Gwynne Anthony 2020

ART506 Dissertation 2019. Anthony Gwynne . 64 Summary This is a good example of the unintended consequences of applying hard non- permeable finishes to vapour permeable walls that traps rising and penetrating moisture that eventually pushes through the finishes. This causes damage and deterioration of the building fabric, rotting timber embedded (joists/rafters) or attached to it (skirting boards etc). The dampness reduces the thermal insulation of the wall and eventually leads to mould growth. Case study 5: Collapsed cob walling renovated with hard non- permeable cement render and internal plaster board finishes in December 2019. In December 2019, this report author became involved with this project when asked for advice by the insurance loss adjuster’s surveyor how to reinstate the collapsed cob walls for this property using vapour permeable materials. According to the owner the semi-detached cottage is unlisted and was built between 1790 and 1830. The first- floor walls are constructed of mud (Appendix M1), also called cob built over ground floor stone walls. Cob consist of mixtures of locally sourced clay soils, chalk, and sand, with straw to bind it all together (www.historicengland.org.uk) . The walls are approximately 400mm thick built over the ground floor stone walls. The owner claims the cottage was renovated about 8 years ago (Figure 37) . Figure 37: Cob walls renovated with non- permeable finishes (Source: Gwynne, 2019).