What Is the Preparation for Walls Before You Use Drylok Paint?

Determing the Type of Moisture Damage

• Whereas Drylok is a suitable remedy for seepage, Drylok's manufacturers recommend using a dehumidifier to address condensation. Drylok's manufacturers recommend a simple test to determine whether your wall's moistness results from exterior seepage or interior condensation. To perform the test, affix a one-foot square piece of foil to the wet wall; use tape to completely seal all of the foil's edges. Inspect the foil after a few days. If the foil's interior face is wet, your wall is seeping. If the foil's exterior face is wet, your wall is wet because of interior condensation.

Cleaning the Wall

• Thorough cleaning ensures that Drylok properly adheres to a masonry surface. Stiff-bristled wire brushes effectively remove loose mortar, concrete and existing surface coatings, such as paint. Importantly, Drylok's manufacturers advise installers to fully remove old paint prior to applying Drylok. In addition to manual brushing, do-it-yourselfers strip and clean masonry walls with power tools, such as drill and grinder wire wheels or sandblasters.

Etching the Wall

• Chemical etching controls efflorescence, a white, scaly build-up that results from seepage. If your wall shows signs of efflorescence, you must treat the problem before applying Drylok or alternative masonry waterproofing compounds. Composed of strong acids, chemical etching compounds dissolve and remove buildup. After spraying a wall with etching compound, installers rinse the surface and allow the wall to dry.

Repairing Surface Damage

• After cleaning and etching, installers must repair cracks and holes with repair mortar or hydraulic cement. Hydraulic cement is a specialized mortar mix that hardens under wet conditions. Thus, standard repair mortar is suitable for repairing dry surfaces and hydraulic cement is suitable for patching actively seeping surfaces. Before applying and smoothing repair compounds, installers should chisel gouges to create convex holes. In other words, the finished hole should be wider toward the wall's exterior. While a convex shape naturally holds repair compound in position, a concave shape allows repair compound to easily drip out of place.