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,


  • peter ward


    You have answered your question well.. ! NEVER tank.. It would not be allowed in a grade 2 anyway. It WILL trap water and cause problems. The surveyor that recommended that needs to be done for negligence – they are actually advising you to commit a criminal offense – because that most certainly is going to damage a listed building.

    You are not quite right about ‘cant do anything about it’ – high ground levels come under the Party Wall Act – if they are causing problems, you have a legal right to do something about it.

    Drop ground levels, and if you Really can’t, a french drain, combined with total breathability is the answer. Limecrete floor – google Ty Mawr limecrete floor – there is a building regs approved system there -very good, we use all the time.

    A homebuyer report is totally unsuitable for a listed building. You should have been advised at the outset, and the surveyor is seriously out of line for not telling you – its a professional negligence issue. The same surveyor should have told you if he was qualified to survey an old house – there are I think only 6 or 7 conservation qualified chartered surveyors in RICS. I’m in IHBC – the institute of historic building conservation – which knows a lot more about old buildings than rics. It is a major problem in this country at the moment. The advice you have is patently wrong.

    I take issue with Douglas Kent in his advice given in the link you provided, and go so far as to say that what he states is almost criminally wrong – to tell the public that ceramic tubes and electro osmotic damp proofing are anything but complete fraud is very disturbing. I was not aware that the titular head of SPAB has said such a thing and will take it up with him. Please ignore everything said on that page – I cannot believe he’s said it. Certainly the official line from SPAB is somewhat different.

    Getting back to your main question – follow the breathability route – you really cannot go wrong – but do investigate the Party Wall option too – most neighbours, when approached in a sensible and non confrontational way, will help.

    IS the kitchen damp? Or is this just the surveyor poking his ‘damp meter’ in the wall, measuring conductivity, and saying it is. In about 99% of cases, this is what happens. Take any modern materials off the wall, let it breathe, and it’ll dry out. There’s more info on our site – I’m not sure if mods allow links – but if you google heritage house you might find it!

    Good luck!

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