Halvorsen Architects have just finished major works to a house in the Grange, a conservation area on Edinburgh’s south side which was first developed as an early suburb from the 1820s.
The clients were keen to expand their Georgian villa in as sustainable as possible. We considered several measures, including renewable heating, insulation and airtightness. With the use of thermal imagery, we were able to identify the areas that were responsible for the highest energy loss and assess which measures to implement, taking into account the cost versus reduction in energy loss.
The clients already have solar panels on their existing, single-storey house. Solar panels for the new buildings, which were to be located to the rear of the existing building, were rejected, partly due to current limitations on battery storage. Instead, we decided to design the new buildings to “Passive House” standards of airtightness and super-insulation. That way, the source of energy (primarily for heating) would become less of an issue.
All the windows of the existing house were replaced with double-glazed windows, using Georgian sash windows at the front, due to the aesthetics and the house being in a conservation area, and larger, modern-style windows at the back, reflecting those in the new build.
Most of the materials that we specified are natural. For the exposed structure of the studio, we used Kerto beams, made from softwood veneers, with timber I-joists used for all the hidden structure. The insulation is a combination of sheep’s wool and wood-fibre board. A mechanical heat and ventilation recovery system has been installed, with underfloor heating throughout.
The new-build consists of a South-facing, self-contained studio to the rear of the garden. This faces the existing villa, while a long extension down the East side of the garden contains utility rooms and a “sitooterie”.
The studio is open plan, with one room that can be shut off as a bedroom, with a hidden sliding door. The Kerto beams, exposed overhead, give definition to the space and are visible over the tops of the low partitions, increasing the sense of spaciousness. There is a large amount of glazing, predominantly to the south.
The garden has been remodelled, including new access from the road, a new driveway and a new footpath to the studio. The rear garden is now on two levels, with a sunken courtyard at the level of the villa and a wildflower meadow at the studio level.