Updating a Stone Farmhouse and Barn to Create an Energy Efficient and Comfortable Home
This case study is about adding insulation and secondary glazing to make a stone farmhouse a more comfortable home to live in.
About the property
This stone farmhouse with barn is thought to have been built in 1820. Before the current owners, it was last lived in during the 1960s as a smallholding or farm. In the 1970s it was sold and then rented out as a holiday let. Hoggerstone Farm is not a listed building. When the current owners bought it in 2018, it had been unoccupied for 20 years.
About the adaptation
The project aimed to bring the farmhouse and converted barn back into use as a home.
Work carried out to the farmhouse during the 1970s had removed many of the building features that might have been considered architecturally significant.
The new owners wanted to undo the harm done in the 1970s and sensitively reveal and reset the original farmhouse as a contemporary home. They used the services of a conservation accredited architect, a sustainability consultant, structural engineers, mechanical and electrical design consultants and a heat pump installation company.
The strategy was to make the building as energy efficient as possible, using a thin layer of breathable insulation throughout which is considered a low risk approach to retrofit.
The owners chose insulation products and solutions that would work with the historic fabric technically but also allow the character of the historic building and its atmosphere and features not to be lost under a thick layer of insulation.
As well as insulation, the energy efficiency adaptations included the re-rendering of stone walls internally to remove any cement and the installation of:
- Double glazing
- Secondary glazing
- Solar panels
- Heat pumps
What happened during the planning process?
The building stands in an Area of Outstanding Natural Beauty and it is not a listed building.
A sustainability consultant was employed by the owners to steer the initial strategy for the retrofit. The planning consent application was successful.
The installation process
The insulation installed consisted of:
- Floor: insulated limecrete flooring system
- Walls: 60 millimetre layer of breathable lime-based insulating plaster over repointed (to remove any cement) 500 millimetre stone wall. Painted in breathable paint
- Windows: internal secondary double glazing for one existing single glazed sash window. For the other windows, a mix of 24 millimetre double glazing to openings without glazing bars and 14 millimetre slim double glazing to openings with. Window frames were painted using linseed oil paint
- Roof: a mix of 200 – 300 millimetre timber fibreboard with vapour control and breathable membranes.
Impact and lessons learned
- The farmhouse has been retrofitted to make it a comfortable home to live in and to reduce the carbon footprint of running it as a home. Because the building had been unoccupied, it isn’t possible to compare current energy bills against bills before embarking on these energy efficiency improvements.
- The owners feel that the project has been successful in retaining the character of the existing building while allowing for a larger family home to be integrated.
- Insulating above the rafters has allowed the sarking boards and full extent of the existing timber roof structure to be revealed.
- Secondary glazing has worked well to avoid condensation.
- Larger rooms, such as in the converted barn, will only heat to a comfortable level with the help of the log burner. In hindsight, the owners think they could have considered additional insulation in these spaces.
- Using electricity as the only energy source has made the farmhouse vulnerable to power cuts. It has been necessary to use the log burner for long periods of time when power has been cut, so it has been very important to have that second source of energy.
