Building a pergola and cement patio
Hi All! I've been reading posts on here for the last 3 or 4 months - it's been a great help, but need some additional advice. We are building a cement patio and pergola simultaneously. The dimensions for the pergola are 14' x 18' OC. We'll use 6x6 posts, 4x6x18 rafters, and 4x12x20 support beems (shorter than we would have liked, but already purchased wood), notched to posts. We're using western red cedar (heartwood) w/ 4 knee braces and it will be about 8-9' tall. We have decided to put the posts in the ground in concrete w/ a 6" rock base - I know this is a big area of debate, but I don't think we have another option. I'm concerned that if we use the metal post anchors that go in to cement, we wouldn't be able to get it exactly square - if we mess up we're screwed. I don't think the anchors that go on top of concrete would be enough to prevent racking on such a long span pergola. So, we're back to posts in the ground w/ concrete. We've already prepped the patio area, now we're ready to put the posts in the ground. The posts will be 2 ft deep. After the posts set, we'll add 2 inches of subbase, then pour the 4 inches of cement. So the posts will be a total of about 2.5 ft down (we're in Alabama so no real frost threat). Is this the correct way to go about doing the posts and patio at the same time? Does anyone see flaws in the plan? We've done 90% of our research online - any help/comments would be appreciated.