Krystol Mortar Admixture™ (KMA)

Protecting Masonry 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.


KMA-DosageTIP: 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. Store any unused portions in an airtight container to prevent moisture contamination.


TIP: Test batches are highly recommended to assess local plastic and hardened properties, and determine appropriate mix designs.

  1. KMA can be added at any time during your batching process. However, the plastic properties may vary with the time of addition depending on the mix proportions and site conditions. Refer to ASTM C270 (Standard Specification for Mortar for Unit Masonry) for a typical mixing sequence. Adjust the mixing sequence as necessary to optimize the mix for your application.
    TIP: For consistency in field mixing, the materials should always be added to the mechanical mixer in the same order and in the same amount.
  2. Most KMA mixes will require less water than normal. Reduce mixing water as needed to obtain desired consistency.
  3. Once all materials are added to the mixer, mixing should continue on medium/high speed for at least an additional 2 minutes. When the right consistency is achieved, the mortar should stick to the trowel when it is picked up, and should slide off the trowel easily as it is spread.
  4. Install mortar as normal.
  5. 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.