Sustainability and historic homes

19 June 2019

Owners of historic buildings value them because of their space, longevity or sense of identity as well as for aesthetic reasons. At the same time, they want to update them, typically to meet modern service requirements and expectations and/or to help reduce running costs. The responses of the building conservation bodies to many applications often appear to run counter to the environmental agenda.

A question of energy

Over the years, the sustainability message via legislation and funding has increasingly directed building owners towards adopting renewable or low/zero carbon energy sources that frequently have limited outputs for addressing the central issue of using less carbon. Many owners are primarily driven by the need to reduce running costs. The installation costs do not often, over the product’s lifespan, offset the financial savings which is usually the core driver for building owners.  Legislation often blocks use of the most readily available forms of alternative energy, or other ways of reducing energy use.

The effects of properly maintaining and repairing a building are little understood and are not readily calculated in apparent contrast to the savings promised by renewable energy or double glazing. It is also a simple fact that most energy, particularly for older buildings, is used for heating and domestic hot water.

Political pressure for renewables

The public’s perception is often the reverse, with alternative energy and double glazing regarded as the obvious solutions for energy saving for reasons of the simplicity of installation, costs, and overselling. There has been a political pressure to fit renewables to buildings through documents such as the BANES Sustainable Construction Checklist, adopted in 2018, although central government has been pulling back and directing resources to fracking.

The reality is that for many owners, there are few (if any) choices available
because of conservation legislation, issues with the building (ie. they need to
remain in occupation during any works) or installation costs. For many, it starts
with the apparently simple wish to stop condensation by installing double glazing, but that requires replacement of historic joinery. There is also the matter of socio/environmental ‘bling’ – the obvious outward sign that you are considering your environment as well as the practical concerns.

Practicalities of retaining buildings in use

In contrast, the conservation lobby has concentrated on reasons NOT to update buildings based on arguments about embodied energy and that – in ‘reality’ – the building fabric performs better than calculations suggest. That is, the historic building exists and less energy was used in its construction than for any replacement building AND the fabric is not as uninsulated as modern calculations suggest because of hidden voids. Similarly, they acknowledge that the best way of conserving a building is to retain it in use.

However, for many owners, conservation requirements make it increasingly difficult to use the building (cold, draughty, condensation, poor heating and plumbing etc) in line with modern lifestyle expectations. Until the 1950s, most houses relied on fires for heating; the resulting environmental and health problems led to smokeless fuel zones being established and traditional fires falling out of use before sustainability or fuel costs became an issue in most people’s minds.

Mixed messages

This means owners are receiving mixed messages – neither of which addresses their very real problems of comfort and ever-increasing running costs, with statutory energy and water providers’ price rises a fact. On top of this, they face rising maintenance costs involving high-priced materials that need increasingly rare manual skills when compared with standard modern materials or pre-fabricated components. A single glazed box sash costs more than a double glazed UPVC tip out or casement. There is also the fact that, as a population, we increasingly expect to micro-manage the internal environment at the push of a button rather than understand and adapt to a building.

Empiric evidence from sites and research by The University of Glasgow (amongst others) is highlighting how modern interventions can have consequences for the historic fabric that go beyond the purely visual, with moisture build-up leading to fungal and insect attack and decay. It is not all doom and gloom but suggests that for many there is a mis-match between the theory and the reality of retaining buildings in use. A traditional building, particularly if listed, may have few opportunities for upgrading the fabric. However, even small changes to the way in which the fabric is managed or used can have surprising effects for the usability of spaces.

Maximising capabilities

What we can agree on is that any work should start with ensuring the capabilities of the existing fabric are maximised as a way of at least partially resolving the conflicting messages. The measures are frequently very simple but because they are unobtrusive (eg. maintain gutters against leaks because a dry wall is more insulative than a wet one), they have little political or social support. Boring but true: historic masonry can take many months to properly dry out if saturated.

It is also a fact that the effects are difficult to calculate, and the need is often not immediately apparent. We can also learn from the past and use curtains, shutters and doors as intended. They are meant to be practical items to control draughts and improve security and insulation at night. Many modern decorative schemes concentrate on the aesthetic considerations with little thought to practical use. Small amounts of work to window surrounds can have a great effect on cutting draughts, making a room more habitable, therefore requiring less heating. Care has to be taken when installing insulation into voids (typically loft spaces) to ensure the space is weather tight so that the insulation is kept dry whilst maintaining air paths above. This is because wet insulation is ineffective – ventilation needs to be maintained to stop condensation building up and timber decay setting in or plasters and masonry becoming saturated and friable.

Working with and understanding historic buildings

If we are to retain the essence of our historic buildings, we need to work with them and understand them as an organism and use less energy rather than simply bolt on more ‘widgets’ to generate more energy, the economic case for which has often been based on grants and subsidies, that are subject to political and commercial change. The architect Howard Liddell – a lifelong proponent of what we now call sustainable buildings – warned of the dangers of eco-bling and the under-performance of so-called renewable technologies. These include items such as solar cells, micro wind turbines, and other expensive technologies that often have high production costs both in the financial and the environmental sense, frequently under-perform and by definition as manufactured technologies have a limited lifespan rather than take the simple approach and reduce energy requirements.