Building performance is the sum of many parts

With spiralling energy prices getting building performance right is becoming even more critical. Getting it right is a major challenge as there are many stages to get through from the stroke of the designers pen – or keyboard - through to the completed building. Take insulation as an example. How this performs in use often falls to a fraction of the manufacturers performance data or expectations. Initial work done by several reputable research bodies has identified that insulation performance varies considerably between as tested and as installed.

This is also an emerging theme for many other materials components and systems. One main reason is how insulation interfaces with other materials and assemblies, an area where there is very little information available. Water and humidity levels affect nearly all insulation products, performance is also significantly reduced by air flow. These need to be properly detailed to ensure optimum performance, a process which is down to the skill and experience of the designer.

It’s not really sustainable to over design to achieve the desired result but that seems the only option at the moment to ensure buildings perform as set out in the initial specification.

Problems occur when this carefully worked up relationship between detailing and materials is lost on less experienced members of the team. There is a risk this detailing is lost for cost reasons by simplifying the build process. A good example of this is a roof. Roofs have to contend with a great many forces and conditions including wind and rain. I continually come across perfectly decent waterproofing solutions but little or no consideration is given to the materials that surround it or the substrate it sits on. Often these are the cheapest and give impressive guarantees. Looked at as a complete roof they are hardly viable with the result the insulation gets damp and the thermal performance of the roof drops off dramatically.

There is a lot of research going in this area but there is a big challenge as apart from the loss of skills on site we have also seen a loss of controls and quality checking. It’s not really sustainable to over design to achieve the desired result but that seems the only option at the moment to ensure buildings perform as set out in the initial specification.

Some realism is needed here so that we can actually deliver the performance, talking the talk is not good enough walking the walk is needed, and that will bring down the bills, and the carbon emissions.

Peter Caplehorn is technical director at Scott Brownrigg