How to Seal a Stucco Finish

Stucco finish is used on both interior and exterior walls. This porous product requires a sealant to protect it from damage caused by moisture and mildew.

Step 1 – Washing the Stucco

Use a garden hose to wash the stucco surface. Be sure to start at the top and work down to the bottom. Pour a gallon of warm water into a large bucket. Add one teaspoon of trisodium phosphate to the water. Immerse a sponge into the cleaning solution. Use the sponge to clean any residue that is stuck to the stucco. Be careful not to accidentally damage the texture.

Step 2 – Taping the Stucco Area

Tape around the edges of the stucco wall with painter's tape. Wrap tape around any pipes or other objects protruding from the wall.

Step 3 – Mixing the Paint

Read the instructions provided by the manufacturer of the waterproof paint before you begin. Use a paint stick to carefully combine the waterproof paint. Continue mixing the contents of the can until the paint is uniform in color and consistency. Be sure to mix in the paint on the bottom and sides of the can.

Step 4 – Cutting In the Waterproof Paint

Apply a band of waterproof paint around the edges of the stucco. The band should be about four inches wide and follow the lines of the painter's tape. You should also paint around the protruding objects.

Step 5 – Applying the Paint to the Remaining Stucco

Pour waterproof paint into your paint tray. Immerse the paint roller into the paint. Be sure to use a roller with a thick nap. Use the roller to apply the paint to the stucco finish. Begin at one corner of the area. Use long, even strokes to apply the paint. Be sure to use enough pressure on the roller to force the paint into all of the stucco areas. Allow the paint enough time to dry completely. Apply a second coat of the waterproof paint to the stucco. Allow the second coat to dry thoroughly as well.

Step 6 – Applying the Sealer

Use the paint roller to apply the sealant to the stucco. Be sure to read the instructions provided by the manufacturer of the sealant before you begin. Begin at the top of the surface, and work your way downward. Apply the sealant in long, even strokes, forcing it into the textured stucco. Allow the sealant to dry completely. Apply a second coat of sealant, and allow it to dry thoroughly.

Step 7 – Removing the Tape

Carefully remove the painters' tape from the edge of the stucco surface. Be sure not damage the stucco by accidentally pulling off any of the surface.