Second floor beam spacing?

[wannabuildacabin]

  ???Im going to use 4x10x16' exposed beams for my second floor covered by 2x6 t&g.  How far apart should I space the 4x10's?

[Redoverfarm]

Some have gone as far as 48".  On mine I went 32" in a 16'span with 4X8's. 

[Don_P]

2.66' (32")x16'=42.56 square feet
42.56x 40 lbs per sq ft = 1702.4 lbs
If this is #1 or #2 Eastern white pine it fails at that spacing.
At 24" it passes in #1...which if you pick tags a Turmans you will find, in #2 it just fails at the full 16'... I'll bet the clear span is under 16'. Do clear this all with the inspector before you do it. I'd be happy to check more options if you need.

If this is homemade I'll have an engineer over at my place in the next week or two grading beams.

[SkagitDrifter]

I used 5-1/8 x 12 GluLam Beams and went 48" on center, the span for the GLBs is 20 feet.
The 2x6 T&G is Spruce and spans about 43".  No noticable deflection in the floor at all.

[Don_P]

Probably too much information but we're comparing apples to oranges there.
a 4x10 has a moment of inertia of 230.8 "^4
a 5-1/8x12 has a moment of inertia of 494.4"^4
The species and grade of a glulam, is also generally much higher than solid sawn.

[wannabuildacabin]

As far as wood species goes, how does the southern yellow pine compare to the white pine? I found #1 grade in the yellow pine. And thanks for all the input so far.

[Don_P]

Whoops, sorry I missed this.
#1 4x10x16' syp barely blows out in deflection at 15'1" span (I'm assuming you have 16' outside dimensions) at a 4' spacing. So 4' is just a little too much, if you can sneak down to around 42" it would work fine.

So in a roundabout way we just answered a question, southern yellow pine is roughly twice the timber of eastern white pine  .

[wannabuildacabin]

  Thanks Don. Sorry for all the questions just trying to get all my ducks in a row.