We know how to build insulated but we don’t know how the thermal performance of building materials deteriorates over time - perhaps we should …
Will the UK Construction Industry be able to build better buildings that provide more comfortable, functional and inspiring environments this year? Can we guarantee continual improvement to new building stock performance?
When I was at university over 30 years ago, one of the subjects that interested me was material science. How do building materials perform throughout their life? How do their thermal properties vary during the life of the buildings? How does the moisture content of an external wall affect its thermal conductivity in summer compared with winter? How does the air tightness of a building change due to expansion and contraction of the building elements in the envelope? How does the aging of the building fabric improve or decrease thermal performance?
Over the last few weeks, I have seen a number of buildings that leak. If water can enter a building and you see buckets catching drips from a leaky roof system or windows, then what does that say about a building’s air tightness?
It is my opinion that once installed most energy consuming systems such as lighting, boilers fans and chillers within the building cannot improve efficiency over time. This may not be the case with the building fabric as the thermal performance could improve if the building could become more airtight. As a building dries out the conductivity of component elements could decrease, resulting in a better insulated building.
Over the last few weeks, I have seen a number of buildings that leak. If water can enter a building and you see buckets catching drips from a leaky roof system or windows, then what does that say about a building’s air tightness? We have seen higher than average wind speeds and plenty of rain over the Christmas period, but surely we must be able to construct buildings that don’t leak. I have also seen some very poor and old fibreglass insulation in existing loft spaces that look like very dirty air filters. Seeing this made me wonder: How does the build-up of dirt affect the thermal performance of insulation? Can the thermal properties of insulation materials improve or do they deteriorate to unacceptable levels of performance during their life?
It is interesting to see that some of these complex issues are being tackled by researchers, both in academia and in industry, and my hope is that this newly gained knowledge will be integrated into emerging new design guidance.
So, I know we can construct good buildings, which are well insulated and air tight, providing very comfortable internal environments. Nonetheless, it is very clear that they need to be monitored and then maintained; this will ensure that we are not wasting our valuable energy resources.
Ant Wilson is European leader for advanced design, applied research and sustainability at Aecom