The risks of retrofit – heritage issues

Heritage building in Bath, UK

Respecting heritage in retrofit

In this, the second report on the subject, Kate de Selincout wonders if the ‘tension’ between airtightness and health is blinding other important issues such as the trade-offs that we are often faced with between conservation values and energy efficiency. These can be felt very tangable. While energy efficiency and good ventilation both benefit the building occupants, heritage issues may, on occasion, set one group’s priorities in conflict with another’s, with occupants potentially paying the energy bills – or suffering the discomfort – imposed on them by conservationists’ priorities.


A comment on a petition about listed buildings read: “I am an owner of a Grade II listed money pit. Our Georgian sash windows are due for replacement. They were replaced in 1975, there is no crown glass, spirals instead of lead weights, 32mm bars ie nothing original at all. We have asked for permission to have double glazed, timber slimline replacements, but, once again double glazing appears to be the most hated invention as far as conservation officers are concerned. The temptation just to put them in and say ‘to hell’ with conservation officer is massive.”


Another added: “After 25 years of living in a Grade II listed building our experience has been that the definition and application of Grade II listing of private residential buildings is: unfair and contravenes human rights; unnecessarily restricting and expensive; subjective and opinionated; arbitrary and inconsistent. Its outcome is environmentally unfriendly, criminalising and counter-productive.” It is not just listed buildings where these problems arise. Since the introduction of CESP, a number of pretty humble pre-1919 terraces have been fitted with external insulation, and this too has attracted criticism.


A report in the Architects’ Journal began, “Edwardian and Victorian homes in less affluent areas are seen as being at risk of ‘aesthetic harm’ because intricate features on terraces were being lost after external wall insulation”.


Unfortunately leaving the ‘intricate features’ uncovered is a very unsatisfactory compromise, as Nick Heath pointed out at Retrofit Live, “The planning department sometimes promotes thermal bridges because they insist the installers leave the features untreated.” Leaving the ‘intricate features’ exposed also introduces weak points where water ingress may occur.


Conservationists sometimes suggest that ‘there are lots of other ways of improving energy efficiency’(see link above). However, to achieve the kind of deep retrofit that robustly reduces energy consumption, carbon emissions and bills, while increasing comfort, wall insulation is generally necessary. However, when people don’t have the luxury of living in one house while retrofitting the next, the disruption incurred from installing internal insulation is almost always unacceptable, and installing internal wall insulation (IWI) to the necessary standard may be more expensive than even well-executed external wall insulation (EWI).


Where mass-scale EWI has been carried out on pre 1919 terraces, the reaction from the occupants has tended to be favourable – both about the improved comfort and energy efficiency, and about the appearance.


In some cases, the insulation retrofit has taken place specifically as a regeneration measure, as an alternative to demolition. In these cases, as Nigel Banks of ‘Keepmoat’ points out, the EWI could itself be seen as a valuable agent of conservation. Buildings, street patterns and, crucially, homes and communities, are all conserved.


Colin King of the building Research Establishment (BRE) wonders about the merits of getting hung up on the traditional appearance of homes that are miserable to inhabit: he points out that while there are people who really love traditional working class terraces, “they aren’t always the people who live in them”.


“If you ask the occupants, they will often tell you their house is horrible, cold and damp”. So when people say “we have got to protect the character of these streets” that’s not the occupants who can’t afford to heat their home. “They like their neighbourhood and community, not the houses,” he says.


There is an important question to ask here. Historic buildings hold a great charm for many of us, and may have meaning for some who live or work around them. But how much should other people be expected to pay for our delight with their health – and their energy bills? And how much should the planet pay? This seems to be a discussion we need to have.
Kate de Selincourt


This is part of a larger story in this issue by Kate.


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