Krystol Mortar Admixture™ (KMA)

Protecting Rendering & Plastering Mortar


Krystol Mortar Admixture (KMA) is a chemical admixture in dry powdered form which is specifically formulated to provide long-term protection in concrete masonry units, masonry mortar, and rendering/ plastering mortar. KMA is used in place of externally applied surface membranes and sealers to protect against water and waterborne contaminants and can be easily incorporated into the existing mix design and application processes.



Read the Material Safety Data Sheet (MSDS) for this product. For professional use only. KMA becomes caustic when mixed with water or perspiration. Avoid contact with skin or eyes. Avoid breathing dust. Wear long sleeves, safety goggles and impervious gloves.


  1. Before application of the rendering, the surface must be clean and free of dirt, oil, or other elements which may interfere with bonding.
  2. Smooth or non-absorbent surfaces should be prepared with one of the following methods:
    a. Sandblasting, wire brushing, acid etching, or chipping, or
    b. Application of a dash-bond coat (1 part cement and not more than 2 parts aggregate) applied forcefully against the surface, left untrowelled, undisturbed, and moist cured for at least 24 hours, or
    c. Application of a bonding compound.
  3. It is strongly recommended that the surfaces be dampened with clean water prior to applying the rendering for improved performance in adhesion, durability, and reduced cracking


AI6-21bTIP: Before opening the pail, loosen compacted material by turning the pail over three or four times.

  1. Dose KMA at 2% by weight of cement. When dosing on the jobsite, measure and add 1 liter (1 quart) of tightly-packed KMA for each 40 kg (88 lb.) bag of cement in your mortar mix. Mix well. Reduce water if necessary.
  2. Install mortar as normal.
  3. Protect and cure application following mortar manufacturer’s instructions. Krystol products must be protected from rapid drying and kept damp to develop their full properties. Cover the repair with plastic sheeting or damp burlap to contain moisture. After the repair has hardened, mist the surface with water to maintain moisture levels for 48 hours.
  4. Store any unused portions in an airtight container to prevent moisture contamination.