What size beam should I use for the roof of a 10x12 shed? 2x8 or 2x6?

Question

The beam will be spanning the 12 foot section. What do you think would be the best one to use?

Answer 1

Is this for the ridge board?  If so, the next question is do you plan on having ceiling joists or collar ties.  If so the ridge can be smaller.  There is a difference between a ridge beam and ridge board.  A board is just a nailer for the rafters and doesn't carry the load the roof.  The load is carried by the rafters and transferred to walls.  If you don't use ceiling joists or collar ties then it means it is a ridge beam and carries part of the roof load.  It also means you need to have a king post to transfer the load from the ridge beam down to the foundation.  So the beam carries the half of the roof, the walls carry the other half.

If you are using the ceiling joists or collar ties, determine the size of the rafters, and go up one size.  If you use 2x6 rafters use 2x8 ridge board.  It isn't to carry the load, but when you cut the plumb cut on the rafter, the length of the cut will be longer than 5 1/2", hope that makes sense, so if you use a 2x6 ridge part of the rafter won't be sitting on the ridge.

Answer 2

2 by 6 is lots.

Answer 3

When in doubt always go with the stronger (2X8).  you can't have it to strong, but you can have it to weak.  Do you have a lot of snow in your area ?  Snow weighs allot.