Waikato District Council managed to secure sufficient additional funding needed to replace instead of demolishing it.
The power lines overhead also meant getting rid of the old roof and installing the new one was more complicated than usual.
Transpower supported the project by carrying out extended power outages to allow work to be undertaken.
It also provided a grant to offset costs related to working around the power lines.
The new grandstand roof has been strengthened with fabricated steel beams and protection from the weather has been improved with new, stronger roofing iron, flashings and gutters to the modern building standards.
"Replacing a roof might sound simple but the power lines above the grandstand really made this job tricky," said Waikato District Council project manager Trevor Ranga.
"But the excellent collaboration between all the parties involved was a major factor in the successful completion of this project.
"Transpower, Industrial Site Services, Hamilton Blast and Paint, Watertight Construction, and Action Bobcats all played key roles in ensuring that the grandstand now has a fantastic new roof."