porch roof beam size

[jhivy]

I will have a span of about ten feet between posts, and am trying to calculate an appropriate sized beam to support the rafters without sagging in the middle.  I have had little luck finding an online calculator for this application.

The shed roof will be 8 ft X 32 ft, framed with 2X6 rafters, 24 in on center.  Metal roof.  3/12 pitch.  In Mississippi, so snow load is not an issue.

The beam will be built as a 2x dimension lumber sandwich with a plywood center.  I found a guideline online that stated 1 in width 2x for every 1 ft of span.  A header that tall (10") when mounted on the posts would not be visually appealing.  Not to mention taking up a lot of headroom over the entry.

I would like to use 2x8s for the beam.  Any of you diy engineers out there think that's too small?

[jhivy]

Sorry guys.  I just saw the link to multiple beam calculators in our very own forum in the referral links section.  Why was I wasting my time with google?  The Medeek Toolbox beam calculator spits out more info than I can understand but got the OK in bending, shear, deflection and bearing for a beam of that size.  Great tool.  Thanks Medeek!

[Don_P]

It passes for me. Do make sure the posts align with any porch posts below. Best practice on things like this is to frame porch posts no more than 8' on center, then built up girders can be made of 16' material with the joints breaking on alternate posts, weaving the beams into a long continuous member.