The Diathonite Thermactive insulating plaster was applied to bare brickwork in 5 coats over 5 days totalling 100mm thick (by a plasterer in the same way as any plaster), the coving remade in plaster and then a specialist lime top coat applied. The wall is now insulated but completely breathable so there is little or no risk of moisture build up within the wall and the thermal mass is retained. Due to the cork the thermal conductivity of the plaster is a very repsectable 0.037 W/mK (so similar to other insulations) and at 100mm thick reduces the thermal thermal transmittance (U value) from around 2 to 0.3 W/m2K (so an 85% reduction). It’s a fantastic solution and product, perhaps one way forward for rolling out mass retrofit, the only downside is it takes a long time to fully dry (perhaps a year!) and is not the cheapest of solutions, but if we want truly sustainable, i.e. low risk and long lasting solutions it’s definitely a leading way forward.
