Need to attach 6x6x8 posts for a free-standing pergola - I'll use Strong-Tie anchors attached to the concrete footing.
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The hole for the footing will reach well below the freezing line, but how wide should it be?
EDIT
Found these construction guidelines for decks that recommend 14" diameter holes, but not sure if there are other recommendations for pergolas.
Since it is a structure that is not occupied in any way, I believe there are no codes that would govern footings for pergolas.
With that said, in my opinion, any hole worth digging for concrete should be at least 12"X12" or 12" round. Just to make a point, the posts could simply be set in the ground, using the 6X6 bottom as the bearing surface. Even not knowing your soil type, or bearing capacity. I am sure that would hold anything that may grow upon your pergola, BUT you have the right idea about the concrete. With the concrete poured a little above grade and the post clip added to the bottom of the posts, you have a good set up for long lasting posts.
The biggest thing will be is, you will need to provide bracing so the pergola does not rack.
