Painted Chimneys

Although painting of older brick chimneys is common in-home remodels, this practice is not recommended by most masonry and chimney contractors.

Brick is porous and naturally absorbs moisture. Painting the brick can trap moisture inside, leading to potential issues like peeling paint, efflorescence (white, powdery deposits on the surface), and even structural damage as the trapped moisture can freeze and expand (spalling). Bricks need to breathe to release moisture that naturally accumulates. Paint can block this breathability, causing a buildup of moisture within the brickwork, which can degrade the masonry over time. Once painted, the brick surface requires regular maintenance. If the paint begins to peel or crack, it can be difficult and labor-intensive to repair, often necessitating complete repainting or even stripping of the old paint. Painting can alter the natural appearance of the brick. If the paint fades or changes color over time, it might not be easy to match or update, impacting the overall look of the property. If the brickwork has existing issues like cracks or damage, painting over it can mask these problems rather than addressing them, potentially leading to more significant issues down the line. If you’re looking to enhance or protect your brick chimney, it’s often better to consider alternatives like a masonry sealer that allows the brick to breathe while providing some level of protection against moisture.

Painting a brick chimney can increase the risk of spalling. Spalling occurs when the surface of the brick or mortar flakes off or crumbles, typically due to the expansion and contraction caused by moisture infiltration and freeze-thaw cycles. As moisture is retained within the brick due to the inability of the brick to breathe properly, the moisture can freeze and expand. Expansion of moisture within porous brick will result in displacement of the brick composition and can result in spalling and damage. To minimize the risk of spalling, it’s generally better to use a breathable masonry sealer designed for bricks. These sealers help protect against moisture while allowing the brick to continue breathing, reducing the likelihood of spalling and other moisture-related issues.

Unfortunately once the brick has been painted, the best method of repair is to maintain the paint layers as best as possible to prevent moisture from getting trapped between the layer of paint and brick chimney. Removal of paint at porous brick is extremely difficult and typically unsuccessful. Small remnants of paint will remain within the crevices and pores of the brick and mortar. Physically scouring the brick or use of harmful chemicals can destroy the brick permanently and is not recommended. It is important to note that often the brick may be painted, but the crown is left unpainted and porous. Water will seep through the chimney crown and into the brick below. Sealing the chimney crown is also essential in maintaining a waterproof seal on an already painted brick chimney.

If you are looking to change the color of your chimney the best option is to use a masonry sealer which comes in a number of colors. A masonry sealer is a protective coating designed to be applied to masonry surfaces such as brick, stone, concrete, and stucco. Its primary purpose is to enhance the durability and longevity of these surfaces by providing a barrier against moisture, stains, and environmental damage. The surface should be clean, dry, and free of any contaminants before applying the sealer. For surfaces that need to remain breathable, choose a penetrating sealer. Film-forming sealers may not be suitable if moisture needs to escape from the surface. Depending on the type of sealer, you may need to reapply it periodically to maintain its protective qualities. Using a masonry sealer is a good practice to protect your brick or stone surfaces from moisture damage while preserving their natural appearance and extending their lifespan.