Photo Credit: © 2019 Alexander Herring

Split Box House

The Split Box House, for a busy working couple and their three children, is located near Emory University and the CDC in Atlanta, Georgia. The client’s wanted a house that is a quiet, restrained, escape from the excessively noisy digital world that overly stimulates their daily lives and is a reaction to the surrounding banal spec homes each a louder spectacle than the next.

Simple and clean in its form the house started as a twenty-two foot wide extruded box. That width was chosen based on the distance a reasonable size wood truss can span. This ensured that no interior support walls were required allowing for an uncomplicated open floor plan. Arranged in an efficient pattern to eliminate waste, the primary exterior cladding of the box is a low maintenance grey cement panel. The panels, attached as an open joint ventilated rainscreen system, help manage moisture intrusion and reduce energy consumption.

Cut to the desired length based on the space requirements of the family, the box is subsequently split into public and private volumes allowing for a clear delineation between functions. The private portion is rotated ninety degrees around the sky-lit stair hall to maximize views to the serene woods behind the house. A complimentary warm ipe wood, alluding to the softer interiors of the house, clads the cuts. The exposed roofs are covered with vegetation to reduce stormwater runoff, mitigate energy consumption and improve air quality. Comprised of the bedrooms upstairs and the guesthouse on the main level, the private functions bridge across a covered breezeway creating an outdoor room with a view corridor to the woods and access to the main and guest house entrances.

The public functions move through a series of low and tall spaces culminating in a double height sky-lit space. The skylights provide shifting light patterns throughout the day and are operable to create passive cooling during the warm months. The houses six skylights and the low-e insulated glazed windows use sunlight instead of artificial light for illumination to decrease the house’s energy consumption. Lined with cabinets on one side that serve as storage, housing for the entertainment center, fireplace, dining room buffet, refrigerator, and freezer allows the public functions to stay open, clean, and uncluttered. The quiet interiors create a relaxing calm environment that is about the space itself and the views to the outside.

A series of site walls, carefully nestled into the steep lot which slopes forty-two feet down from the front to the back of the property, cascade down the hill from the street to create a terraced entrance garden that becomes the exposed foundation of the house. Long grasses, appropriate for the climate, reinforce the simple geometric forms of the house with their naturally soothing sway and unify the engineered slopes that mitigate the grade differences of the site. The manicured lower lawn adjacent to the grove of trees give way to the ever changing natural beauty of the woods beyond.

Design Challenge

The most challenging aspect of the project was the site. From front to back the property slopes forty-two feet down from the street. This creates aesthetic, grading, and drainage difficulties. The existing house, which was subsequently demolished, sat about sixteen feet down to the front door threshold and had a full basement. The code required the new front door threshold elevation to not be more than two feet higher than the previously existing structure. Visually being far below the street puts the upper floor at eye level creating an unusual relationship between the house and the road. To solve the unique relationship to the street, building a taller house was considered but the maximum height is capped at thirty-five feet making this solution not feasible. Pushing the house forward up the hill would have allowed the house to be raised two feet marginally helping, but a separate code requirement does not allow for a new house to sit further forward then its neighbors. A solution for the grading and drainage challenges would be to push the house back on the lot to reduce the steep front. But this was not a viable option because it would require a large amount of fill to be trucked in to maintain the required finished floor elevation and to fill in the basement of the original house. Adding to the complexity of the issue the client wanted a flat grassy area for their children to be able to play in the backyard. The only practical solution was to build the new house in the location of the old house. To solve the grading issue and create the required play space, a small portion of the backyard was regraded, keeping the cut and fill neutral to avoid the expense of trucking dirt in or out. To alleviate the steep front, an entrance garden terrace with steps was created to allow easier access to and from the street. Drainage concerns were resolved with a doubled series of perforated drainage pipes that catch water coming down the hill and direct it around the house. Aesthetically, a sloped roof would have seemed overwhelming and disproportionately large based on the relationship between the house and the street, so a flat roof was chosen. To mediate the visual impact of looking down on the lower flat roofs, they were covered with plants.

Physical Context

The surrounding context of the Split Box House had a substantial influence on its design and placement starting with wanting to preserve the natural beauty of the site. The large specimen trees were left undisturbed by using the footprint of the demolished house which had previously been excavated for a basement. The existing steep grade also remained and created the opportunity to engage the house into the hill. A series of concrete planted terraces were inserted into the slope to provide a link from the house to the street. As the gardens, planted with drought tolerant grasses and a Japanese Maple tree, descend down the hill they merged into the exposed portion of the basement. This daylit concrete footprint allowed for doors and windows on much of the floor using the natural grade of the site to its advantage and created direct access to the patio and grove of Trident Maple trees. The main public living space of the house containing the living room, dining room and kitchen is stacked on top of the exposed concrete portion of the basement. This allows the large glazed areas of the rooms to feel like they are inserted into the canopy of the trees creating a strong connection to the exterior. With the addition of skylights to the space the ever changing natural light patterns and mood of the day reflect the inherent conditions of the exterior on the interior. Additionally, the skylights are operable to create passive cooling during the warm months. The splitting of the box and the turning of the private portion ninety degrees creates a large opening and exterior space through the house. As you approach from the street your eye is drawn towards this void revealing a framed scenic view of the tranquil woods beyond. This outdoor living space, also serving as the entrance to the main and guest houses, is cooled naturally by the air flowing down the hill creating a comfortable breezeway. The bedrooms bridging across the top are oriented towards the woods providing serene views. These views become the backdrop to the green roof for several of the bedrooms. Bringing nature to the upper level of the house, has sustainable benefits and provides a more intimate relationship with the outdoors. This allows every floor in the house to have a direct connection and access to outside vegetation. The exterior landscaping on the upper portion of the site is an engineered landscape that mitigates the large grade differences. It uses more precise slopes which complement the house’s geometry reinforced with long grasses that have a natural soothing sway. A manicured flat lawn section, that was created as a play area for the children, drops off at the small newly constructed retaining wall as it gives way to the natural undisturbed environment at the back of the property.