Gwynne Anthony 2020

ART506 Dissertation 2019. Anthony Gwynne . 66 The report carried out by a structural engineer (Extract of report is provided in Appendix M1 and M2) concluded the hard-non- permeable finishes applied 8 years ago, had cracked externally (cracking is evident in Figure 38), allowing the ingress of rainwater into the cob. The report went on to say the water trapped by the hard non- permeable finishes were unable to evaporate harmlessly away, leading to deterioration and total collapse of the cob (Figure 39). Figure 39: Collapse of the cob wall (Source: Gwynne, 2019). Summary This is a good example of the unintended consequences of applying hard non- permeable finishes to vapour permeable cob walls that traps penetrating moisture that cannot evaporate away. This causes deterioration and collapse 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.