What is the primary purpose of using a rim board in construction?

The primary purpose of using a rim board in construction is to support floor joists. Rim boards are installed at the edges of floor systems to provide a stable platform for the ends of the joists. They help create a solid and level perimeter for the floor structure, which is essential for maintaining the integrity of the entire flooring system. By supporting the joists, rim boards contribute to the overall strength and stability of the floor, helping to distribute loads evenly and prevent sagging or movement.

Creating a finished edge, framing window openings, and anchoring the roof are important aspects of building and carpentry but do not directly relate to the role of rim boards. Rim boards are not designed solely for aesthetics, such as finishing edges; instead, they serve a specific structural purpose in supporting the horizontal members of the floor frame. Similarly, while they may be involved indirectly in certain framing situations, they are not primarily used for framing window openings or for roof anchoring.