We have recently been working on a Passivhaus retrofit of a community building in Gwynedd. The building belongs to the village choir but is used by other local community groups and the choir wants to keep long-term running costs as low as possible so that these groups can continue to use the space. Interestingly, the building started life as a Scotch Baptist Church, built in 1918. It has many of the same issues as small churches and chapels in Wales. Part of the property is built into a bank, and this wall has been very damp in the past. The rest of the walls, being solid stone with rubble infill, have also let water into the building and developed mould. One wall in the back of the chapel was inappropriately repaired (partially to avoid rain entering the building through the wall, as it faced the prevailing winds.) But after the render started cracking, the wall started letting water enter the building, and the external render then “locked in” any water entering the building and made the wall even worse.

We effectively insulated the building in wood fibre, with a 100mm layer installed on the walls, alongside 400mm of loft insulation in the roof. 100mm of insulation is quite far below Passivhaus standards but is about the maximum we could achieve on this particular building, after modelling the moisture movement through the wall. We sealed the wall built into the bank in order to deal with the moisture issues on that side of the building, and we also sealed the back wall as a temporary measure to deal with moisture entering the building, until a longer-term solution could be found to the render.

An air conditioning heat pump was installed to provide heating, and a mechanical ventilation with heat recovery is being installed to provide fresh, filtered air. Many elderly people use the building and we believe the ventilation system will make the space safer during the Flu, Cold, and Covid seasons.

Triple glazed windows and insulated doors are also being installed at the property and there are plans to install a solar panel and electricity storage battery system in the spring, ready to generate power over the summer months.

The end result should be a very low cost-to-operate building, with very minimal carbon emissions, that will provide a safe and comfortable venue for community groups in the village.

The total cost for the renovations will be approximately £165,000. Most of the funding was provided via grants – with thanks to Mantell Gwynedd and Cist Gwynedd. One further grant is in the process of being considered, which will hopefully pay for the solar panel and battery system.