Damp problems with Chimney Stacks
In the past few years in London and surrounding counties, we have experienced an increase in calls concerning dampness to internal chimney breasts. Chimney stacks are open to the elements and should the chimney stack not be correctly maintained, defects like damp can occur. The main causes of damp in chimneys are rain, condensation or salt contamination. Salt contamination especially in older chimney breasts is a common problem and is usually a result of fossil fuels like coal being burnt in the fire place. Because coal comes from the ground it can contain salt minerals like nitrates, chlorides, sulphates etc. When the coal is burnt these salts manifest themselves in the brickwork of the fireplace. Over a period of time and especially if the fireplace is no longer used as such the salts can migrate from the brickwork and settle in the wall plaster. These salts then become what is technically known as hygroscopic, which means that they can attract and hold atmospheric moisture fro...