Hi, I’ve just bought a 300+ year old stone house in Northern France. In one room there’s a sealed up fireplace (not very deep). The chimney has been capped and there’s no ventilation as they installed a sold cast iron block - I’ll attach pictures. From the new plaster down it is very damp with the metal edging on the walls rusty. I opened up the metal seal - the cavity was filled with dead bees - millions of them! I need advice! Should there be a ventilation plate put in or do I need to do something else as I need to sort this damp issue out. Thanks in advance for any help
You need a through air flow, a cowl rather than capped off. Could well be other issues, whats on the other side of the chimney breast, is it watertight, condition of pointing/render etc.