"With demand, it's just growing and growing," James said.
"There are times when we are working on a site and someone two houses down says 'Oh, I didn't know there was another company in town, can you come and do a quote for my place?'"
The company now covers scaffolding, safety nets and edge protection and can tackle up to six houses at any one time.
As well as construction companies, Barred Up works with painters, glaziers, homeowners, gutter cleaners, and recently provided scaffolding for Q-West Boat Builders.
James has a background in electrical engineering and electronics, while Robbie is a qualified builder and constable with the Whanganui Police.
Robbie said he was surprised how fast the company had taken off, and he didn't expect things to slow down any time soon.
Until now they had run almost entirely on "word-of-mouth".
"There is work piling up in the construction industry in Whanganui, you only have to drive down the Fitzherbert Ave extension to see that. A lot of people still want to move here.
"I think we (the city) can handle it, though."
Palmerston North-based company Scafit also operates in Whanganui.
JD Builders owner Jack Williams said his current workload was very heavy, so it was great to have another local scaffolding option.
'We've used Barred Up on a couple of house projects recently," Williams said.
"They are reliable and eager to meet the client's needs."
Barred Up now has a team of seven.
"For both of us, we've got other full-time commitments," James Dickson said.
He said the pair had to learn about employing people, but as the workload increased so did their need for more staff.
"At the moment we are keeping things under five metres. Once it gets above that you move from basic scaffolding into intermediate and advanced.
"We are currently in the process of getting those qualifications."
Decorator Kevin Tozer said Barred Up had been onboard for a number of his company's jobs.
"I've been really pleased with their workmanship and attitude throughout the contracts.
"Scaffolding is always difficult to get because it's in high demand these days, but they've been helpful and obliging."
While Barred Up had the ability to do jobs out of town, the company's main focus was giving the best service it could to Whanganui, Robbie Dickson said.
"We are going to run a couple of guys through apprenticeships, and James will be doing one as well.
"It's been an interesting journey so far. Definitely stressful, but lots of fun as well."