The National Preservation Conference is this week in Tulsa, Oklahoma. Staff members from around the National Trust for Historic Preservation will be blogging from the conference and sharing their experiences. Today, Barbara Campagna, Graham Gund Architect of the National Trust for Historic Preservation, is reporting on one of yesterday's educational sessions.
John Fidler (Simpson Gumpertz Heger), Sarah Staniforth (The National Trust) and Chris Woods (English Heritage) in Tulsa Wednesday morning.
Three conservation leaders from the United Kingdom presented the “English Sustainability Experience” to a packed room in Tulsa Wednesday morning. John Fidler, formerly of English Heritage and now a principal at Simpson Gumpertz & Heger in Los Angles, developed and moderated a session with his former colleague Chris Woods, director of buildings at English Heritage and Sarah Saniforth, historic properties director, at the National Trust. Sarah discussed the impact that climate change is having on their historic properties, while Chris presented their current sustainability research including some much needed research on the energy efficiency of windows.
John started the session by posing the question: In trying to reduce carbon emissions, what if well-meaning changes threaten to endanger our environment? He believes that some of the metrics being used to evaluate sustainable design have not been properly clarified and agreed to, leading to differences in the perception of values. Indeed, efforts to define social sustainability values and economic sustainability could even further negatively impact our heritage. Decades of neglect and little investment leads to slum clearance and wholesale redevelopment, while whole life costing tied to embodied carbon modeling has been using carbon calculations (15-20 years) assigned by bankers and investors that are likely less than the true value of our material culture. In terms of ecological sustainability, models suggest that melting ice caps will cause a breach of the Thames and catastrophic flooding of London.
Sustainability & Climate Change: Impacts, Mitigation & Adaptation
The National Trust (for England, Wales & North Ireland) has a mission statement which begins “Conservation is the careful management of change.” While their motto may be “For ever, for Everyone”, in our current climate, how long can we reasonably expect to be looking after things? The National Trust has been measuring the impact of climate change to their properties (over 50,000 built structures!) for years now and their methodology will indeed help me formulate the approach to measuring the impacts to our own historic sites in the US.
A view over the lake at Stourhead to the Pantheon which is framed in autumn foliage. This bucolic view is often changed by the growth of algal blooms which is managed by dropping barley bales into the water. (Copyright NTPL/Nick Meers)
In England, they are specifically identifying impacts to their properties from warmer temperatures, drought, coastal erosion, storms, flash floods and heavy rainfall. At Stourhead in Wiltshire, for example, a very wet summer followed by a crisp, frosty winter led to a “soup of green algae” in their bucolic lake. It should be noted though that it wasn’t climate change alone that caused this algal bloom. The nitrogen run-off from synthetic fertilizers used in the region combined with the unusual rainfall have presented the perfect conditions for the algae growth – a sort of one/two whammy from human impact. One of the most arresting images, was the slide of historic cottages dropping off the side of cliffs in Cornwall as coastal erosion overwhelms the coastline. Again and again, Sarah showed devastation at their properties which may have been caused by increased rainfall but was often exacerbated by irresponsible land use.
The National Trust is taking direct action to mitigate these impacts, wherever it is reasonably possible. These efforts include:
- Reduce emissions of greenhouse gases: Changing to low energy lightbulbs including the ubiquitous CFLs. But they’ve gone one step further by working directly with light bulb manufacturers to develop new low energy bulbs for their historic fixtures.
- Improve energy efficiency of their buildings: Here, because of their massive landholdings, they are actually able to use their own sheep to produce thermafleece for insulation, for example.
- Reduce carbon footprint: They are evaluating their fuel sources, changing to more efficient boilers (often developed by German companies) and avoiding the use of electricity from non-renewable resources.
- Generate energy on site: They have begun using thermal and photovoltaics at many of their sites including directly on the roofs of some of the Grade 2 listed buildings. And on support buildings of lesser importance at some of their sites, they have begun installing the PV slates.
- Reduce embodied energy: In an effort that Sarah calls “slow conservation” (which she compared to the “slow” food movement) they are looking to building new construction in ways more sympathetic to the environment.
In order to adapt to these climate induced changes, the National Trust is looking at short, medium and long term adaptations such as installing larger gutters, going back to traditional practices (these were often done for good reason) and most importantly, managing properties better with cyclical maintenance programs.
Resolving the Conflict Between Energy and Building Conservation
Chris Woods discussed the efforts that English Heritage is undertaking to challenge the assumption that older buildings are inherently energy inefficient. As quoted from their website,
Traditional buildings can often perform extremely well in energy tests. Thick walls and relatively small windows give a high thermal mass, which means they stay warmer in winter and cooler in summer than many modern houses. This is true even of the most unexpected buildings: for example experiments have shown that 16th-century half-timbered houses can sometimes out-perform modern buildings. Older terraces are usually easier to keep warm than detached houses, simply because they have fewer walls through which to lose heat.
Buildings account for 46% of carbon emissions in England, a percentage on par with that in the US. Their basic precept is that we must change human behavior and think holistically when evaluating the energy use of our buildings. Don’t just assume the energy loss is primarily from the windows, look at all the features of a building to determine the actual impact. English Heritage is just completing a comprehensive window study whose results have not yet been released but like many of the smaller studies in the US and our own anecdotal beliefs, it appears that this study will confirm in some respects that the older windows constructed of traditional, maintainable materials and assemblies can be as efficient if not more efficient than newer high performance ones. This is a study that we at the US National Trust are eagerly awaiting and will help us in framing the approach of our own window study which we are undertaking with Lawrence Berkeley Laboratories in California.
The UK websites
Both English Heritage and the National Trust have terrific websites detailing the impact of climate change and offering many mitigation tips. English Heritage: www.climatechangeandyourhome.org.uk/live/homepage.aspx
The National Trust (www.nationaltrust.org.uk) has sections on both climate change and environmental practices. I urge you to peruse these sites to help you in thinking how to change your behavior.
-- Barbara Campagna
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