span of 25 feet is generally considered reasonable for common configurations of wood joists when properly sized.

In practice, spans of up to 25 feet are achievable for larger joists or engineered wood products, such as I-joists or laminated veneer lumber, which can carry significant loads over longer distances compared to traditional solid sawn lumber. Designers must also consider the live load, dead load, and applicable building codes when determining the appropriate span, ensuring safety and structural integrity.

Choosing spans that exceed 25 feet typically necessitates additional design considerations, such as the incorporation of beams or supports, which are not typically required for spans that are 25 feet or less. This makes the 25-foot span a practical upper limit for traditional wood construction in many scenarios.