Expert: Bruce E. Johnson - 6/3/2011

Question
I have a patio that I would like to cover with a pergola.  Where I can dig holes for the 4 corners,  the dimensions would be 10x16.  This would be free standing behind my home(not attached to the home).  I'm planning to have the long side facing away from the home to view the yard and wild life that comes onto our property.  I would like to have only 4 posts so as not to block the view.  I can only get treated lumber in 16' lengths.  Any idea on how I can make the 16' length(really about 18' when you add a foot on each end for a decorative look) and would it sag a lot over the years?  I could cut diagonal supports that would go from the post to the beams.  What do you recommend?

Answer
Hi Greg yes you can build a beam by starting off with a four foot piece and then a full length piece and then put a full length board and a four footer on the other side so that your joints are at opposite ends of the beam.  By putting the shorter pieces at the ends  it leaves the middle stronger and less likely to sag. I hope is information helps please feel free to write again regarding this or other matters, sincerely Bruce Johnson