At wits end - damp issues…

[purpleski]

i’m hoping someone can help. I have a basement 175 year old flat in London, which I bought 15 years ago. Since then I have had various damp proof companies and independent surveyors in to look a various damp issues. Recently condensation was said to be the issue so we bought de-humidifiers followed all the guidance. I now have an offer on the flat and the survey has come back as damp in many places. I bought a moisture meter to check for myself and indeed it is damp - some readings on walls 20/21 although most 16 or less. I understand that may not be unusual for age of flat. The worst part is that the moisture readings on some skirtings are 43%! There are no signs of damp except occasional bit of flaked paint! I’m guessing the sale will fall through. But what do I do then? I don’t know who to turn to to deal with this and even if it can be dealt with. I am besides myself with worry. Is the damp coming through the floor?

Don't panic! Through living in old properties I have become slightly obsessed with damp. For older buildings the issue is often that the property was built with 'breathability' baked in, wooden single glazed draughty windows, open fireplaces and materials like lime plaster. We have all moved on from then and installed double glazing, bricked up the fireplaces, applied gypsum and damp proof courses and paint with plastics in. All this leads to condensation as air is trapped in the home. The enemy of condensation is ventilation/airflow. I recommend getting yourself some digital moisture meters off amazon, they aren't that expensive and they are amazing if linked to an app. Monitor the moisture in your home. You should be able to judge what helps reduce the moisture levels. You are aiming for a reading between 30 - 60. Opening windows, the dehumidifier, not drying clothes inside, cooking with lids on pots, keeping your doors open to allow airflow through the flat will all help. I was driven mad and ended up fitting something called a positive input ventilation unit in my flat which really helped.