Beam Construction

http://www.hammerzone.com/archives/framecarp/repair/porch/beam13/replace.htm

Our old house had a problem with the roof structure on one of the porches. A previous owner had replaced the load bearing beam with a smaller piece of wood, and the roof was sagging by about 1½" in the middle of the beam span. Besides being too small, their replacement beam didn't even come close to matching the architectural detail found on the other porches.
So in the midst of re-shingling that porch roof, we decided to spend a couple of days fixing the structure. This repair involved:
Supporting the weight of the roof.
Removing the old beam.
Repairing rotted framing members.
Installing a new beam made of four pieces of lumber.
Replacing the wood trim.


http://www.ilevel.com/roofs/r_ParallamPSL_beams.aspx