The Best Way to Clean Indoor and Exterior Concrete Floors

How to Clean Concrete Floors

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While concrete was once relegated to sidewalks, basements, and garages, it has moved indoors to become sophisticated floors and countertops. Concrete is exceptionally durable and easy care if you treat it properly.

There are several types of concrete finishes:

  • Unsealed: Poured concrete without any additional treatment is unsealed. This leaves the surface naturally porous and susceptible to stains, particularly liquid stains like oil.
  • Sealed: Sealed concrete is coated with acrylic resins, penetrating silicates, epoxies, or urethanes making it nonporous and stain-resistant.
  • Polished: Concrete can be polished wet or dry to a glossy finish that never needs to be waxed or recoated. The level of sheen can be chosen, and the concrete can be stained to look like marble, granite, or any polished stone
  • Stained: If grey isn't your favorite color, there are stains in a wide range of colors to color newly poured or older concrete. The stains penetrate the concrete and are permanent. The finish can then be sealed or left unsealed.
  • Stamped: Often called imprinted or textured concrete, stamped concrete can replicate stone, brick or even wood. The concrete is usually stained and can be left unsealed or sealed to make it more durable.
  • Painted: While concrete accepts stains readily, it is more difficult to achieve a durable surface with oil-based or latex paint. If the surface has been polished or sealed, the paint will not adhere properly, and peeling will occur.

    Cleaning Unsealed Concrete Floors or Exterior Concrete

    Even though it is easy-care, garage floors, sidewalks, and patios will look better with a good cleaning. Start by removing anything sitting on the concrete. Sweep away debris and dirt with a stiff-bristled broom or use a shop vac.

    Now it's time to tackle the stains on the concrete:

    • Grease Stains: Sprinkle the stained area with a layer of cornstarch or dry kitty litter. Let it remain on the stain for at least three days to absorb the oil. It takes that long because unsealed concrete is porous and the oil goes very deep. Vacuum away. Repeat if needed.
    • Food or Beverage Stains: Mix two tablespoons of dishwashing soap with one quart of water. Using a stiff brush, apply the mixture and scrub well. If the stain is oily, apply the soap directly onto the stain and scrub. Rinse well with plain water.
    • Tire Marks: Wet the area first and spread a degreaser over the stains. Let the cleaner work for at least four hours and then scrub with a stiff brush. Rinse well.
    • Rust Stains: If the stains are light, pour distilled white vinegar on the stains and let it work for at least 30 minutes and then scrub with a stiff brush and rinse. If the stains are large and dark, use a commercial rust remover that contains oxalic acid.
    • Mildew Stains: Wearing rubber gloves, mix two tablespoons powdered laundry detergent, two tablespoons trisodium phosphate (TSP), and one-quart water. Scrub the mildewed area with a stiff brush and rinse well. If the mildew is extremely heavy, use a chlorine bleach and water solution instead. Mix one cup of bleach per gallon of water and scrub the area with a stiff brush and then rinse well. NOTE: Do not mix bleach with other cleaners and protect shrubs and grass from the mixture. Wear protective clothing and use only in a well-ventilated space.

      The easiest way to clean exterior concrete is with a pressure washer filled with a solution of trisodium phosphate and water. If you don't have one, wet the concrete with a garden hose and use a stiff bristled brush like push broom to distribute the trisodium phosphate and scrub away. Complete the cleaning with a good rinse and allow the area to air dry.

      Cleaning Sealed Concrete Floors

      Since sealed concrete floors are nonporous, they are resistant to most stains making cleaning very simple. Sweep, vacuum or dust mop regularly to help prevent scratches from dirt and grit. Weekly, mop with just a bit of dishwashing liquid and warm water to remove stains, rinse with clean water, and allow to air dry.

      Do not use harsh cleaners, which can break down and dull the sealant. Reseal as recommended by the installer.

      Cleaning Polished Concrete Floors

      Polished concrete is the easiest care concrete because it never needs to be resealed. Simply dry dust mop regularly. When soiled with dirt or spills, damp mop with a commercial polished concrete cleaner that is pH-neutral.

      Cleaning Painted Concrete Floors

      Painted concrete floors are cleaned in much the same way as other finishes. However, since the surface can be sealed or unsealed, it is important to avoid harsh or acidic cleaners that may damage the finish. After sweeping and dusting, use a mild all-purpose cleaner and a damp microfiber mop. Do not use excessive moisture because that can break down the paint and cause it to peel.

      Always rinse well with a mop dampened with plain water to remove any soapy residue and allow the floor to air dry.