Waterproofing A Masonry Chimney

Among the myths that abound regarding chimneys is the notion that a masonry structure is waterproof. While it is true that bricks and mortar are sturdy and durable when properly put together, they are also susceptible to damage from water penetration.

Bricks and mortar readily absorb water, but release it more slowly. Over time, water washes away elements of the mortar, weakening it. Mold, moss and other vegetation grows on damp brick and mortar, their tiny root systems tearing at the mortar joints. Water freezes and thaws inside the mortar joints and bricks, causing cracks to widen and brick surfaces to spall. Eventually crevices in the mortar are large enough to catch seeds carried by the wind or birds. The larger root systems of these plants damage the masonry structure more rapidly.

In Upstate South Carolina, water damage is visible on most masonry structures after only a few years. Chimneys are particularly susceptible to water damage as they are exposed to the wind and weather above the roof. Water damage is slow, but it will inevitably destroy your masonry chimney from the top down.

Proper construction and maintenance of masonry structures can prevent water damage. Regular chimney inspections can alert you to problems in your chimney system and give you time to correct them before they become serious and expensive problems.

Click on the images above to see how we correct the common chimney defects that lead to water damage.