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Rejuvenating concrete shop floor

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  • Rejuvenating concrete shop floor

    As some of you know, I'm renovating a 1905 blacksmith shop to house my shop. The building has been used for multiple businesses since construction. Prior to my purchase of the structure, it was used by the local co-op as an oil drum storage facilty. As with any warehousing operation, there is bound to be some accidental breakage or spilling of material. Over a 30 year period, plenty of oil and grease was spilled either through leaking drums or careless workers. As a result, I have a concrete floor with heavy oil stains and dried oil residue.

    I'm looking for a good clean way to remove the dried oil residue from the floor. We plan to paint it with an epoxy paint once cleaned up. Has anyone else had a similar issue and how did you solve it?

    Last edited by scmw; 08-18-2010, 10:07 AM.

    There's only one way to find out, might as well get started now!

  • #2
    Open all the doors and put large fans in the doors to move the air through the shop. Buy 5 gals of mineral spirits, real mineral spirits not the crap some stores sell. Buy 4 or 5 bags of floor dry, spread the mineral spirits over a 6'x6' area and with a very stiff broom sweep the floor to loosen and help soak the mineral spirits in and add more mineral spirits as needed. Then cover the area with a layer of floor dry so no wet spots show through and leave it over night.

    You can do several areas at the same time but don't over do it. It takes several hours maybe 6 or 8 to soak it up. Sometimes you can reuse the floor dry several times depending on how oily the floor is.

    I have even used gasoline on very oily greasy areas. I also use a floor scraper to get built up grease and dirt off first.

    It's important to turn off any pilot lights or open flames in the shop and have good ventilation.

    The first business I owned had been a blacksmith shop, a tractor shop and a Model T Ford dealership in it's history since around 1900 and the floor had areas with 1" of dirt, grease and oil on it. The floor was like a gently rolling farm. Not all of it, just some areas had deep deposits.
    Last edited by Carld; 08-18-2010, 10:18 AM.
    It's only ink and paper


    • #3
      Cleaning oily concrete floor.

      Similar to Carl's way but a little different. I would open things up and spray the floor with Diesel and let it set. Depending on how much or how thick the build up it may need to be scraped and re done. After the concrete is clean but oily I would wet it and sprinkle Tide soap on it and let that soak for a while. Tide is the best readily avaliable soap. The old caustic soap used in steam cleaners is better but hard to come by. Rinse, squeege, and mop until clean.

      With that said one off the wall technique would be to rent a floor sander and/or a commercial wax poilisher and clean the floor with that.

      I have seen a company cleaning the parking lot at Wal Mart with a portable steam cleaner. There might be such a service in your area. A steam cleaner with caustic soap is the best for cleaning oily surfaces.
      Byron Boucher
      Burnet, TX


      • #4
        The last thing I would want to do is soak my floor in MORE nasty chemicals.

        I would either steam clean, or better, sandblast the whole thing first.

        I was just working on a jobsite last year where they sandblasted about 200,000 sq feet of concrete- gives it a nice tooth, cleans up most everything, and your epoxy will stick better.

        They even sandblasted after we drove a forklift on the floor, to get rid of tire marks. And back charged me for it...

        After that I wrapped all my forklift and manlift tires in silver duct tape. Cheaper than paying general contractors to sandblast.

        Anyway- you can buy a cheap sandblaster at harbor freight, rent a big compressor for a couple of days, and blast it to a nice clean matte finish.


        • #5
          I had a bad experience with painting my shop floor with epoxy paint. I originally painted my shop with 2-part epoxy, had to wear a gas mask. It looked terrific but after about 5 years it had chipped in several places plus I had built a large addition onto my shop so I wanted to repaint it in preparation for painting the new shop floor. I cleared my shop, cleaned the floor meticulously, sanded it until it was rough, completely removed all dust, and followed the manufacturer's directions when applying the paint. When the paint dried, I eagerly went down and looked at it. Uh-oh. Blisters. Lots and lots of blisters. Horrified, having spent a week to refinish my floor, I gave up on epoxy paint forever.

          If I had to do it again I would use good quality floor enamel. You can paint over it easily.



          • #6
            You might consider Trisodium Phosphate in warm water. It is sold as a paint surface prep under the tradename of "liquid sandpaper." You can usually buy it at paint stores or HD or Lowes, as a pure chemical. Dissolve it in water, about one cup per gallon, and scrub the floor with a stiff broom. It is very alkaline and will, given time, take the skin off your hands. Wear rubber gloves and take reasonable precautions; it is not THAT hazardous and it does a very good job of removing grease and oil.
            Duffy, Gatineau, Quebec


            • #7
              I hate to say it, but you might be reaching for the stars. You have a floor with decades of abuse and oil (and whatever else) that has penetrated deeply into the concrete. If it isn't 110% perfectly clean, the paint will peel or blister. Regardless, it will chip any time you drag something heavy across it or drop something. I have used enamel floor paint with success but in a low traffic area but I've decided against paint in my shop so I don't have to baby the floor.


              • #8
                Oil doesn't usually penetrate too deeply into concrete, unless it's so poor it should be removed and re-cast anyway. You could rent a floor grinder/planer and take the surface off then apply a self-levelling compound or screed topping then paint it.
                Peter - novice home machinist, modern motorcycle enthusiast.

                Denford Viceroy 280 Synchro (11 x 24)
                Herbert 0V adapted to R8 by 'Sir John'.
                Monarch 10EE 1942


                • #9
                  Load the TSP into the pressure washer and blast away!


                  • #10
                    Use any or all of the above suggestions then wash with a detergent to get rid of any remaining oil film, followed by a muriatic acid rinse to etch the concrete.


                    • #11
                      Sawdust works perfect. The finer the better. Grinding dust from wood is perfect. Spread it on the floor and wait a week. You'll be astonished how clean your floor is afterwards. And even better, you get the dust for free!

                      To por diesel onto the floor is the nominee for "Most stupid tip of the year".



                      • #12
                        To clean the floor I would recommend one of the very strong commercial detergents available instead of mineral spirits, gasoline or diesel. Not that these methods won't work but having experience as a firefighter for many years I believe it presents too much of a hazard, not only by fire but through inhalation. The home national chain improvement stores in my area carry detergents that are extremely strong and should do the job if use right out of the jug.
                        Regarding the epoxy coatings, I have mixed feelings. Epoxy coatings were applied to the floors in my Fire House twice, once when the floors were new and once later after the epoxy began coming up in large pieces. The areas most affected were the areas where the apparatus parked and it appeared that the hot tires added to the problem because it was especially bad where the tires stopped after calls. Sand blasting, as mentioned by a Ries, may prevent this, I can't say.


                        • #13
                          If you want a 2K coating, you simply can't do it without shot blasting the floor first. That's why professional coatings are expensive.

                          I recently laid a wooden floor in my shop. 22 mm thick, it will outlast me. Easy to repair, wood is oiled, so if I spill oil it will only get better. :-)

                          Looks like this, only wood is pine.



                          • #14
                            I suggest you use the solvent/floor dry first to get what you can from the pores in the floor. Follow with a cautic scrub wrinsing thoroughly.

                            Once the floor is clean, do a phosphoric acid etch using a pump sprayer. This may expose aggregate.

                            Any cracks should be immobilized. Bridge the cracks by trenching to half the slab thickness on 1 ft centers and grout in 1 ft length of re-bar, filling the cracks as you go.

                            At this point you may wish to survey the floor for soil subsidence. Drag a short length of heavy chain across the floor. If there is no support the floor will sound hollow there. Here you will have to make the decision to pump the slab to ensure full floor support. Look in the yellow pages.

                            Penultimately, apply a cementatious top dressing. There are some on the market that are very adherant and cure hard but you'll have to research them.

                            Once the floor is clean flat and dry you can move on to the the floor coating of your choice. If all previou has been successful your finished floor will look glass flat and .

                            As wth any paint job the prep is 90% of its success - even with concrete floors. The above is expensive and a lot of hard work but the finished product will be superb. You could eat off it, ball room dance, perform surgery, dissect the space shuttle, intall a praticle accellerator, build a clean room, anything where a very smooth easy to clean floor is required.
                            Last edited by Forrest Addy; 08-18-2010, 04:08 PM.


                            • #15
                              Long time Lurker, First Time Poster. The best way I've found to clean oil and grease from concrete is to use "Oil Dry" or "Kitty Litter," then make a scrubber from a broom handle and a 9" or so length of 2x4. Drill a hole at about a 45 degree angle in the 4" face of the 2x4 big enough for the broom handle and secure it with a wood screw. Spread the "Kitty Litter" on a section of the floor and use the 2x4 to scrub the grit into the oil or grease. I've found the best technique is to rock the 2x4 back slightly to apply a little more pressure. The "Kitty Litter" is very abrasive and will quickly grind off the old oil and grease, and it's natural liquid absorbency will soak up any liquid left. I've used this method for years in several garages.
                              Roger Monger, MBA
                              AFV Lab Manager
                              JMU, Harrisonburg, VA