Two 2x6's will be stronger than a 4x6.
How do you figure?
When I frame custom houses, often solid beams are called out for window headers VS doubling or tripling dimensional lumber. Engineers never let us substitute.
Really? I always thought that two boards with different grain patterns complimented each other and made for a stronger beam.
Engineers ought to know, which I'm not.
And, certainly, not all 2x6s or 4x6s are equal either. Classes and grades of lumber can be very, very different. Engineers and architects can be very specific, and for good reason. A piece of clear, straight douglas fir, for instance, is typically much sturdier material than is the same size material of common pine or spruce. There's a reason why a 99 cent 'white-wood' stud is called "economy" while a 'select' stud might run $3.49 per.
