I am in the process of purchasing a Grade II-listed ground floor, mid-terrace victorian flat. The walls are built of rendered masonry and are of solid construction.
A Homebuyer Report advised that there is damp in the kitchen, probably exacerbated by a raised external ground level, and non-permeable vinyl flooring. It was advised that the external ground level be excavated to the meet the internal level, and if this is not possible, full tanking to ceiling height tied in to the floor membranes. Unfortunately the former is not possible because the external ground forms part of a property under different ownership.
On researching the latter option, it seems that there is conflicting advice regarding the use of tanking in older properties, notably in the article by Douglas Kent: http://www.homebuilding.co.uk/advice/existing-homes/renovating/damp.
Does anybody have any advice about the best way to deal with the damp? Would tanking help in the long-term, or simply trap water in the walls externally? Might we be able to manage the issue by returning the room to a ‘breathable’ state, by installing permeable flooring, increasing ventilation, and re-plastering with a permeable material?
Many thanks in advance for any advice,