I'd like to install an aluminum 16 x 12 pergola on my existing paver patio and I'm wondering the best way to anchor it.
It comes with brackets to bolt the posts into concrete, with the bolt holes in a square pattern (one bolt hole in each corner of the bracket, 5.7" apart). For each post I'm thinking to use a 12" diameter sonotube with fast setting concrete, set 36" deep ( I'm in NJ ).
I'm not sure whether the top of the concrete column should be level with the ground beneath the pavers, or level with the top of the pavers. I'm leaning towards the top of the concrete being beneath the pavers, so the molding that goes around the bottom of the post sits on the pavers for a clean look, rather than seeing a concrete circle under each post, and challenging myself to not mess up cutting an arc in my paver stones to fit around the concrete column.
If I do this, I'm also thinking to recess the concrete a little below the ground under the pavers to leave some extra space for the concrete bolts that will be sticking up, otherwise those bolts would elevate the paver stones above it to be higher than the rest.
If I do this, can I just put down a layer of sand above the concrete to have a flat surface for the pavers above it?
This is my first time doing something like this, so I'm mainly looking for someone to confirm my plan is sound, or offer any suggestions of a better way.