I'm considering using a 6x6 beam to span approximately 15 feet by 9 feet without any support in the middle. Is this a feasible option, or should I go for something else? I want to clarify if the 6x6 can handle that span on its own.
3 Answers
Generally, the rule of thumb is that the depth of wood should be span/2 + 2, which would suggest a minimum depth of about 9.5" for a 15' span. A 6" beam won't cut it here, especially if it's unsupported. Why not use 2x10s instead? They provide better strength due to their design.
If there's no load, the 6x6 might hold but expect it to sag a bit under its own weight. I’ve done something similar with 4x4s, but my beams bent a little before I switched to 4x8s with steel brackets. No more bending issues since!
Using a 6x6 for that span is not ideal. A beam that long will sag quite a bit over time due to its weight. Instead of a 6x6, you might want to look into double 2x10s. They provide better support without the sag issue.
Exactly! A double 2x10 setup would give you about 15' of strong support. Plus, they're lighter than a 6x6, so you won't have to worry as much about bending.
I went for the square beams for looks, but now I see that's not the best way for structure. You definitely want depth for strength.