Garage Floor Cleaner

Steps

1. Sweep the garage floor thoroughly to remove loose dirt, dust, and debris.
2. Pre-treat oil stains: Sprinkle 1/2 cup of baking soda directly onto any visible oil or grease spots. Let it sit for 15 minutes to absorb the oil, then sweep it up.
3. In a large bucket, dissolve 1/2 cup of washing soda in 1 gallon of hot water. Stir until fully dissolved.
4. Add 2 tablespoons of liquid castile soap to the bucket and stir gently to combine without creating excessive foam.
5. Pour the solution directly onto the garage floor in sections, working from the back of the garage toward the door.
6. Scrub each section with a stiff-bristled push broom or deck brush, applying firm pressure on stained areas.
7. Let the solution sit on the floor for 5 to 10 minutes on heavily soiled areas before scrubbing again.
8. Rinse the floor with a garden hose, directing the water out through the garage opening. For best results, use a hose nozzle with moderate pressure.

Why It Works

Washing soda (sodium carbonate) is a strong alkaline cleaner with a pH of around 11. At this pH, it saponifies oil and grease — meaning it reacts with the fatty acids in oil to create a crude soap that washes away with water. This is far more effective against automotive fluids than the weaker baking soda (pH 8.3). Castile soap acts as a surfactant, reducing the surface tension of water so the cleaning solution can penetrate into the pores of concrete rather than beading up on the surface. The pre-treatment with baking soda absorbs the top layer of fresh oil, preventing it from spreading during the wet cleaning phase.

Alternative

• For a spot-treatment approach, make a thick paste of washing soda and water. Apply it directly to oil stains, cover with plastic wrap, and leave overnight. Scrub and rinse in the morning.
• Trisodium phosphate (TSP) is a stronger alternative for extremely heavy grease. Mix 1/2 cup TSP per gallon of hot water. TSP is harsher, so wear gloves and safety glasses, and rinse thoroughly.

Tips

• For fresh oil spills, cover them immediately with cat litter, sawdust, or baking soda. Let it absorb for several hours or overnight before sweeping up. The sooner you treat an oil spill, the less it penetrates the concrete.
• Washing soda is available in the laundry aisle of most grocery stores (Arm & Hammer Super Washing Soda is the most common brand). Do not confuse it with baking soda — they are different compounds.
• Hot water significantly improves the effectiveness of this solution. Use the hottest tap water available.
• For extremely old, deep-set oil stains, you may need to repeat the process 2 to 3 times. Each application will pull more oil from the concrete pores.
• Do not use this solution on sealed or painted concrete floors — the alkalinity of washing soda can strip sealants and damage paint.