LOCKPORT – Mantelli Trailer Sales plans to mark its 50th year in business this year with a $1.5 million expansion.

Mark and Kim Watson, owners of the recreational vehicle dealership, Thursday presented their request for a property tax abatement on the new building to the Town of Lockport Industrial Development Agency.

Town Economic Development Director David R. Kinyon said a cost-benefit analysis will be done and, at next month’s meeting, the IDA board will consider scheduling a public hearing on the request.

Kinyon said the application envisions the creation of three new jobs. IDA board member Duncan N. Carlson said he’d like to see some sales tax data from the business, too.

“We have to justify why we’re giving them $135,000 [in tax breaks] over 10 years,” Carlson said.

Kim Watson, the daughter of the business’ founders, Al and Shirley Mantelli, said the company acquired the lot next door last year and plans to use it for a larger store, south of their current location on South Transit Road. “We’re pretty well packed in there,” she said.

Mark Watson said they are still considering several building sizes and styles, and they are awaiting cost estimates for each. No materials have yet been submitted to the town Planning Board, which also would have to approve them.

Kinyon said, “They’re in tune with Transit North design concepts,” referring to the town’s notion of a historic-looking gateway along Route 78.

“That area needs a lot of improvement,” Carlson said.

“They’re going to design and build a nice building. It’s a once-in-a-lifetime project for them,” Kinyon said.

Mark Watson said the three existing buildings would be demolished and replaced by the single new one.

Kim Watson said the project would be phased, to minimize disruption to the business. She said the new building would shield the company’s storage buildings from the view of motorists along South Transit Road. “Storage is a big profit center for us,” she said.