Can an impregnator (impregnating sealer) be used to waterproof stone?
Estimated Reading Time: 2 MinutesQ. Can an impregnator be used to waterproof stone?
A. Not exactly. An impregnator will make the stone water resistant, but it will not make it waterproof.
Impregnating sealers are designed to penetrate the surface and fill the microscopic pores within the stone. This reduces the stone’s absorbency and helps repel water, oils, and other staining agents. Basically, it buys time for people to wipe up spills before they get absorbed and potentially become difficult-to-remove stains. Impregnating sealers do not completely seal the pores. Moisture and vapors can still pass through the surface of stone to a certain extent, which is why impregnators are referred to as breathable sealers.
Water resistance is typically sufficient for most indoor and outdoor applications, as it protects the stone while allowing it to breathe — a crucial factor for natural stone longevity and appearance. Over-sealing or using non-breathable coatings can sometimes lead to issues like trapped moisture, which may cause efflorescence or spalling over time.
When true waterproofing is required, for example, in areas that are submerged or exposed to constant water saturation, a topical coating or membrane that creates a complete barrier on the surface can be used. These coatings are typically film-forming and non-breathable, offering full protection against water penetration. Note that topical coatings or membranes may alter the appearance of the stone (e.g., adding a sheen or changing color) and can require more frequent maintenance to avoid some of the problems mentioned in the previous paragraph.
Because different types of stone have varying porosity, durability, and finishes, it's important to select the correct sealing or waterproofing method for your particular stone. A reputable and experienced stone restoration professional can assess the specific type of stone and its environment to determine the most effective and safe treatment. To find a vetted PRO in your area, visit www.surfacecarepros.com and click on Find a PRO.
ABOUT THE AUTHOR Fred Hueston is the Chief Technical Director at SurfaceCarePROS.com and Director at StoneForensics.com. He is also the author of Stone and Tile Restoration: The Manual, a comprehensive online manual for stone and tile restoration contractors. [Learn more about Fred.]