The first step in resolving damp issues is to identify and repair any leaks. Common sources include faulty flashings, pointing, and open chimney pots. Once these are rectified make sure the stack is ventilated adequately.

Chimneys require proper ventilation, even if they are no longer in use.  Most chimney related issues stem from moisture, which is directly linked to inadequate airflow.  When there is insufficient circulation within the chimney, moisture becomes trapped, leading to potential problems.

A contemporary solution involves replastering the affected walls using sand-and-cement plasters topped with a gypsum finish. Many builders prefer these modern materials for their durability against salt effects. However, it’s essential to recognise that cement is non-breathable, which may lead to moisture buildup within the masonry, potentially resulting in long-term damp issues, particularly in older buildings.

For a more effective remedy, consider using specialised lime plasters with salt-inhibiting properties, such as Roman mortars. These plasters are made from lime and volcanic materials, mixed at room temperature without heat. The pre-burnt volcanic sands and ashes create an open pore structure that enhances breathability. This unique composition boosts the plaster’s resistance to dampness and salts, making Roman mortars particularly effective in humid and salty environments.

For historic masonry, poultices can be employed to efficiently extract soluble salts. A poultice mixture is applied to the affected surface, where it absorbs the salts and prevents crystallisation. After allowing the poultice to dry, it is removed, taking the salts with it. This process may need to be repeated multiple times before applying lime plaster to ensure the wall is adequately prepared.

To further protect the chimney breast from dampness, various isolation techniques can be utilised. Methods such as lath and plaster or the use of metal or timber stud work can serve as effective barriers, preventing moisture from reaching the plaster.