The Differences Between Latex Block Fillers and Masonry Waterproofers

Description

• Latex block fillers are a paint product that dries to an opaque or pigmented skin that seals the surface of the concrete, preventing both water and water vapor from passing through. A concrete waterproofer is not a sealer. It is a breathable coating that penetrates into the concrete, but does not seal it. Concrete waterproofers are invisible once dry and contain silicone in one of three forms: silanes, siloxanes or room-temperature vulcanizing silicone rubber.

Moisture and Masonry

• Concrete and other concrete surfaces such as brick are porous materials. Water and water vapor enters, filling the tiny pores. This can cause the masonry to expand, and as it leaves, the masonry contracts, possibly resulting in cracks, crumpling and other structural issues. Paint or block fillers can trap moisture inside the substrate, and because they dry to an impermeable skin, the water cannot leave. For this reason, these products should never be used as a waterproofer. Masonry waterproofers allow the vapor to leave while repelling water, which prevents damage to your masonry structures and surfaces.

Recommended Uses

• Latex block fillers are not designed for use as a waterproof sealer. Although they may help limit the penetration of water through your masonry, they will not protect it and are not intended to do so. Instead, these products are meant to fill gaps, cracks and other surface imperfections to prepare masonry for a finish coating of paint or another type of decorative coating. Latex block fillers do not allow water vapor to enter and leave the masonry so it becomes trapped inside the substrate and this can lead to cracks. Masonry waterproofers, on the other hand, are formulated to seal or repel moisture, using a breathable layer of protection that allows vapor release. They are not intended for decorative use and in most cases typically do not change the appearance of the masonry surface.

Application

• Masonry waterproofers and latex block fillers are both typically brushed or rolled on the substrate. Waterproofing products must be applied to a clean, unpainted surface to penetrate into the pores of the concrete. Latex block fillers also require a clean surface that is free of chipped or peeling paint to ensure a proper coating that will not crack or bubble. Both typically require two or more coats. When applying latex block filler to interior masonry surfaces, a concrete waterproofer should be applied to the exterior side to prevent water from gathering within the concrete but allowing vapor to pass in and out. It is not recommended to use block fillers on both the interior and exterior of any concrete surface.