North Wales Housing – Gwynedd Council
A property housing vulnerable residents was externally insulated after removing concrete render, resolving severe cold and condensation issues without needing to relocate occupants.
Description
One of our properties, housing several residents with learning and physical difficulties was very cold and they were struggling to manage the condensation mould at the property. The property had been rendered in concrete which was causing the historic stone built building to sweat. We identified a need to remove the concrete render. The property needed insulation but internal wall insulation was not an option as we were unable to decant the residents due to their needs and challenges. We decided to insulate it externally.
Project learning
We had recently attended training on managing decarbonisation on older buildings and had heard of Aerogel being used as insulation. We decided to try this material as external wall insulation on this building. Hacking off the concrete did cause some damage to the stone surface which then required a skim to smooth the surface ready for the aerogel panels. However, we had already decided concrete wasn’t suitable so applied lime render. This took a long time to apply and go off which delayed the project considerably. Also, the lime was too soft for the original fixings to hold the panels to the stone walls. Extended mechanical fixings were obtained and this appeared to resolve the issue. Lime render was then applied over the aerogel panels.
Project innovation
We were the first to use aerogel panels as external wall insulation. We did learn lessons that it was a challenging product to use with the lime render. In future, it would be good if a company could incorporate the aerogel into the lime render to provide a superior insulating lime render which can be applied to historic solid wall buildings.
Challenges
We were using a product for the first time and we were not well informed. This did cause some confusion on site with the contractors and caused some delays to the project. Several adjustments needed to made along the way, such as a change to the render from concrete to lime and the subsequent need for longer mechanical fixings. The residents at the property have complex needs so we were trying to minimise disruption to the residents and their carers but the challenges with using a new product caused delays and issues, requiring a lot of assurance to be provided. The end product cost a considerable amount but did provide warmth to the home and increased the SAP rating by 20 points.