"We think that any reasonable person, whether having an educated planning eye or not, would call it an industrial/commercial area," the decision said.
"This area has become a de facto industrial/commercial node and there is no point pretending otherwise."
A series of consent decisions meant "the horse has bolted and the best that can be done is to stop the de facto node spreading outwards".
Mr Roil's land was close to the centre of industry in the area, so would not extend it.
He would use the site for his prefabricated building business (formerly Cottages NZ) as well as a trades training facility in partnership with EIT.
Hastings Mayor Lawrence Yule said the council would not appeal the decision but would continue to protect the plains zone while facilitating commercial/industrial precincts.
"The very balance of what is growing our economy is what we are growing on the good fertile soil - that's where most of the grunt is coming from," he said.
In 2012 Mr Roil was fined for breaching the Building Act for constructing a building without a consent and, with neighbouring landowners, is currently in a dispute with the council over the cost for infrastructure services to the Irongate industrial area.