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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.

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: ____________
Good: ____________

Top Coat

Best: ____________
Better: ____________
Good: ____________

HP_Page-Concrete



Caution! Things to consider

  • For anti-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 (604) 596-6261.