I am building a gazebo. My backyard has a fairly steep elevation and therefore my foundation will be 12 inch diameter concrete piers, using quick form tubes. My question is, when I dig my hole (42" deep per my village) do I dig a straight hole and fill the bottom with gravel and then pour the cement, or must I pour a foundation of concrete that is wider than the 12" quick form tube? Is this necessary to support the gazebo?
The gazebo is a 12 foot octagon and I live in the midwest. Another question, since my yard is not level I must level the concrete piers to support the floor of the gazebo evenly. What is the best way to precisely level the height of the concrete piers, since they will be at least 12 feet apart (front to back)?