Taieri-based contractor Ian Brown has avoided a lower section of Three Mile Hill Rd since it was sealed earlier this month, and believes heavy machinery should avoid the road when temperatures rise.
The melted substance can clog electronic sensors and cause nets to tear on his $180,000 bailer and can bind the hydraulics on his $78,000 mower.
But it was his mood which was boiling yesterday morning, after it took three people four hours to clean fine liquefied bitumen and grit from machinery before he could start cutting and bailing hay.
He believes the problem is common on roads in the area, and has become more widespread around Dunedin city and the Taieri in recent years.
"It never used to be like this. I think if you do a job, you should do it once and do it right.
"What I would like to see is more accountability from [Dunedin City Council] or Transit or whoever. It doesn't seem this bad in Central [Otago] or around the Waitaki," he said.
Mr Brown has concerns about seal being laid in cold or wet conditions, and the quality of material used in some roading projects - both of which may contribute to seal melting in hot weather.
Roading projects engineer Evan Matheson said roads on the Taieri and Strath Taieri do tend to have hotter pavement temperature, often reaching more than 50degC.
"This may cause problems of melting but it was not related to contractors cutting corners or defects in road construction.
"It is just more obvious at this time of year, but the problem is no more severe than at any other time in the past."
He did not have concerns about the new surface on a 2.6km section of Three Mile Hill Rd, which was upgraded late last year and resealed earlier this month.
Seal had been "lively" last week, and a maintenance contractor spread chip over the fresh bitumen to address the problem, he said.
Mr Matheson said contractors had used bitumen of consistent quality for the past 20 years, and ensured weather conditions were suitable at the time of sealing.
"There are many factors in seal deteriorating when hot.
"Generally the problem is in the underlying pavement that tends to show through if its been damaged by water, or it happens on an old road that is carrying more traffic and is starting to slowly deteriorate."
