Expert: Dave Johnson - 6/4/2007

Question
I have a few questions about building a pergola.  I have emailed before but have now changed the plans.  I have an odd shaped patio (pavers) and I can only place posts in certain locations.  Here is what I would like to do..

Number's 1 to 5 are the posts.
Letter L is the ledger board on the house.

    1                  2





    3                  4                  5



LLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL


There is:
18' between: posts 1 and 2
            posts 3 and 4
            posts 4 and 5
10' between: posts 1 and 3
            posts 2 and 4
6' between posts 3,4,5 and the ledger board (L).

I am planing to have 3 beams.  They will run from posts 1 to 2, 3 to 4, and 4 to 5.
The posts will be hot dipped in cement.  The beams will be on top of the posts.
Each beam will be two 2 by Xs? bolted together.
Posts 1,2,3,5 will be 4x4s.  Post 4 will be a 4x6 (I would like it a little wider since the two beams meet on the top of it.  3" of each beam will rest on top of this post).

There will be two different lengths for the rafters:
Half of them will be 18' long.  These will be attached to the ledger board and run over the beams that are on top of posts 1-2 and posts 3-4 (There will be a 2' overhang here).
The other half of the rafters will be 7' long and will be attached to the ledger board and run over the beams that are on top of posts 4-5 (There will be a 1' overhang here).

Questions:
What size rafters should I use?
Should the rafters slant slightly from the house or should they be level?
What size beams should I use?
What size ledger board should I use?
How should the rafters be attached to the ledger board? Can joist hangers be used for this?
Is 4x4 sufficient size for the posts?
Not sure what kind of wood I should using.. Is there pressure treated posts? beams?

rafters?  Should I be applying stain to them myself?

Any help appreciated.

Answer
Hi Rich, I like your details! Nice way to get around sending a plan.
Anyway, if aesthetics aren't an issue, go with pressure treated and joist hangers.
Rafters: Your longest span is only 10' with no load, so 2"x8" is fine
I would pitch the rafters just slightly so that moisture laying on them will run away from the building.
Beams should be (3) 2"x8" laminated.
Ledger is okay at 2"x8".
Posts: your idea will work.
Again, pressure treated is good, but isn't as appealing as
cedar or a stained wood.

Dave