Seal-Krete Original Waterproofing Primer/Sealer protects vertical concrete and masonry against the damaging effects of moisture penetration. It penetrates deeply into concrete pores, binding sand and cement particles to form a tough, flexible, breathable film. Original is excellent for binding chalky surfaces to improve paint adhesion on all painted and unpainted substrates including concrete block, stucco, aluminum siding, drywall and plaster. It strengthens mortar joints, reduces efflorescence on brick and rejuvenates color on older painted surfaces like aged vinyl siding and stucco.