I am working out the details for building a four column hip roof gazebo. I have gotten some advice here and there and thought I would post here as well. I am looking to build a 10 x 12 open air gazebo using the fiberglass/composite columns that HD and Lowes sells.

I am hoping to make it look something like this.

My concern is the stability of the columns holding up all that weight. They are rated very high but it seems it would be prone to sway and collapse in high winds which we have here at times.

This is what I am thinking for my stability. A 4ft hole and 1ft high footing and 8ft lally. This would give me 5ft of lally column in a 7ft column. Comments appreciated.