pergola posts

[Bope]

I am planning on putting in a paver patio and pergola. My plan is to use sonotubes for the footing of the posts then use a post base with pressure treated 4x4 post. The 4x4s will then be faced with 1x cedar for looks. My question is about the paver, concrete, post interface. I was thinking of bringing the paver over the concrete footer up next to the post. Do I put the top of the footer even with the ground so the paver base goes over the footer essentially sinking the post in the ground the depth of the paver base? Or set the footer even with the paver base so just the pave sits on top of the footer next to the post base? I am wondering if I am using a post base with a standoff to keep the post off the concrete and keep the end of the post dry am I negating all that by sinking the post in the paver or the paver base? Should I use a bolt long enough to reach up through the pave base to the top of the paver and set the post base on top of the paver? I can always run the ceder close to the bottom of the post to hide the post base. I was trying not to just sink the 4x4s in the ground in case they needed repair in the future. Any suggestions would be appreciated.

[crokett™]

if it were me, I'd pour the footing and set a j-bolt long enough to get through a paver, then drill a hole in a paver and set the post base on top of the paver, but only if the paver is structurally rated and/or is supported well enough to be. Otherwise, it is likely to crack. I'd do this because it keeps the post up away from the ground. I might even pour the footing and set a paver in the wet concrete on top of the footing. That way I know it's supported.

[Splinter Puller]

I would probably transition the sonotube shape to a square matching the finished post shape at the top.  This will require expert layout and you should use rebar in the concrete to keep the top shape from breaking loose from the bottom round shape.  I'd probably pour the top shapes seperate from the bottom so as to get them all aligned properly.  There would be a cold joint but so be it.

[TDKPE]

I would probably transition the sonotube shape to a square matching the finished post shape at the top.  This will require expert layout and you should use rebar in the concrete to keep the top shape from breaking loose from the bottom round shape.  I'd probably pour the top shapes seperate from the bottom so as to get them all aligned properly.  There would be a cold joint but so be it.

Our tower crane starter feet are installed using high-strength, non-shrink grout to fill the space between the concrete foundation and the bottom of the feet (to allow leveling/co-planer adjustment of the top surfaces).  Perhaps something along those lines would work.  Grout in bags from the BORGs show 14,000 psi compressive strength, which is many times higher than the concrete strength anyone is likely to use in Sonotubes, and of course, there's relatively little pressure on the bottom of a pergola column. 

But it would allow for less precise Sonotube installation and concrete placement, and maybe the pavers could be installed using grout at the footings.  Or a hole in the pavers for grout.  Or something like that.

[blackhat]

What size sonotube?  I'd use 6" and bring the top of the tube to finished paver height. If you are cladding the posts, add a second trim wrap at the bottom and you won't see the concrete. Alternatively, get some dye powder and colour the top few inches of each pour to near match the paver colour.

[LarryK]

Is the pergola attached to the house? If not four posts on metal post bases will have no lateral stability. Also don't put pavers on the concrete bases youll get differential movement. Pergolas really don't have any weight to them so sinking a treated 4x4 and pouring concrete around it is an easy thing and more than adequate. I do this often and then wrap them in cedar. If you're worried about post rot coat the sides and bottoms of the posts in an asphalt foundation coating. I do that too when I have to sink a cedar post 4x4 or 6x6. I've done some 10 years ago no problems.