Expert: Bruce E. Johnson - 1/30/2009

Question
We are putting in a support beam in an old farm house,to support the 2nd floor.  The span is 19 ft. The beam is 10" x 12" X 21'(hemlock). 2' extend into a closet on one end, the other end is supported by the first floor wall.  The room size is 19' X 30',the beam runs through the center.  Will we need any other support in the 19' area so the beam does not sag, or can it be left open?

Answer
Hi DeAnne, that is a pretty hefty beam.  I think it should work.  A 4x12 will span up to 14' for this kind of application so a 10x12 should be able to span 19 feet.   It might have a slight bounce to it but if it is installed properly with the crown up (every beam has a high side to it this is the crown by putting the crown up you counteract the effects of gravity as it tries to flatten the beam out over time) it should be okay. check out this link :

http://www.awc.org/technical/spantables/tutorial.htm

It gives a good explanation of beam spans etc.

I hope this information helps.  Feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com