My customer just bought a used 953 Cat loader. Came as an open top with no rops. He wanted something to keep the rain off as well as any errant tree limbs etc. He picks & sells stone to the supply yards. It's not meant to replace the rops but just some protection mainly from the weather.

Main hoop is 3x3 tube & the rest is 2x2 tube with 1/8" sheet on top. All open tube ends were capped. I determined the height by measureing two other machines with cabs & they were about 5' 2" from the floor to inside of the roof. The roof overall is about 5' square. There were already pads on the machine to bolt it to so I just had to retap the holes as they had not been used in a long time. Painted with spray cans because if I didn't the owner most likely never would have.