How To Caulk Concrete Cracks Using Sikaflex 15LM Sealant

Over time, cracks can appear in concrete as a result of a variety of reasons. They can look unsightly and if left untreated, they can cause major problems that are expensive and time-consuming to fix. Here are a couple of ways in which you can caulk concrete cracks found in garage floors, driveways, sidewalks, patios, and other concrete surfaces around your house. For safety, please put on gloves and eye protection tools whenever you repair concrete.

Why Cracks Appear in Concrete

Cracks can appear in concrete due to various reasons. One of the reasons is due to the forces applied to the tensile, structure, shear or compressive forces to the concrete. These forces cause deformation which in turn lead to cracks forming. Cracks can also be caused by hydraulic shrinkage as the water contained in the concrete evaporates. Thermal shrinkage is another cause of cracks in concrete. This is usually for large structures. Whenever there is an exothermic reaction in concrete, heat is produced which dissipates over time. This changes in temperate cause differential deformation that leads to cracks. Swelling may also cause cracks to form in concrete. Concrete may swell because of sulfates from the earth that come into contact with the concrete.

Small Cracks

  • Clean Them Out – Make use of a wire or stiff bristle brush to get rid of loose debris. You may also make use of a leaf blower.
  • Apple Sealant – Fill out the gaps and narrow cracks using a concrete caulk and a caulk gun. This is paintable and waterproof while also being textured so it will blend nicely with the concrete. This also prevents cracking or loss of adhesion.
  • Proper Tool – by using a wet margin trowel or flexible putty knife, tool the sealant right after application if you think it needs leveling and smoothing. If the area is exposed to the elements, place a plastic sheet loosely over it for a day so it will stay dry.

Large Cracks

  • Clean Them Out – Make use of a wire or stiff bristle brush to get rid of loose debris. You may also make use of a leaf blower.
  • Clean Surrounding Areas – Scrub off any grease or oil surrounding the repair area and rough it up by using a solvent like mineral spirits and a stiff bristle brush.
  • Apply Patching Material – Use a concrete patch to fill in the repair area. It will resist grease, oil, and salt and will dry to a concrete-gray color. You can also use it to glue together broken concrete pieces or to patch holes. Take a flexible putty knife or trowel and position it into place. This will also remove any air in the cracks. On the surrounding surface, feather the edges. If the area to be repaired is more than 1/2 inch deep, patch it in 1/4 layers to a maximum depth of 1 inch. Allow each layer to dry before the next application. If needed, you can paint the patched areas with latex paint roughly 2 to 4 hours.