John kindly supplied an overview of his excellent talk
Presented at Cambridge Retrofit Conference on the 10th April 2014
Energy efficiency isn’t just about retrofit, but the compulsion to forge ahead with retrofit measures before we properly understand and deal with what are some very basic building issues, is like a doctor treating patients without understanding their health.
On the whole the building industry doesn’t understand the difference between older buildings and new ones and therefore treats them the same. This means we treat our older buildings, which make up about a quarter of the UK building stock, in an inappropriate way. For example, we are lacking some very basic knowledge about how to properly understand and deal with dampness and yet dampness is such a critical issue where energy efficiency is concerned. Research by Cadw (Welsh Government), BRE, the SPAB and others tell us that walls could be some 30% less energy efficient if damp, and this is also cited in the new British Standard on the conservation of historic buildings. It should surely then make sense to focus on properly sorting out dampness problems before anything else, but we usually don’t – we would rather look for something to fix onto a building rather than focusing on the fundamentals of maintenance and repair, when clearly maintenance and repair should be regarded as the very first energy efficiency measures.
At the conference I presented a project called Heritage Cottage, a small terraced house in the south Wales valleys. Built in 1854 and today It’s still almost in its original state. Cadw will be it put into good repair and make thermal improvements, but in the process we will find out about its real energy performance, and also find out about how effective are some common practices of assessing energy performance and building condition. We can do this because we are also carrying out some of the most detailed and comprehensive tests such as insitu u-values, air leakage, thermography and co-heating. This analysis which will provide us with a good basis on which to judge the other common practices used to determine energy efficiency and condition. Many of these tests will be undertaken at three stages: before repair, after repair and finally after retrofit. This will help us understand what energy efficiency is being created by repair and what additional energy efficiency is being created by retrofit. It will be a while before we can see the results of this analysis, but already we know that the real u values of building elements are better than those based on published data, sometimes by over 30%.
The analysis should highlight that repair is an energy efficient measure, but only if it’s carried out properly. Unfortunately there are many instances where those specifying and doing the work think that they are doing everything properly, but this is because of their new construction perspective that is derived from their training and the experience of working with others like them. You might think that a common activity such as repointing a stone or brick joint is such a simple task that there are no risks involved, but nothing can be further from the truth and one needs to look at the detail to understand this. Most will use a pointing trowel rather than a pointing iron – the trowel is principally the tool used to point up a wall that has just been built and the pointing iron, coming in varying thicknesses to suit the width of joints is used to push mortar right to the back of the squarely cut out joint of an existing wall – in that sense it is an energy efficiency tool! If the right tools are not used the work will be inferior and this will also be the case if joints are not cut out to the required square profile and depth. Lime mortar allows moisture to escape and cement mortar traps it – why is it that nearly all traditional buildings will be pointed in cement mortar when they were built in lime?
Whilst the Heritage Cottage project will look at the effectiveness of RdSAP, Green Deal Assessment, the common types of building survey and inspection and much more, it will also look at the effectiveness of a detailed building survey or pathological investigation, which seeks to understand the design, construction, condition and what is effecting this in terms of faults, environment and use, which leads onto understanding how the building performs. Clearly for us, the building pathological investigation is the most important part of the process and should be undertaken as standard practice, as it is the starting point not only to help determine what is needed to make a building energy efficient, but also that it is in a fit state to take retrofit ‘measures’ such as wall insulation. Proceeding without this knowledge can potentially put the investment at risk, put the building at risk as well as the health of those that occupy the building.
John Edwards Not Just Retrofit April 2014 PowerPoint