Dry rot and plaster

If the plaster shows visible mycelium, strands, or fruiting bodies (white cottony growth, grey strands, rust‑coloured dust). then yes you will need to remove the plasters, but if they are dry and mycelium strands are not behind the skirting and running into the plasters, the plasters should be fine. good luck Joseph

Hello, The cement based plaster should be removed back to brick and a 3x coat lime plaster system applied. This will prevent further issues caused by condensation. Cement based plasters (including gypsum plaster and bonding) are far less breathable than lime putty plasters and mortars. Provided the ventilation issues have been improved and you have sufficient cross ventilation under the floor, further chemical based treatments are usually not needed as through the change of temperature and moisture levels bacteria will not survive and wood boring insects will move away to look for better habitats to thrive or die.

A chemical treatment is a waste of money if it's a condensation/lack of ventilation issue, it will also depend on if the outside wall has been rendered or repointed with cement as this will hold in moisture