Daniel Lockwood’s recent article discussed the key principles of the Passivhaus standard which achieves reduced energy demand and carbon emissions in new buildings through careful design considerations. There is also the EnerPHit standard available for refurbishment and retrofit projects where the existing architecture and conservation issues mean that meeting the Passivhaus standard is not feasible.
Working on an historic building refurbishment project presents the added challenge of working within existing constraints to achieve the performance standards of today. This article explores the ways in which the environmental performance of a historic building can be improved.
Traditional Energy Sources
Buildings are major consumers of energy throughout their lifecycle. The main sources of this energy have typically come from fossil fuels such as oil, coal and gas which cause environmental pollution by emitting carbon into the atmosphere when they are burned. Throughout recent years, increased awareness of environmental issues has resulted in a greater drive towards creating sustainable buildings that do not contribute to the declining condition of our environment. This includes using renewable energy sources that naturally replenish or are practically inexhaustible.
Sustainability is often defined as meeting the demands of today without compromising the demands of tomorrow. As a Project Manager working on schemes that involve new build and the refurbishment of existing historic buildings, I have noticed an increase in client focus on creating sustainable buildings. For example, sustainability is now a priority for students who no longer accept buildings that are not aligned with their own values around environmental performance. With student satisfaction ratings being such an important target for many higher education institutions, this is becoming a major driving force for building design in the sector.
Opportunities for Improvement
Due to the introduction of the Building Regulations and the numerous environmental performance accreditations available, upgrading a historic building to meet the standards of today can present several opportunities for improved performance. Some of these opportunities include careful specification of materials, selection of construction technologies and creating a renewable energy strategy for the building.
When there is a historic building involved, it is crucial to fully understand the extent of any listings and what this comprises. This will highlight what constraints are in place so that the scope of any improvement works can be confirmed.
One of the main opportunities for improving environmental performance is in the building fabric. We have recently led an options appraisal on a higher education scheme at the beginning of RIBA Stage 2 to compare various foundation and structural frame solutions to understand which option provided the best environmental performance. For two of the new buildings proposed on site, the use of timber glulam beams was investigated to offset the impacts of steel and concrete which have more embodied carbon. Materials such as aluminium timber composite glazing, zinc roofing instead of copper and thinner rainscreen stone cladding were designed to lower the overall level of embodied carbon while still meeting the client brief. Of course, cost is also a major factor which can often cause conflicting opinions between stakeholders which is why it is so important to consider these aspects as early as possible in the design process.
Site Energy Strategy
Thinking about the site-wide energy strategy for a development, steering away from fossil fuels such as gas provides opportunity to explore innovative solutions. On the same project, we have investigated using the river as the main heat source, with air source heat pumps as a back-up supply. Depending on the location of the site, there may also be opportunity to use underground water as a heat source. Where a site is located near old mine shafts, there could be the option of using the water in these shafts as a heat source. We are currently investigating this in the feasibility stage of a potential project, supplemented by photovoltaic panels to harness solar energy.
It is exciting to see these renewable technologies being investigated for use as the main energy source for the buildings, which will hopefully become more popular as they become more frequently used. I feel it is important to remember that although certain works are understandably restricted in historic buildings, the majority of buildings are there to serve a purpose and therefore need to retain this purpose in a way that has the least impact on our environment for the years to come.