In regards to the installation of floor joists, what configuration is necessary to meet IRC requirements?

When it comes to the installation of floor joists, meeting the International Residential Code (IRC) requirements involves ensuring that the joists are properly supported and spaced. The correct answer highlights the need for multiple spans with consistent spacing, which contributes to the structural integrity and performance of the floor system.

Multiple spans allow the floor joists to distribute loads more effectively across several supports rather than relying on a single span, which could lead to excessive deflection or failure if not properly supported. Consistent spacing is equally crucial as it creates uniformity in load distribution, ensuring that the weight is evenly applied and that the joists work together as a cohesive unit to support the structure above.

In comparison, single spans might not adequately handle the load without additional supports, while a continuous span across multiple supports could introduce complexities in load distribution and might not align with IRC spacing requirements. Substituting with engineered wood products might be viable in certain situations but does not inherently satisfy the requirement for consistent spacing and load distribution modeled in the IRC typically aimed at traditional lumber joists.

Thus, acknowledging the importance of multiple spans and uniform spacing not only meets IRC prescriptive requirements but also ensures overall structural safety and durability in floor framing.