No water repellent can stop water from penetrating small holes and visible cracks, and because nearly every chimney has them, we developed Crack and Joint Sealant — a unique, breathable, silicone elastomer. Think of it as a paintable caulk. Use it for sealing minor cracks (up to 1/8”) and defects in mortar joints where the mortar and chimney are otherwise sound. This allows you to easily correct these defects without the time and expense of tuckpointing.
For best results, use Crack and Joint Sealant after a ChimneySaver treatment. If using ChimneySaver Water-Base, Crack and Joint Sealant can be applied immediately following application while the chimney is still damp. If using ChimneySaver Solvent-Base, allow it to dry completely before applying Crack and Joint Sealant. Crack and Joint Sealant dries in about six hours to a cloudy (milky white) film that will not significantly change the chimney’s appearance.