Repairing chips, spalls, and cracks

Source:www.stonediamondtool.com Date:2018/2/9 Read:518

When making repairs to the concrete before polishing, your goal is to blend the fix as closely to the surrounding concrete as possible. To get the best results, you must use specific products for specific repairs.

For chips left behind from carpet tack strips, small divots and spalls, you can choose from a variety of different cement-based patching compounds, depending on the depth and severity of the affected area. Keep in mind, though, that even the best patch may not be an identical match to the rest of the polished floor. If you are repairing colored concrete, use a patching product that can be tinted to match the desired color.

For minor flaws no deeper than 1/8 inch, try using a traditional skim-coat material used for overlaying concrete floors. For deeper flaws (1/4 inch or greater), use anchoring, or hydraulic, cement as a patching compound or even a self-leveling overlay if the flaws cover a large area.

When dealing with cracks, you first need to determine if they are static or moving cracks. Static cracks (sometimes called “craze cracks”) are hairline flaws that only affect the surface of the concrete. Generally, this type of crack requires little if any attention and can actually add decorative interest once the floor is colored and polished. If you want to disguise the cracks, an effective method is to apply a tinted urethane as a skim coat.

Moving cracks, also called “active cracks,” are more serious and typically must be repaired before you start polishing by crack chasing, cleaning, and filling. Crack chasing involves using a V-grooved diamond blade attached to an angle grinder or a walk-behind machine specifically designed to route out the crack. Next, thoroughly clean out the crack by removing all debris with a shop vac and then blow away any remaining dust with compressed air. To fill the routed crack, use a semi-rigid polyurea, which you can have color-matched to the floor, or apply a grind-and-fill repair material before polishing.