Robert Mills Residential Award > Residential New Construction under $1,000,000
Wild Marsh dogtrot
St. Helena Island, SC
This contemporary interpretation of a dogtrot gets a head start in sustainability by incorporating vernacular passive strategies while creating a modern regionalism. The vernacular dogtrot form takes advantage of increased wind at building corners by having two buildings connected by a porch. The buildings are oriented to funnel the prevailing breezes through the central porch. The 700 s.f. main house and 285 s.f. guest room lives much larger with the addition of the 530 s.f. porch. The house is designed to be net zero when the solar panels are installed
The clients wanted to downside in their retirement and be connected to the land. The rural site is on the edge of a tidal creek one island back from the Atlantic Ocean. The dogtrot is a vernacular building form that was created from necessity. The coastal South’s harsh, hot, humid, flood and hurricane prone conditions demanded buildings whose form responded to prevailing breezes, sun angles, vegetation and water. The open porch between the two masses of the dogtrot captures the prevailing breezes off the water which are funneled through the dogtrot porch.

The house is sited and designed to maximize daylight and natural ventilation with the dogtrot. In a hot humid climate thin, light weight walls are essential to minimize thermal mass and allow for cooling. The large overhang and porches reduce solar gain. In temperate weather, the house can be opened to take advantage of the prevailing breezes. Detailing a tight building envelope reduces energy usage.

The house is photovoltaic panel ready for future installation.

The clients program included a 3000 s.f. single family house and a small cottage guesthouse on a six acre site. They wanted to build the cottage first and live in it while the mainhouse was designed and built. Once the cottage was built, the clients decided that small living is for them and are not going to build the bigger house.

In a note from the client, she said, “And that dogtrot porch – I am sitting out here now and the breeze is phenomenal – it’s the best napping spot in the house.”

Design for Integration & Ecosystem

The project is located on an erosion remnant island which is inland from the ocean. Erosion remnant islands are much more stable than barrier islands but still play an important role in protecting the mainland from hurricanes.

The small lot has natural undisturbed buffers on three sides and a reconstituted buffer on the river. The 50 foot river buffer helps to prevent erosion, abates flood and storm damage, provides wildlife habitat and improves aesthetics of the water corridor. Most importantly is maintains and improves the water quality and overall health of the eco-system by filtering pollutants form runoff. According to the EPA, riparian buffers “act as natural filters of nonpoint source pollutants, including sediment, nutrients, pathogens and metals to waterbodies.”

Biophilia - The house sits on a marsh overlooking a river with view to the southeast. The family connects to the rhythms of nature by watching the sunrise move sixty degrees between the summer and winter solstice, seeing the twice daily tide change. The screened dogtrot space enhances the connection to nature. .

Design for Water

The butterfly roof captures the rainfall and will collect it in a future cisterns in the crawl space. The plumbing fixtures are low-flo and meet the EPAs Watersense designation.

Design for Energy

Passive Design Strategies – The house is sited and designed to maximize daylight and natural ventilation with the dogtrot. In a hot humid climate thin, light weight walls areessential to minimize thermal mass and allow for cooling. The large overhang and porches reduce solar gain. In temperate weather, the house can be opened to take advantage ofthe prevailing breezes. Detailing a tight building envelope reduces energy usage.

The house is photovoltaic panel ready for future installation.

Design for Resources

Durability –The materials were selected with resilience in mind. The exterior is clad with cementitious siding over a rain plane which resist rot. Likewise the decking is a composite material which resist rot and mildew.

Local Resources – The resilience of the local economy was another major drive in the selection of materials. The native wood of southern yellow pine was used for the framing, exposed rafters, eaves and exterior shower enclosure. All the cabinets were made by a local cabinetmaker.

Size - The 925 square foot house uses much less materials than the average size house in the neighborhood.

Design for Change

Resilience - In hurricane prone Beaufort, resilience is of the utmost importance. This house is raised up with the living spaces five feet above the base flood elevation to accommodate any future changes in the sea level. It’s built to withstand 140 mph winds, with an engineered lateral support system and impact resistant windows

Aging-in-Place The house is designed for gracefully aging-in-place. The ramp to the first floor assures that the house can be wheelchair assessable. The living is all on one floor. The light switches are thoughtfully placed to provide easy use. The materials are durable and will require less maintenance.