"It's not just one category, it's the whole shebang. If you're a builder, you want that craftsmanship."
Mr Riordan put his success down to the team, including wife Helen Riordan, who helped transform the old brick and tile colonial home into an elegant, classic four-bedroom property commanding 180-degree views of Tauranga Harbour.
"The most important thing is the team thing. If you surround yourself by good tradespeople, you are going to get the award in the end."
He added that his client's personal touch on the finishings and decor deserved as much credit.
"It's very easy to build a great place but you don't [complete it] if you don't have all the furnishings to make it look great."
Mr Riordan said the renovation offered a chance to work closely with architect Fraser Cameron to come up with a satisfying result.
The homeowners, who asked not to be identified, said they were "delighted" with their home and Riordan Construction's wins.
The house had been in the family for 25 years and had many personal memories to it, which Riordan Construction was able to incorporate into the build, the man of the house said.
An old block of stones, with rocks collected by family members years ago, was re-modelled into an inviting stone wall at the home's impressive entrance.
"I thought it was going to be fantastic but it's better than I thought. You always look for disappointment like 'what should we have done differently?' but I can't actually think of what we would have done," he said.
The only things remaining from the original house are the concrete slab, fireplace, stairs and roof.
The woman of the house said the house was a "colonial clunk of brick" before but was now classically understated and inviting.
Judges at the awards said Riordan Construction gave the home a new lease of life.
"The interior has been skilfully renewed, particularly the kitchen and bathrooms which are a credit to his detailed craftsmanship.
"The ability of the builder to meet the owner's requirements so well is a testament to his dedication and commitment to the job."
The national PlaceMakers Supreme Awards for Renovation of the Year and House of the Year, will be announced in Auckland in November.