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Guide offers real-life advice on energy-efficient renovation


By Features Reporter


By Martin Sherring, trustee at The Pebble Trust

Martin Sherring, of The Pebble Trust.
Martin Sherring, of The Pebble Trust.

Two years ago, Penny Edwards and I, both Black Isle residents, met an old friend, Chris Morgan. We were all concerned about the slow progress and limited ambition for making Scotland’s housing fit for the coming low-carbon environment.

Chris is a director of John Gilbert Architects, former chair of the Scottish Ecological Design Association (SEDA) and one of only four Scottish architects accredited to “Advanced” level in Sustainable Design. Penny and I are trustees of the Pebble Trust, a Highland charity focusing on issues of sustainability.

That meeting led, eventually, to a book – Sustainable Renovation – Improving Homes for Energy, Health and the Environment – written by Chris, published by the Pebble Trust, and adopted by SEDA as a guide to best practice in home renovation.

If anything, the need for the book has become even more obvious since we met. In an effort to reduce both carbon dioxide emissions and fuel poverty, Scotland is on the verge of a huge programme of investment in the fabric of our housing, with an estimated £11 billion to be spent in the next few years.

An example of thermal bypass. This is where cold air enters the fabric of the building, but not the house itself. Here, cold air from a join when a conservatory was added is getting in and through gaps in the insulation, cooling the wall and increasing the risk of condensation and mould.
An example of thermal bypass. This is where cold air enters the fabric of the building, but not the house itself. Here, cold air from a join when a conservatory was added is getting in and through gaps in the insulation, cooling the wall and increasing the risk of condensation and mould.

This is undoubtedly necessary, and there is equally no doubt that current retrofit efforts are saving energy and improving comfort for thousands. But many renovation projects are not as effective as anticipated, and in some cases the “improvements” have actually made things worse.

Clearly there are lessons to be learned if we are to make the most of the £11 billion, and the new book identifies four broad areas where current practices could be improved.

The first important difference between our guide and others is that we aim for a balance between energy efficiency, the comfort and health of occupants, and the durability and condition of the building fabric.

The main issue here is moisture – it’s easy for insulation work to trap moisture in the structure of the building, or to create localised cold spots where condensation and eventually mould appear. Not only can this affect the residents’ health and the structure of the building, the presence of moisture also reduces the energy saving, so sometimes this more balanced approach actually leads to better energy efficiency.

Unusually for an architect, Chris has some experience of “building performance evaluation” – comparing what actually happened when improvements were made with expectations before the work started.

If improvements in insulation and airtightness are not accompanied by an improvement in ventilation, it can lead to problems. The Sustainable Renovation guide seeks to avoid these problems by adopting a more holistic approach.
If improvements in insulation and airtightness are not accompanied by an improvement in ventilation, it can lead to problems. The Sustainable Renovation guide seeks to avoid these problems by adopting a more holistic approach.

This leads to our second difference – our guidance is based on energy consumption in real buildings once completed and inhabited, rather than mathematical models. The models are a necessary simplification of what happens in practice, but there are any number of differences between the real world and the way it’s represented on a spreadsheet – and we think it’s vital that we learn lessons from that.

Thirdly, the way people behave in the buildings makes at least as much difference as their thermal properties. Thus in the book we consider how to engage with people to make sure they understand the changes that are being made, and how to make the most of them.

Lastly, we take on board the lessons learned by the conservation or heritage in working with existing buildings. They mostly use a palette of natural materials, carry out routine maintenance, and respect interesting features which give buildings their character. All these are just as important in any older building as they are in Scotland’s castles and abbeys, but much insulation work ignores them.

The guide is designed to appeal to everyone, from the concerned homeowner to the architect, and from the builder to the “policy-wonk”. It covers the general principles we recommend and then has chapters with specific proposals for each part of the building.

Sustainable Renovation guide.
Sustainable Renovation guide.

A hard copy of the guide can be purchased for £10 (plus P&P) from SEDA or the Pebble Trust websites, and can also be downloaded for free as a pdf from the same websites.



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