Researching retrofit

Britain has the oldest housing stock in the developed world with 8.5 million properties over 60 years old. This poses huge problems when it comes to the refurbishment and retrofitting of homes to make them more energy efficient, especially as nearly half of them are ‘hard to treat’ with solid walls and/or no loft space.

A key problem is that there are still many unanswered questions in terms of the use of techniques and materials. This is why, as a result of a BRE, government and industry partnership, the Victorian Terrace Retrofit Project at the BRE site in Watford was initiated. Its aim is to generate best practice knowledge of the most effective ways of upgrading existing solid wall dwellings so that they’re not only highly energy efficient and affordable to heat but emit less carbon and meet the requirements of the UK’s ageing population.

Every time I’ve visited the BRE I’ve seen the project progressing so finally to be attending the launch, of what is being described as a ‘retrofit R&D laboratory’, was a notable moment. The project has involved the transformation of a Victorian stable block building, dating from 1855, with an Energy Performance Certificate rating of F, into a row of Victorian terraced houses that are B rated.

What I found at Watford was undoubtably exciting and very useful, although I was somewhat disappointed with some of the ‘historic’ detailing which has been introduced, particularly when it comes to the new windows and doors. There also appeared to be little explanation of the breathability issues associated with solid wall construction and I wonder about some of the insulation methods used – these issues concern Victorian and Edwardian terraces just as much as more ancient buildings.

Of course, what has to be remembered is that this project is a testing ground; it’s not attempting to provide finished ideas or methods. It’s also worth noting that this is not the only research currently being undertaken into how older building perform in terms of energy efficiency. Along with the BRE, the Society for the Protection of Ancient Buildings, English Heritage, Historic Scotland and the National Trust are among the organisations actively engaged in looking at these issues.

The whole purpose of the Victorian Terrace Retrofit Project is to give us much needed data on how old buildings behave when retrofitted with a range of both conventional and innovative products. For example, there are five window and glazing systems installed and 20 different types of floor and wall insulation used in various areas of the building, this means that direct comparisons can be made.

In the coming months, the Victorian Terrace will undergo a programme of testing and monitoring to establish the impacts of this work and, from this, a series of refurbishment specifications will be developed. They will consist of a programme of sequential improvements, each being considered in terms of its CO2 savings and payback periods, so that property owners can make informed decisions on improvements tailored to their individual budgets.

The Victorian Terrace is currently going through a test phase but is expected to open to construction industry and homeowner visitors early next year.

Key features of the project: here

Image credit: Peter White, BRE


  1. Claire Thirlwall on October 28, 2010 at 12:30 pm

    I must visit BRE, it is on my list! The issue of bringing our vast housing stock up to an acceptable standard is an issue that needs addressing. Trying to maintain the character of the properties adds an extra complexity. Do you any interior photos? I’d love to see the techniques used.

  2. Roger Hunt on October 28, 2010 at 12:48 pm

    I’m still waiting for information on when the Terrace is to be opened for tours so do check first before you arrange a visit. The images that I have don’t show a great deal in terms of the techniques I’m afraid.