I have a 12' x 16' deck. Construction is 2x10 ledger attached to house and two 2x10 beams sandwiched around three 6x6 posts (posts are set in concrete piers 4' deep). The beams are set in (cantilevered) about 15" from the outside edge of the deck. The joists are 16" on center and are 2x8's. Standard 5/4" decking for the surface.

I'd like to add a pergola to cover the deck and have some design questions about how to intergrate it safely.

Where can I attach the outer posts (those away from the house) to support the pergola? Do they have to be on top of the beams of the deck (which would set them about 15" into the deck surface)? Or, could I attach them to the outside of the 2x8 fascia board with lag bolts? Or, could I set them on the deck surface centered on a joist?

I'm not sure what a pergola would weigh and how that load would be spread on the deck. I figure I could use a ledger on the house to support one side of the pergola and 3 or 4 posts on the outside of the pergola which is the basis for the questions above.

Thanks for any advice.

Augy, you have had 25 reads but no responses. I think we might be able to help if you attach some pics or diagrams/plans.

Here is a picture and a rough drawing (CAD) that depicts the way it's put together. If something isn't clear, let me know. In the CAD drawing the end away from the posts is the ledger (attached to house) and the 5/4" decking boards are not shown.

Anyone?

Replace the corner and center railing post with the pergola post using through bolts. The weight of the pergola will only be the weight of the material itself. If you would like, you could add angle brackets underneath the deck where the deck joist and the band board meet to increase the sheer strength of the band board fasteners.

Replace the corner and center railing post with the pergola post using thru bolts. The weight of the pergola will only be the weight of the material itself. If you would like, you could add angle brackets underneath the deck where the deck joist and the band board meet to increase the sheer strength of the band board fasteners.

Thanks for the reply. I was hoping I would be able to utilize the railing posts as you suggest. I had considered using 4 of them to create 3 "window" areas for either lattice or blinds.

Thanks again, I'll plan to shore up the band board to joists with some angle brackets just to add some extra strength.

I just covered a deck like yours w/ a hip roof w/a raised secondary roof to allow air to escape it turned out beautiful lots of shade and lower electric bill I will now paint and install 2 ceiling fans good luck art

Augy, I am curious if you got your pergola completed... If so, could you post some pics? I am considering the same project.

Thanks,
DP

I'm not sure if I would just replace the end posts for the pergola support. They are just lagged into the side. Personally I would want the pergola posts centered directly over a joist. This way the load continues directly through the structure and into the concrete.

I'm considering the same project, however, my deck is 16x12 and is approximately 18" from the ground.

Ideas.