Sikaflex+ Self-Leveling Sealant is a candidate for suitable horizontal concrete joints, not a universal crack repair. The self-leveling behavior is useful in a contained, level joint but makes it the wrong choice for a vertical gap or a sloping run where the material can flow away.
This review uses the product data sheet rather than a hands-on adhesion or durability test. Different Sikaflex products have different permitted substrates; the brand name alone is not enough to choose a cartridge.
Match the joint to this formulation
The Sikaflex+ data sheet identifies horizontal concrete and cementitious slab applications. It excludes sloped surfaces and asphalt or bituminous substrates. Do not transfer an asphalt claim from another Sika formulation to this one.
Its stated joint limits include a maximum width of 1-1/2 inches and maximum depth of 1/2 inch, with minimum width and depth of 1/4 inch. Joint design, movement and traffic requirements also matter. Use the current sheet for the required geometry and backing rather than simply filling a deep void to the bottom.
For example, a contained horizontal expansion joint is a different problem from broken concrete with a widening, uneven edge. Sealant cannot restore missing load-bearing concrete or correct settlement. Investigate movement and water entry before deciding that a flexible seal is the repair.
Preparation determines whether it is a sensible job
The joint faces must be sound and prepared as specified. Remove unsuitable old material and contamination; use compatible backing or a bond breaker where required so the sealant can move as intended. A surface that looks clean from above may still have loose material on the sides.
Protect nearby finishes and contain open ends before application. Estimate the quantity from the prepared joint dimensions. Buying by the visible crack length alone overlooks the volume below the surface.
Plan the curing window
The sheet gives a typical final cure of three to five days, with conditions affecting timing; tack-free is not the same as fully cured. It also specifies a longer waiting period for painting or total water immersion. Check those instructions for the intended finish and exposure before scheduling use of the area.
An opened cartridge is not a reason to rush unsuitable work or use the remainder on unrelated gaps. The product instructions call for using opened cartridges the same day.
Verdict
Choose the exact Sikaflex+ self-leveling formulation when the substrate, horizontal geometry and preparation requirements match. Choose a suitable non-sag or other specified repair material for a different joint. If the concrete is moving unexpectedly, displaced or structurally damaged, diagnosing that problem has more value than buying another tube.