simple diy pergola plans - construct101 diy pergola plans – assembly. measure a 10’x10′ area making sure it is squared by measuring diagonally in both directions. use 12′ long 6×6 poles (a) with 2′ in the ground with concrete as shown in illustration above. if you are using anchors on the poles use 10′ 6×6 poles. use a level to make sure all the poles are leveled.