How to Waterproof Stucco

Emily Patterson

Stucco is used in a variety of settings. Interior stucco often decorates a wall while exterior stucco is a common finish for concrete block or even the entire exterior of the house.

Waterproof stucco with a masonry waterproofing paint or sealant to reduce erosion from moisture.

If the stucco is in a location where moisture will build up behind the stucco after waterproofing, such as a damp basement, the stucco will eventually chip and fall off the surface. Be sure to correct moisture problems behind the stucco before waterproofing.

  1. Secure painter’s tape around all edges or protrusions of the stucco. For example, if the stucco is against siding, place painter’s tape at the edge of the siding where it meets the stucco surface.

  2. Stir the masonry waterproofing paint or sealant with a paint stir stick until the color and consistency are uniform. Scrape the bottom and sides thoroughly.

  3. Paint the edges of the stucco and around any protrusions in the stucco wall with a paintbrush. Create a band that is approximately 3 to 4 inches wide around the edges.

  4. Fill the paint tray's well with the masonry waterproofing paint or sealant.

  5. Place a thick-napped roller cover on a paint roller. Roll the paint roller into the masonry paint or sealant to wet it all the way around the roller.

  6. Start from one side of the stucco surface and roll the paint or sealant onto the stucco. Pay attention to surfaces that are high or shallow to be sure the paint or sealant has coated the entire surface.

  7. Apply a second coat if recommended by the manufacturer. Allow it to dry according to manufacturer’s specifications before applying a second coat of waterproofing paint or sealant to the stucco.

  8. Remove the painter’s tape from surrounding edges when the masonry waterproofing paint or sealant is dry.

  9. Tip

    Go around the edges of exterior stucco with an exterior-grade caulk to seal the edges and prevent moisture from getting behind the stucco.


    Use waterproofing paint in areas with adequate ventilation. Follow all manufacturer-recommended safety precautions printed on the product label.