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Monday, January 18, 2010


Advice from the Pros:

Concrete Lessons in Prep: When the Cure Is the Problem

 painted_garage_floor  

Concrete can be a challenging surface to coat, but the continuous traffic of heavy (3,000- to 5,000-pound) vehicles, plus the friction from tire starts, stops and pivots on a garage floor calls for heavy-duty finishes. Add in the dirt, salt, leaks and spills, and we're talking industrial finishes. But as with most finishes, it often comes down to the universal truth that a finish is only as good as the surface beneath. Translation: Spray, brush or roll, applying a coating over oil, dust, mold, grease or anything other than a squeaky-clean substrate, means the paint (or epoxy, in this case) is merely coating residue, not the actual surface. Nothing illustrates this better than a job we visited a couple of years ago. An epoxy coating had just been applied to the floor of a customer's seven-bay garage. The industrial finish was dry, though still due for a seven day curing period before it would take on the pressure from 24 tires, under the weight of six high-performance vehicles. But as the contractor began to remove strips of low-tack tape from the masked edges, he was dismayed to see the epoxy finish lifting right up with it. His first thought was product failure. After all, the nearly new concrete floor had no oil spots or any other stains and he'd even pressure-washed the surface to remove all dust and debris. He assumed the poor adhesion was the fault of the Benjamin Moore P42 and contacted his local paint dealer.

After covering the usual suspects with the contractor (incomplete surface prep, improper handling of product, application errors, etc.), the store manager turned to Benjamin Moore's technical support team.  

To address a predicament of this scale we needed to visit the site and, at first review, things seemed to be in order:

  • The concrete had well more than its required cure time of 28 days. Check.
  • The contractor had tested for evidence of moisture issues. No problems there. Check.
  • Again, the floor had been pressure-washed...

And that's when the inquiries came to a screeching halt. For concrete to accept stain, paint or epoxy, it needs to be  porous and have the texture of medium grit sand paper. A power washer will blast away dust, dirt and loose finishes, but it cannot remove the invisible barrier of a curing compound--a sealer that masonry contractors apply to help lock in the water  of newly poured concrete to properly cure the substrate.. In the old days, they would lay wet burlap bags over fresh pours to retard drying so the concrete would cure properly. But the modern spray-on sealers are  more reliable and easier to deal with, unless, of course, you want to apply a finish to the concrete, in which case it acts as an invisible barrier.

So how do you know if concrete is ready to accept a new finish? Here are some basic steps:

  • Assess the current conditions. Even if there is no previous finish, you still need to remove all dirt, residue, oils, etc. So, unless the concrete is brand new, clean with an oil-and-grease emulsifier such as Benjamin Moore P83 (a concentrated degreaser). If the surface has a sealer or curing compound on it or the existing finish is failing it must be totally removed and profiled using a mechanical process, ie shot blasting.
  • Test for porosity: spatter the concrete with water droplets. If they soak in, the surface is absorbent. If the water beads up, any finish you apply will sit on top, too. To create the absorbency needed, abrade the surface, either mechanically or chemically. For a fast method, check with your retailer about leasing a machine equipped with grinding wheels. Or you can apply an acid etching product such as Benjamin Moore P85 Concrete Pretreatment and Etch.
  • Always check for migrating moisture before applying any finish. It can push a coating right off the surface. To test, cut a 2-ft. x 2- ft. piece of 1-mil poly and duct tape it to the floor, sealing all four edges. Leave it there for 24 to 48 hours. If you see condensation under the plastic, seek professional help, (found through the retailer locator at www.benjaminmoore.com).
  • If the surface has a previous coating, it also must be clean (see above) and sound. To check for stability of the finish, here's another tape test: Firmly press a piece of heavy-duty tape to the finish and pull it off quickly. If the tape lifts any paint, you need to strip the paint from the surface.
  • If the existing finish is firmly fixed, make sure the new coating is a compatible product. We'll cover how to select the right finish options in an upcoming posting.

The bottom line is--and always has been--a finish is only as good as the surface beneath. It's simple, but not easy, which is why 99 percent of paint failures are the result of poor prep.

So what happened at the garage? Unfortunately, the contractor had to remove the failed coating and create a profile using a mechanical process, i.e. shot blasting, and then re-install the P42 system. And now, when they're not scooting about, the vehicles and their tires perch atop a fine film of P42.

Comments

He is a good friend that speaks well of us behind our backs.

I have a stamped concrete driveway in which the paint is pealing. I think it is a latex paint but Im not sure. I would like to know what type of expoxy concrete paint you would recommend and the steps I should take to make sure it adheres properly. Thanks in advance
Tony

Hey folks. You ever been in someone’s garage and they have that really nice sealed floor? , well that’s what I’ve got in my garage and I absolutely love it!

If you are preparing to paint your car or simply considering the option the first thing you need to know about Auto paint colors is that not all colors work for all cars. If you think about cars that has been driving around town, you can probably think of some very different cars that made him think that what they were thinking about painting the car that color.

Anthony, Surfaces to be painted must be clean, dry and free of dirt, mildew, oil, or grease. Glossy surfaces must be dulled. Once these steps have been taken, we would recommend to prime the trim with Benjamin Moore Fresh Start® All Purpose 100% Acrylic Primer 023. Once primed you may topcoat with either our Impervex High Gloss 309, Aura Semi Gloss 528, or ideally any latex finish.

I will be repainting previously painted trim with a latex gloss product. The product that was previously used was oil based. It has been 10 years since it was last painted. Do I need to scuff up the woodwork and doors before applying the new product? Please advise.

Also, any product that you could suggest would be most helpful as well.

Thank you!

Sorry for the delay. Are you looking for concrete color help or wall color help? Let us know and we'd be happy to help.

I HAVE A NEW CONSTRUCTION CONDO 27TH FLOOR THAT I HAVE PURCHASED CONTEMPORARY FURNITURE. MY FLOORS ARE JERUSALEM STONE AND HAVE A YELLOW COLOR TO THEM WITH GREY & WHITE VEINS. I LOVE THE INDUSTRIAL LOOK AND ALSO LIKE TAUPEY COLORS

IM CONFUSED CAN SOMEONE HELP

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