How to use sikaflex concrete repair

Updated February 21, 2017

Sikaflex concrete fix is a Sika trademarked product used to repair cracks in concrete. The product is an elastomeric sealant designed to provide a flexible seal within the concrete fracture. Concrete usually cracks due to freezing weather conditions where water penetrates the concrete substrate and ice expansion occurs. The expanding ice splits the concrete surface and requires a repair to prevent further damage. Sikaflex concrete fix is suitable for use in concrete cracks between 1/4 and 1/2 inch wide, as recommended by Sika.

Use a hand brush to sweep any loose concrete crumbs out of the floor-, ceiling- or wall-based concrete crack. Use a vacuum cleaner with a slim utility tool to remove concrete dust particles from the crack.

Spray a water-based degreaser into the crack to break down any oil, dirt or grease marks. Scrub the base, walls and surface of the crack with a small brush to help lift any dirty stains. Rinse the degreaser and dirt out of the crack with water and allow the clean concrete crack to dry.

Measure the width and depth of the crack with a ruler to check that the dimensions are within the Sikaflex parameters. Insert a closed-cell backer rod in a concrete floor crack that's deeper than 1/2 inch, and provide a maximum sealant depth of 1/2 inch. Ensure a maximum sealant depth of between 1/4 inch and 1/2 inch for walls and ceilings.

Apply the Sikaflex concrete fix sealant into the base of the crack with a caulking gun. Fill the crack, keeping the Sikaflex nozzle in constant contact with the sealant to keep air out of the repair work.

Smooth the surface of the crack repair with a damp cloth or by using your gloved finger. Allow the Sikaflex concrete fix to cure for seven days before applying paint or covering the repair with water.


Acclimatise the Sikaflex to 21.1 degrees Celsius for optimum application performance in an ambient temperature of between 4.44 and 37.8 degrees Celsius, as recommended by Sika. Use an additional Sika sealant primer for underwater crack repairs.


Wear a respirator, protective gloves and safety goggles to prevent ingesting harmful chemical irritants.

Things You'll Need

  • Hand brush
  • Vacuum cleaner
  • Vacuum cleaner utility tool
  • Water-based degreaser
  • Small brush
  • Ruler
  • Closed-cell backer rod
  • Caulking gun
  • Cloth
  • Sika sealant primer
  • Respirator
  • Protective gloves
  • Safety goggles
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About the Author

Residing in the coastal county of Devon, England, Jane Humphries has been writing since 2004. Writing for "British Mensa" nationally and regionally, Humphries has also held key roles within the High IQ Society. She received a Bachelor of Science, honors, in psychology with combined studies covering biology, statistics, economics, politics and sociology.