I’m trying to build a deck gate at top of stairs. Problem is I have to offset 6×6 posts.
What should I do, Should I just add another 6×6 post in the nearest post to make it even?
Best Answer
I believe that you are over thinking the need to have the gate be somehow "even". You should just hinge the gate at the post that is on the side nearest the street. Then just simply arrange the gate to swing up against the deck side of the closer post. The diagram below shows how it is done. The typical hinge usage for this type of application is also shown.
As you can see from the above diagram the gate ends up being "even" (parallel) with the deck boards.
To accomplish the join I'd acquire some 1/4" by 3-1/2" by 24" steel plates and let them into opposing sides of the posts to act as gussets. I'd use countersunk flat-head sleeve bolts, piloted accurately and minimally, to sandwich the whole works.
Be sure to consider whether the existing posts are adequately anchored, as there will be substantial torque applied to them at their bases. It doesn't matter how well you attach the extensions to floppy posts.
That said, I think your plan seems flawed. A pergola creates some fairly unique structural concerns, namely the lack of diagonal bracing that a conventional roof would provide, as well as increased wind drag.
I'd be replacing your 4x4 posts with 6x6 posts that run all the way through. They'll do the job much better than spliced 4x4s, and they'll probably be more appropriate from an aesthetic standpoint, depending on your design. You don't want chicken legs under your nice new pergola.
If you elect not to do that, consider substantial diagonal bracing below the ceiling line connecting the posts to the primary horizontal members of your design in appropriate directions (where connection to a fixed structure doesn't provide support).
Best Answer
I believe that you are over thinking the need to have the gate be somehow "even". You should just hinge the gate at the post that is on the side nearest the street. Then just simply arrange the gate to swing up against the deck side of the closer post. The diagram below shows how it is done. The typical hinge usage for this type of application is also shown.
As you can see from the above diagram the gate ends up being "even" (parallel) with the deck boards.