Grace Fletcher from 5th Studio discusses the battle to retrofit our historic housing stock and how the practice has teamed up with Barclays bank on a pilot retrofit pattern book.

What’s the project and how did it come about? 
The retrofit of existing homes is one of the greatest opportunities to reduce energy demand and national carbon emissions. We decided that we’d create the greatest impact and support for realisable and fundable solutions if we worked directly with banks and mortgage lenders. Barclays embraced the idea of creating a pilot Pattern Book for Retrofit and supported the creation of this both financially and by setting up a working group to rigorously test the concepts and content. 

How do your pattern books compare to architectural pattern books of the past? 
Historic Pattern Books were aimed at builders and landowners, providing enough guidance and detail for non-architects to build in an approved style. They are still published today in the form of CAD packages, supporting both the construction industry and prospective households. This Retrofit Pattern Book has been prepared in the spirit of its 19th century forebears, to provide general guidance to improve the energy efficiency of the Victorian terraced house. The retrofit details identified map onto the traditional details that would have formed part of an original pattern book.  

Who is your target audience, and how do you intend to reach them? 
This book is aimed at homeowners, landlords, and perhaps building tradespeople, and is intended to provide a guide to how this type of house evolved (as an empirically developed typology that responded to the construction methods, the mores and expectations of the day) and so improving the homeowners understanding of how retrofit could benefit their property, comfort, energy use, and the climate. 

The aim initially was to reach homeowners, landlords, and tradespeople through the bank but, as the wider relevance and quality of the book emerged, it was agreed to widen publication through the National Retrofit Hub – and hopefully other – independent websites. By categorising retrofit measures by timescale and complexity as well as cost and energy saving, the book makes clear that some measures or levels of intervention will require architectural and other professional input. 

What are the most common mistakes people make when retrofitting properties?

• If basic maintenance – leaking gutters and downpipes, repair roofs, eliminate damp from raised external ground levels – isn’t carried out then this will reduce the effectiveness of any retrofit works. A wet wall will conduct away more heat than a dry one. 
  The Pattern Book addresses these issues in a couple of ways: ‘5 things to do’ – p36 and ‘some Common Misconceptions’ – p38.  
• The improving of insulation and air-tightness without improving (passive or active) ventilation often leads to the exacerbation of current issues with moisture, condensation, and mould – affecting the health of the building fabric as well as the occupants. 
• The aggressively marketed and currently grant-funded emphasis on heat-pumps over a fabric first approach can lead to a situation where heat is decarbonised but running costs increase and comfort decreases. The cost differential between electrical and gas prices can effectively cancel out the cost effect of the improved efficiency of heat pumps over gas boilers. Additionally, the lower efficient operating temperature of heating by ASHP can lead to a need to change existing radiators to get homes to anywhere near desired/customary temperatures. 
  As the book shows, heat pumps are an essential part of a strategy to reduce demand and to decarbonise the energy supply , but it can often make more sense to install a heat pump after making some key fabric improvement measures. 

How do you see the relationship between a DIY approach and the role of the architect? 
It is important that people understand their homes, which are possibly the biggest investment in their lifetimes but, often taken for granted in terms of condition or performance. Understanding how the fabric of the home behaves in terms of thermal and moisture movement is key to comfort of both fabric and occupants. This understanding will allow many maintenance and retrofit tasks to be undertaken on a DIY basis. Beyond that, the differences between a DIY and an architect-led approaches are only those of scale, any need for consents (listed building, conservation area, building control, etc), and the capacity to commit time and experience to the process. 

Read 5th Studio’s Retrofit Pattern Book here.