Design review board reviews Borden Farm Estates plan: 20 units, historic preservation, StormTech drainage and septic discussed

The Portsmouth Design Review Board reviewed a detailed site plan for Borden Farm Estates, a proposal that would conserve the existing historic farmhouse and barn while adding new residential buildings behind those structures. Garrett DeCastro, the owner and applicant, told the board the plan calls for 16 new units and four renovated units in the existing barn for a total of 20 units, and that 25 percent of the units would be offered as affordable housing under state requirements.

At a high level, DeCastro said the design places new buildings behind the existing farmhouse and barn to preserve the East Main Road-facing historic appearance: "We're proposing what would be the new Borden Farm Estates, which would just be an extension of the community while preserving the history of the estate itself," he said. He described keeping the farmhouse and barn architecture, renovating the barn into two-bedroom townhome-style units and adding complementary materials for new construction, including hardy board and architectural asphalt shingles.

Board members and the applicant focused on circulation, fire access and grading. The applicant and engineer Tom Principe (Principe Engineering) said the design provides a two-way loop sized for fire apparatus and includes two proposed hydrants. Principe explained the site’s stormwater solution: "we're using underground storm tech infiltration units ... and then it's gonna be grass and lawn, so it could be used as recreational area ... we had to comply with the DEM standards with the groundwater table. So that's why they're elevated." He said the StormTech systems and an infiltration basin mitigate roof and surface runoff and that the seasonal high groundwater required the systems to be raised above the groundwater table.

The board discussed a retaining wall that the team proposed to preserve a significant maple tree; the applicant said the wall is landscape-scale (about 2.5 feet at its maximum point) and was included to protect the existing tree. The board urged the applicant to consider grading alternatives that would avoid a wall if possible and to design the wall with landscaping to soften its appearance.

On utilities, Principe said the project must use three private septic sand-filter systems because sewer is not available; the team located two sand filters in the front to serve the existing and nearby buildings and a third toward the rear to serve other new units. Board members asked the applicant to landscape around septic infrastructure so it is less visible from the road.

Board members and the applicant discussed plantings, irrigation and survivability. The applicant said the town-required screening along the east perimeter would be a single row of trees plus a cedar-on-steel fence and that a "mini barn" on the site would be relocated to create a mailbox station and screen dumpsters. The applicant agreed to refine planting spacing, select species less vulnerable to deer browsing and consider temporary irrigation or drip systems to reduce early mortality. On lighting, the applicant said all fixtures would be building-mounted, dark-sky compliant gooseneck-style fixtures; the board discussed providing conduit sleeves for future upgrades to solar lighting along walkways.

The board also discussed lot layout and site aesthetics: members suggested sidewalk connections to East Main Road, parking islands or additional landscape islands to break up parking rows, and low hedges to screen front-row cars from the street. Garrett DeCastro said the units would be sold as condominiums under a condo association, not rented, and emphasized prior contact with neighbors and town stakeholders during design.

No formal approval or final vote appears in the transcript. The applicant said the project has been to the planning board and that the main outstanding item was a physical alteration permit; the team said it would provide the board with refined planting, lighting and wall details and confirm final hydrant locations and septic designs with the relevant town departments.

Key specifics recorded in the meeting: 20 total units (16 new, 4 renovated in the barn); three private septic sand-filter systems; two proposed hydrants; StormTech underground infiltration units with a raised infiltration basin because of a high seasonal water table; preservation of the existing farmhouse and barn, with the barn remaining wood-shingled and the farmhouse listed on the local historic registry, according to board discussion; 25 percent of units to be affordable for sale per state requirements.

The board asked the applicant to return with final landscaping plans that include plant species and spacing, screened and softened septic/sand-filter areas, sidewalk connections to East Main Road and details for the proposed retaining wall and mailbox station.