how far can a 2×12 span

The maximum span for a 2×12 beam depends on several factors, including:

1. Load: The weight and type of load the beam will be supporting (e.g., roof, floor, wall).
2. Species and grade of lumber: Different types of wood have varying strength and stiffness properties.
3. Orientation: Whether the beam is installed horizontally (e.g., as a floor joist) or vertically (e.g., as a column).
4. Support conditions: Whether the beam is simply supported (e.g., resting on two ends) or has intermediate supports.

Here are some general guidelines for maximum spans for 2×12 beams:

Floor Joists:

• For a residential floor with a live load of 40 pounds per square foot (psf) and a dead load of 10 psf, a 2×12 beam can span:

  • Up to 16 feet for a simple span (e.g., a single room).
  • Up to 20 feet for a continuous span (e.g., multiple rooms).

• For a commercial floor with a live load of 50 psf and a dead load of 15 psf, a 2×12 beam can span:

  • Up to 14 feet for a simple span.
  • Up to 18 feet for a continuous span.

Roof Rafters:

• For a residential roof with a live load of 20 psf and a dead load of 10 psf, a 2×12 beam can span:

  • Up to 20 feet for a simple span.
  • Up to 24 feet for a continuous span.

• For a commercial roof with a live load of 30 psf and a dead load of 15 psf, a 2×12 beam can span:

  • Up to 18 feet for a simple span.
  • Up to 22 feet for a continuous span.

Headers:

• For a residential header with a load of 40 psf, a 2×12 beam can span:

  • Up to 12 feet for a simple span.
  • Up to 16 feet for a continuous span.

• For a commercial header with a load of 50 psf, a 2×12 beam can span:

  • Up to 10 feet for a simple span.
  • Up to 14 feet for a continuous span.

Please note that these are general guidelines and may not apply to your specific situation. It’s always best to consult with a structural engineer or a qualified building professional to determine the maximum span for a 2×12 beam in your particular project.