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To answer this question it would be best to visit the property to see how the house works.
Best to get an on site survey/quotation done, this is a free service to you and you will get 3 quotes. Simply post your job onto rated people's site.
You are not obliged to go with any of the quotes- but every job that's posted is paid for by the relevant tradesmen .if they contact you that means they are interested in your job. If one of them are awarded the job then great news for you both.
Hi Anne, firstly you will need to diagnose the cause, ie' rising damp, condensation, broken, leaking rainwaterpipe, there are many possible causes. Decoratively you should wash the area with diluted bleach, rinse off and leave to dry. Once the areA is fully dry, stain block it with a polycell or zinsser stain block paint and decorate it how you would like it.
A.L. SMITH DECORATING SERVICES
Easy way is to wash it off. I would assume you would not want just a temporary solution
and if the above will work will depend on how long was the mould left to grow,
if you have a wallpaper on the wall , how deep has the mould grown in to the wall/plaster or
if you have a leak problem?