Because chimneys extend so far above the roofline, they are especially prone to damage from the elements. Once brick start to crack or spall, the integrity of the chimney goes downhill pretty quickly. Preventative maintenance is crucial to lengthening the life of your chimney. Water is the main cause of most cracks in your chimney and is the cause of the face of your brick popping off and falling onto the roof. Prevent costly repairs of rebuilding the chimney or repairing brick by using a water repellent regularly.
ChimneySaver Water-Base Water Repellent has been in circulation by professionals for almost 20 years. This unique repellent is vapor permeable so it will not trap water vapors in the brick. Water repellents that trap the vapors in the brick actually cause spalling rather than preventing it. The Water-Base formula from ChimneySaver is specially formulated for chimneys that have never been treated with another waterproofing product. If you have used a different kind of water repellent previously on your chimney, we recommend using the Solvent-Base water repellent, with mineral spirits.
It is important to remember that there is always a certain, small percentage of moisture present in masonry surfaces or concrete, and film-forming sealers use silicone to coat the brick complete, trapping those vapors inside and catalyzing the rate at which brick spall and crack when the vapors cannot escape. This is the opposite effect of what a protective water repellent should do. Film forming water repellents will contribute to the rate at which the brick or concrete on your chimney or other masonry project deteriorates and heighten freeze-thaw damage.
In contrast to these film-formers is the ChimneySaver Water Repellent products. Both the Water-Base and the Solvent-Base make it possible for vapors to escape, preventing the deterioration of the masonry surface. Per gallon, the ChimneySaver Water-Base Water Repellent covers between 90 and 150 sq. ft. depending on the thickness of each coat, and it is available in 3 and 5 gallon containers. When applying this product it is important to make sure that the temperature outside is above 40 degrees Fahrenheit so that it can cure properly, and you must allow six hours of drying time before a rainfall even though the product itself has a dry time of one to two hours. Very cold temperatures will reduce the efficiency of this breathable water repellent. It is recommended to apply using a pump-sprayer, and soap and water is appropriate for clean up.