Chimney cracks are very dangerous. What starts out as a hairline crack will continue to grow from freeze and thaw damage and deepen and widen until what you are left with is a very serious masonry problem. Whether the cracks appear on your brick chimney or on other parts of your home, CrackMagik is a product that has been tested and true. CrackMagik is unique in that it can be used to waterproof cracks up to 1/8″ wide. Cracks much larger than that are probably going to require some rebuilding or tuckpointing of the chimney or other brick area. This chimney crack repair product is what I send my masonry crew out with.
Over the years I have found that using CrackMagik directly over the cracks on the masonry surface, allowing it to cure, and using
ChimneySaver Water Repellent over the crack and the surrounding area produces a very water tight
seal. This type of repair is ideal if you are having a leak and are trying to solve the water issue. Instead of rebuilding the entire suspected masonry area, this less expensive repair (CrackMagik and ChimneySaver Water Repellent Application) can help you identify if a crack in the masonry is indeed the offending part of the home or if you need to dig deeper for an answer by assessing the roof or the flashing on the chimney. Brick chimney repair is expensive and going with the least expensive repair first is encouraged.
When applied by a professional the CrackMagik product comes with a 10 year warranty. The product carries no warranty if you make it a do it yourself job. This breathable formula will not trap water that is found naturally in the masonry but will prevent water from actually entering the masonry. CrackMagik is applied with a small brush directly on the crack to seal it and takes a few hours to dry. This product is a paintable caulk and it dries to a milky white color but does not significantly change the color of the chimney or other masonry surface. Each half gallon container of CrackMagik covers approximately 100 sq. ft. of wall space and should be applied in temperatures between 40 and 100 degrees Fahrenheit.