SOUTH DEERFIELD — An extensive addition to Hamshaw Lumber’s South Deerfield location can move forward following the Planning Board’s site plan review and stormwater permit approval this week.

The New England hardware store is seeking to construct a new 12,245-square-foot building at 14 Elm St., adjacent to its existing building at 16 Elm St. The new lumber storage and sales warehouse space will go on land Deerfield swapped with the company, which allowed the town to go through with its extensive Leary Lot project.

“Generally the site plan for this project is pretty simple,” said Jeff Squire, a landscape architect and principal of Berkshire Design Group, who also worked on the Leary Lot with the town. Along with the extended store space, Hamshaw Lumber is also going to add new spaces to the front of its building, extend its gravel parking lot and connect a rear sidewalk to what will be the public sidewalk of the Leary Lot.

Ken Hamshaw, president of Hamshaw Lumber, said business at the front of the store will remain largely the same, as “cash-and-carry purchases” will be done in the front, while larger purchases can be loaded into people’s vehicles behind the building.

The new building, said architect Erica Rioux Gees, will be designed to fit in with Hamshaw Lumber’s other locations and will conform to other designs located in South Deerfield, as the building is a “gateway project” that greets drivers as they turn off Routes 5 and 10.

“It will completely fit in with the scale of the town center,” Rioux Gees said, adding that the building will “follow that same vocabulary and use the same materials, the same trim details,” as the company’s other stores.

Planning Board questions on the site plan were limited, although there was a brief discussion on the stormwater permit and if the board should pursue a peer review of the proposed system.

The company is proposing three drainage areas that will take water from the proposed building’s roof, part of the existing roof, and the surrounding area of 14 and 16 Elm St., which will all flow directly into the existing Elm Street drainage system.

“It is a 12,000-square-foot addition, there is a lot of water,” said member Rachel Blain. “I feel like it’s very well presented and I know they’ll be good neighbors, but it is a big project.”

Building Commissioner Robert Walden and Planning Board Chair Denise Mason said the proposed system will be effective, especially given that Berkshire Design Group worked on the Leary Lot.

“I didn’t think it was that complicated,” Walden said. “And seeing as how Berkshire Design did the Leary Lot and seems to be thinking of the two of them together … I have confidence in them, but ultimately it’s your decision.”

Squire added that the town abuts Hamshaw Lumber on three sides of the property and Berkshire Brewing Co. is the abutter on the north end, and they “feel comfortable in the system that we designed to accommodate that runoff.”

“We’re certainly capturing everything and then some,” Squire said. “It’s pretty robust in terms of how much water we’re capturing.”

The Planning Board opted to not have a peer review conducted and unanimously approved the site plan review and stormwater permit.

Chris Larabee can be reached at clarabee@recorder.com.