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For Your Home Concrete & Garage Floors

Paint a Concrete Floor

Project Scenario

Jim wants to paint the floor in his manufacturing work shop. There is impact from dropped tools, but no forklift or heavy equipment use.

Red Alert

A moisture test is MANDATORY. Perform a moisture test (ASTM3359)

  • Use 4 mil visqueen (2 feet x 2 feet)
  • Duct tape all four sides to floor.
  • Wait 24 hours and look for condensation under the plastic.
  • If wet, do not paint because of hydrostatic pressure.

Preparation

  • Complete a moisture test (above).
  • Remove dirt and grease by scrubbing with hot water and a strong degreaser or detergent. Rinse thoroughly. The wet surface, when clean, should be one continuous sheet of water with no beading in any areas.
paint-concrete-floor
  • Rough up smooth floor to achieve the look of 100 grit sandpaper using one of the following methods:
    • Acid etch if there is a drain (May require multiple applications)
    • Blast-trac (Do not overdue profile or extra coats may be required)
    • Grind and Go.
  • All dust must be removed by vacuum or mop. Let dry thoroughly.
  • Clean cracks out to remove loose concrete, obtain and apply a paintable concrete patch.
  • Fill cracks with an epoxy crack filler designed to be painted.
  • Check walls for moisture before coating. Determine and correct the source of moisture before painting.

Primer Coat
Best:  709401x Ropon Epoxy High Solids Primer
Good:  841001 INSL-X Garage Guard System

Top Coat
Best:  759301x Polycoat High Solids
Better:  709401x Ropon Epoxy High Solids
Good:  841001 INSL-X Garage Guard System

Caution! Things to consider

  • For anit-slip, non-skid coating, add sand to the film, by hand broadcast, during the first primer coat. Create test area to determine how much sand to add.
  • If floor is exposed to sunlight, be aware that epoxy coatings yellow over time. Polyurethane coatings are more resistant to UV exposure.
  • Do not let acid solutions dry. They will be very hard to remove.
  • Do a test patch to check for adhesion.
  • Before painting, extinguish any open flames such as pilot lights on furnaces and gas water heaters.
  • Fill expansion joins after the floor is coated. Top coatings will not flex over the joint filler. Cracking and flaking of the paint will occur.
  • Epoxies will chalk out in the presence of sunlight. A 2 part polyurethane topcoat will keep the floor color and gloss retention.
  • No floor coating is indestructible. In areas subject to abuse, floor mats are a good idea to protect the paint from being chipped when items are dropped.
  • Do not use alkyd paints if there are moisture problems. Alkyd paints will peel up when lime is present.

For more information about this or other painting tips & techniques, our paint & coatings products, or general DIY paint and coatings questions, please contact us online or by calling 1-800-452-2315.