how far can a 4×10 beam span without support

The span of a 4×10 beam without support depends on several factors, including:

1. Load: The weight and type of load the beam will be carrying (e.g., dead load, live load, snow load).
2. Material: The type of wood used for the beam (e.g., Douglas fir, southern pine, spruce-pine-fir).
3. Grade: The grade of the lumber (e.g., #1, #2, construction grade).
4. Orientation: The beam’s orientation (e.g., horizontal, vertical, sloping).
5. Connection: The type of connections used to attach the beam to other structural elements (e.g., bolts, nails, screws).

That being said, here are some general guidelines for the maximum span of a 4×10 beam without support:

* For a horizontal beam with a uniform load (e.g., a floor joist or a roof rafter):
+ Douglas fir: 12-15 feet (3.6-4.5 meters)
+ Southern pine: 10-13 feet (3-4 meters)
+ Spruce-pine-fir: 9-12 feet (2.7-3.6 meters)
* For a horizontal beam with a point load (e.g., a beam supporting a column or a post):
+ Douglas fir: 8-10 feet (2.4-3 meters)
+ Southern pine: 6-8 feet (1.8-2.4 meters)
+ Spruce-pine-fir: 5-7 feet (1.5-2.1 meters)
* For a vertical beam (e.g., a column or a post):
+ Douglas fir: 10-12 feet (3-3.6 meters)
+ Southern pine: 8-10 feet (2.4-3 meters)
+ Spruce-pine-fir: 7-9 feet (2.1-2.7 meters)

Please note that these are rough estimates and should not be used as a substitute for a professional engineer’s or architect’s calculations. The actual span of a 4×10 beam without support will depend on the specific design requirements and local building codes.

It’s always best to consult with a qualified professional to determine the safe and suitable span for a specific beam in a particular application.