The Building Conservation Directory 2021

PROTECT ION & REMEDIAL TREATMENT 4.1 145 C AT H E D R A L C O MM U N I C AT I O N S T H E B U I L D I N G C O N S E R VAT I O N D I R E C T O R Y 2 0 2 1 quickly adjusted by occupants according to their needs: rolled back when the sunlight and warmth were welcome; furled or unfurled in response to changing angles of sunshine (this flexibility makes them much more effective than fixed shading such as brises-soleils ).2 The ease with which awnings could be operated must have been another reason for their popularity. Building environments are always dynamic, fluctuating with the changing seasons, the weather and the time of day, but also whenever occupants make adjustments according to their tastes or what they are doing in the space at the time. When people are moving about and exercising, or cooking, they need cooler spaces than when they are sedentary. Researchers have shown time and again that if we are to feel comfortable, we need to have a measure of control over our own environment. Occupants wish to react to improve conditions when they hit ‘crises of discomfort’, and if they know they can take that action quickly and effectively, they will be much happier in the space. Since the second half of the 20th century, unfortunately, approaches to making buildings usable and comfortable have concentrated on controlling air temperature and excluded dealing with more important sources of discomfort. As a result, retrofit actions to reduce energy and carbon use have been forced to focus on sealing the building to retain the temperature-conditioned air. This has had poor consequences for both the fabric and the indoor air quality of buildings of all periods,3 and especially for traditional construction Hoods and fixings for window awnings on an Edwardian house in Bath: hoods are a very common survival, but rarely recognised as such. (Photo: Jonathan Taylor) (which was, after all, designed to be operated in quite a different manner). It is perhaps also why retrofitting has manifestly failed to deliver either reliable comfort or the reduction in space heating and cooling that we need if we are to become sustainable. Another serious concern is that since one of the outcomes of climate change will be much longer summers with much higher temperatures (particularly in cities), overheating will be increasingly problematic, especially if we continue to use large areas of glazing in facades. This seems likely to greatly increase the demand for air-conditioning systems. Alas, air conditioning is not just enormously expensive in terms of energy and carbon, but detrimental to building fabric. It has also now been linked to the spread of diseases such as Covid-19 in interiors. The current consensus among environmental health experts is that we will almost certainly need to encourage a return to natural ventilation in building regulations. Fortunately, our pragmatic predecessors bequeathed us many low-energy low-carbon tools for improving comfort which could be as useful as they ever were, from internal partitions to wall cloths and floor mats. Awnings are potentially one of the most valuable.4 Their enormous energy benefits cannot be doubted. The US Department of Energy estimates they can reduce solar gain alone by as much as 77 per cent, saving 33 per cent of the energy required for mechanical cooling in temperate climates (where they can be enough to make air conditioning unnecessary). Factoring in the additional reduction in direct heating of occupants and surfaces, the benefits are even greater, so it is not a surprise that awnings remain ubiquitous in hot sunny climates. In certain cases, awnings might also help us with one of the trickiest problems in conservation: keeping listed modern buildings with highly glazed facades in use, without having to rely on air conditioning. In England we have tended to try to deal with overheating A Buckingham Palace garden party in 1897, with all the window awnings down on the south-west elevation. Sarah Khan’s research report for Historic England includes a painting of Queen Victoria’s sitting room with the awnings down. (Photo: Wikimedia Commons) Advertisement showing a selection of the many special awning designs produced by Victorian manufacturers (Image: Historic England)