Four bedrooms new house to be built on a sloping section towards North West. The brief was for a black house of simple geometry.
The rectangular floor plan achieved the brief, whilst the creation of partition walls not to celling height and small separations between elements achieved captivating interior spaces that detract from the simple form.
Spatial requirement: open space that celebrate the view of the city and the hills in the background
The whole of the north façade is glazed, including the northwest corner; this way the entire view is accessible to the whole living area, dining and kitchen. The ceiling is gently sloping towards the northwest corner, this to generate a subtle feeling of being drawn towards the outside.
The building envelope needed be highly thermally efficient as the client wanted a very warm house minimizing the cost of heating
Heating the house is a geothermal underfloor heating system. It consists of two hundred meter deep boreholes retrieving heat from the underground and exchanging it with the underfloor heating fluid. The underfloor heating pipes have been laid into a thin concrete screed above an insulating layer on top of the structural concrete slab. This is to improve the heat radiation.
The roof eave has been designed to keep most of the summer sun out of the building, whilst allowing the winter sun to warm the floors and the two recycled brick feature walls that acts as thermal mass storing the heating and releasing it through the night. The façade features outward opening windows at high level to allow the heat to escape and generate natural ventilation for cooling during summer.
The house has been designed to minimize thermal bridging in the outside envelope. Roof rafters have been increased in size to have bigger spacing between them allowing for better insulation. The timber wall framing has been increased in size for the same reason. The timber wall has been installed with 50mm cantilevered over the blockwork to allow continuous insulation to run on the exterior of the wall; this will allow all the concrete walls to function as thermal mass in the lower storey The steel work has been installed on the inside of other component to allow continuous insulation around it.
Being one of the first builds following a series of earthquakes and expecting more seismic event, the structure needed to be well above the minimum requirement of the building code.
Engineering design has addressed this matter, whilst architecturally we have exposed the big steel columns in order to add a feeling of strength and safety.
Big eaves and no balcony at the first floor were requirements clearly identified at the beginning of the design work in order to avoid any risk of water penetration.
A glass balustrade has been designed at the interior of the big sliding door so that when this is open the feeling of the outside is carried into the dining area, acting in fact as a covered deck.
Photography by Mick Stephenson