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How to Clean Concrete Floors Before Painting

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Although predominately thought of as dull and gray, concrete floors are becoming trendier and more appealing to homeowners. Painting concrete floors gives them a personalized touch and enhances their beauty. Paint is capable of transforming boring, traditional concrete floors into colorful design features that complement any décor style. Like walls, concrete floors require cleaning before they are painted to remove grease, dirt and grime buildup, which obstruct paint’s bond to concrete. Thoroughly clean concrete floors before painting using a heavy-duty cleaning solution.

Sweep the entire concrete flooring with a broom. Clear all loose grit, grime and debris from the concrete.

Prepare to mop the concrete with a trisodium phosphate solution (TSP). Since TSP contains harsh cleaning agents that irritate skin, put on goggles and heavy-duty rubber gloves to wear throughout the cleaning project.

Mix 2 gallons of hot, clean water with 1/2 cup of trisodium phosphate in a mop bucket. Stir the solution until the TSP granules fully dissolve.

Prepare another mop bucket full of warm water.

Mop the TSP solution onto the entire concrete floor using a sponge mop. Scrub areas of the concrete containing stuck-on grime with a stiff nylon brush. As you’re mopping, rinse the mop regularly in the water to prevent contaminating the TSP solution.

Refill the bucket of water with clean water. Mop the entire concrete floor with the clean water to rinse the TSP solution.

Extract the grimy mop water from the concrete using a wet/dry vacuum. Let the concrete thoroughly air-dry before painting.


Detach very stubborn grime using a rotary floor scrubber. Operate the rotary floor scrubber according to manufacturer’s instructions.


Keep the TSP solution away from your skin and eyes as burns may result.

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