Need help with question on base for interlocking and pergola
1) since the area is quite large, where can we buy reasonable price and quality geotextile and HPB. I heard it that it is cheaper at aggregate yards than garden centers or landscaping places..
2) we are thinking to build 6 inches base. Is this sufficient for walkways and patio?
3) can we make 3 inches of granular A crushed stone and 3 inches of HPB as we heard that HPB is more expensive? Or we have to build 6 inches of HPB
4) Also we want to a pergola as well on the interlock patio. The size is 16Wx16Lx12H ft we are thinking. How many posts do we need. Do we have to pour concrete for the base and how thick is needed?