The size of lumber used for mounting rails in shelves and cabinets can vary depending on the weight and load-bearing requirements of the shelves or cabinets. As a general guideline, the lumber for mounting rails is typically chosen based on the following considerations:
Load Capacity: Consider the weight of the items that will be placed on the shelves or stored in the cabinets. Heavier loads will require thicker and stronger lumber to support the weight.
Span Length: The length of the mounting rail and the distance between support points (e.g., wall studs) will also influence the choice of lumber size. Longer spans may require thicker lumber to prevent sagging.
Wood Type: Commonly used wood types for mounting rails include pine, fir, oak, or plywood. Hardwoods generally provide more strength and durability compared to softwoods.
Shelf or Cabinet Depth: For deeper shelves or cabinets, thicker lumber may be necessary to support the increased weight and prevent flexing.
In many cases, 1x4 or 1x6 dimensional lumber (actual size: 3/4" x 3 1/2" or 3/4" x 5 1/2", respectively) is suitable for standard shelves with moderate weight loads. For heavier loads or longer spans, 2x4 lumber (actual size: 1 1/2" x 3 1/2") can be used.
However, it's crucial to consider the specific requirements of your project and consult local building codes and standards for guidance. If you're unsure about the appropriate lumber size, it's best to seek advice from an experienced carpenter or consult a structural engineer to ensure the mounting rails will provide adequate support for your shelves or cabinets. Safety should always be a top priority in any construction project.