For Balcones House in Austin, Texas, local practice Mell Lawrence Architects chose cast-in-place concrete for its ability to withstand the scorching climate. The thinner exterior wall serves as a buffer against the sun's heat, and the thicker interior wall acts as a thermal flywheel that keeps temperatures comfortable even in the height of summer.
A flat roof with eight-foot overhangs prevents heat gain in the hottest months by minimizing the impact of rays from the southern exposure.
Sited on a plot that slopes upwards towards dense trees to the west, the 4,285-square-foot, boxy residence takes the form of a wide-brimmed, lantern-like, glass pavilion resting atop a concrete base. Adjacent to the main building is a similarly shaped, concrete guesthouse which doubles as an office and art studio. This guesthouse has its back facing the street, and its entrance is gently angled towards the main house to form an entry path between the two buildings.
The box-like interior of the ground floor stretches horizontally along the fully glazed western side of the property. It holds an open-plan dining, living, and kitchen area, and a media and reading room arranged around a smaller volume in the middle of house.
This smaller volume is wrapped in untreated fir and contains the powder room, pantry, mechanical system, and stairs. To the east of the interior box is the media room, where windows are kept to a minimum. The box helps obscure this space to create a darker, more intimate enclave for reading or watching television.
Steel beams with structural fir decking are used for the ceilings to highlight the southern horizontal axis, and provide textural contrast to the lower suspended drywall ceiling and concrete floors.
On the upper level, two bedrooms with ensuite bathrooms are separated by the stairs, and surrounded by floor-to-ceiling glass windows that frame views of the tree canopy and views to the downtown skyline.
A 15-foot-deep screened porch is located along the western-facing section of the upper level, creating a comfortable and protected indoor lounge area—yet with a strong outdoor feel. This porch can be accessed from a corridor, and also from the adjoining master bedroom.
The adjacent guesthouse is also conceived as a box within a box, and the smaller, interior volume conceals a queen-sized pull-out bed, cabinetry, and a fold-out desk and drawers. It also serves as a partition between the front of the space and the bathroom at the back.
Along one side of the wall is a concrete bench that traverses the curtain wall and extends out to the courtyard, drawing one’s line of vision to the minimalist, rectangular pool on the western section of the plot.
When seen from the lowest end of the slope at street level, Balcones House, which has its openings facing natural scenery, looks as if it’s tucked right into the hill.
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