Oireachtas Joint and Select Committees

Tuesday, 10 May 2022

Joint Oireachtas Committee on Climate Action

New Retrofitting Plan and the Built Environment: Discussion (Resumed)

Dr. Caroline Engel Purcell:

Dr. Daly mentioned the life-cycle carbon assessment of three different retrofits in England. The case studies were given to us by Historic England, and we did not design the retrofits. One of the retrofits related to Victorian terraced housing. Dr. Davey mentioned embodied carbon. The retrofit works, which were quite extensive and which I would call a deep retrofit, accounted for only 2% of the total embodied carbon versus 30% for a new build. In terms of carbon savings, therefore, retrofitting is definitely something we should pursue.

There are risks and we need to be careful, but this may be an instance where, if a local authority were in possession of a run of terraced houses, it could pursue solid-wall insulation across them. The risk in not retrofitting the entire terrace is that there might be thermal bridging or there might develop some condensation risks around those junctions. We need to be sure, therefore, about the types of insulation we are using such that it is vapour-open and will not trap moisture. We need to be sure about the specification details such that there is no break in insulation that could become a thermal bridge. Moreover, we need to be cognisant of the impact of these works on the heritage value. We must ask whether what we are doing will change the value, look or heritage of the building to too great an extent. I am afraid the issue has to be taken on a case-by-case basis.