Hillthorpe is located in a conservation area predominately occupied by large detached arts and crafts properties. The majority of the existing building dates back to the 1930s when the property was extensively extended, further additions were completed in the 1950s. To enter the building you need to pass through a dark narrow opening, which is far from welcoming. The building has not been updated since and is in need of a significant upgrade. Sustainability was key on the agenda for our client as such demolition and rebuild of the existing property was immediately ruled out due to the embodied carbon already in the existing building. The second key point on the agenda was to create a unified home with a large open plan ground floor that made the most of the large south facing garden. ?The result is a series of extensions that increases the existing property by 40% and creates a cohesive building centred around a small pond. Taking cues from the traditional arts and crafts buildings nearby the main double storey rear extension has an asymmetric roof known as a catslide roof. This is a similar size to the gable end of the existing property, so creates a cohesive building, but in true arts and crafts style isn't symmetric. Further additions in the form of dormers allow us to use the full width of the first floor creating much larger bedrooms. A large open plan kitchen dining living room occupies the new extension on the ground floor. The entrance is moved to the front of the building and new double height atrium space is carved out of the existing living room. A new study is created at the back of the property overlooking the adjacent woodlands. A further living room, games room, laundry room, plant room, utility room and WC are located on the ground floor. At first floor a new master suite is created with a balcony overlooking the woodlands. A total of four further bedrooms are created all with double height ceilings. Three more bathrooms, a further study and store room are also created. Rather than a steel framed or concrete structure, the proposal predominantly uses structural timber throughout to reduce the embodied carbon in the building. The vertical window frames on the rear extension are actually part of the structure of the building, these deep frames also help to reduce overheating in the summer as they provide solar shading. The proposal is designed to Passivhaus standards, utilising air source heat pumps and rainwater harvesting to ensure the property is sustainable whilst in use.