Restoration of a heritage building is a complex and specialised activity, especially if the building has heritage status and needs to comply with legislation. Here it is essential to consult with a qualified heritage architect, who will be able to guide you through the process. If the building is not protected by legislation, we have more of a free hand, but we need to navigate the complex decisions around authenticity, practicality and affordability. This becomes even more difficult if we also want to aim for the smallest possible environmental impact.
I was introduced to lifecycle costing several years ago, when I was teaching alongside one of the experts, whose PhD and subsequent research focus has been on this topic. As with heritage, this is a complex topic and one that needs specialist input if we are to have a robust lifecycle analysis. This said, there are some pointers that we can use to allow us to interact with the experts, or just to give us guidance if we don't have the resources to engage with specialists.
In a heritage setting, the first prize is if you can get a material or component that is an exact match to the original that you are replacing. I was fortunate, when doing renovations to my 1930s apartment, to source a door, complete with the original Art Deco door handles, from a neighbour in my building who was doing a conversion. Here the authenticity was 100% and the lifecycle cost was zero, but it is very rare to be able to have such luck. More often, we would need to source the element or material from an outside supplier, which then should give us pause to think of the several implications of our options.
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| Art Deco door handle |
So what is lifecycle analysis? It is an appraisal of the environmental impacts of the element throughout its entire life, from its original mining, quarrying or farming, through each stage of manufacture or processing, throughout the life of the element in use, and its ultimate disposal. One of the most important things that is measured or assessed is the greenhouse gases, whether through a manufacturing stage or, importantly, through transportation.
Another consideration is the embodied energy, the amount of energy required at each stage of the element's lifecycle, either through its processing, or when it is in use. An example of this would be an appliance, which could have quite a high environmental cost in its manufacture but is very energy efficient - over the expected life of the appliance, the higher embodied energy could be outweighed by the much lower "cost-in-use".
If we turn our thoughts to heritage restoration, where we have the added concern of authenticity, how do we get a feel for the environmental impacts? If we need to replace a component, let's say a window, our first question should be: what was the original? What material was it made from? Where did it come from originally? It may be that the windows in the building originally came from a different country or even from a different continent. At the time the timber was farmed or felled, the concept of sustainable forestry had not been invented, so the agricultural practices may have been environmentally damaging, with a large carbon footprint, or a large water footprint. It may have been processed in an artisan's workshop using hand tools, so this would have been very low impact, but what are the modern manufacturing methods? We also need to consider the transportation. To source the identical material may not be practical, affordable or even possible, so what are the alternatives?
First prize would be to find an equivalent window from a local second-hand supplier, from a demolished or renovated building of similar date. The problem with this is that it may not match our building in terms of size or detailing, which would impact the overall aesthetic of our building. So we may be forced to look at manufacturing a replica. If we are striving for the lowest carbon footprint, we may lean towards a local timber from a sustainable forest, but this may not match the colour or texture of the wood in the rest of the building. The alternative may be to find a manufacturer who can source materials from a wider range of locations, but this would impact the lifecycle cost in terms of transportation, and would probably be more costly.
A completely different approach would be to acknowledge that the renovation is being carried out in the 21st Century and not try to mimic the original. This was considered a valid conservation option in the 1980s, where renovations on historic buildings purposely used modern materials, such as aluminium window frames, to contrast with the existing. If we were to follow this route, I would suggest that one aims for simplicity, so as not to draw attention to the new additions. In general, in a historic setting, I have found that the smallest physical footprint will tend to be the most environmentally responsible, the least disruptive of the heritage setting and the smallest financial impact.
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