A quality batch of concrete should consist of at least a 5-sack mix with minimal fly ash, no retarder, curing compounds or chloride accelerators.  Do not pour below 40°F. Do not use fly-ash below 80°F. Use no more than 15% fly-ash above 80°F.   The slab should be hard troweled by machine to a smooth finish.  It is NOT necessary to burnish the surface to a slick, mirror finish.  “Burning” the slab to an ultra smooth surface will close off the pours of the slab and cause the stain to sit on top of the concrete and not penetrate.  A bit smoother than a Garage Floor is optimum.  Make sure the Finishers don’t get “burrs”, rocks or trash caught under the blades which can cut swirl marks into the slab. 

      It is important that the concrete be thoroughly finished with hand tools where needed around the plumbing, risers, floor outlets, or any other element which is not accessible by the machine.  Special care should be taken to blend in the areas at the exterior edges of the slab.  If the finish is smooth in the center and rough finished at the edges, there will be a noticeable difference of color and tone between these areas.

      Silicone chalks should NOT be used if at all possible.  The RED and yellow chalks are PERMANENT DYES.  RED Chalk should NOT be used for framing.  White or Blue chalks are OK.  Do NOT use silicone sprays to “Hold” the lines.  The sprays repel the stain and leave harsh, permanent scars on the floor.

      It is important that wood, sheet goods, sections of framing and the like not lay on the slab for extended periods of time.  They can transfer resins and tannins into the slab.  This will alter the moisture content in the slab which leaves a pattern in the finished floor.  Cardboard should be placed between the slab and the stacked material to minimize any unwanted transfers.

      The floor should be protected from the following:   Plumbers Glue, Foam Insulation, Bond Release Agents, Flux, Oils, Grease, Polyurethane, Paint, Markers (framers often write dimensions of doorways in marker on the slab.  Ask them to make that note on the wood framing the doorway), Grease Sticks, Spray Paints, Crayons, Muratic Acid, and other chemicals both before and after staining.  Also ask that locations of Electrical and other outlets be marked on the studs and not on the floor.

      The framers should brace the walls to the outside and not to the slab.  Door plates should be cut away immediately.

      The floors should be clean and the rooms empty, with absolutely nothing on the floors prior to the arrival of the stain crew.  The best time to stain the floors is when you are Blacked-In with a Roof on.  The slab is at it’s cleanest at this point in time.  After the Stain and Sealer, we cover the floor with 2 layers of corrugated cardboard to protect it from the Drywall Mud.  After the mud work is done, remove the top layer of cardboard and the remaining layer will protect the floor from the  Paint process.

      At the “Pre-Trim” stage, a refresher coat of sealer will bring the floors back to life.

      It is extremely important that you do not tape the floor!  When covering the floor, overlap sheets of cardboard  (Roofing paper is a great covering item too).  Tape the first sheet to the wall then overlap the second sheet to the first and tape it to the paper.  DO NOT TAPE TO THE FLOOR.  Duct Tape, Masking Tape, Packaging Tape, Strap Tape, Blue Tape, Green Tape, Stucco Tape and Electrical Tape – there are NO exceptions.  The tape alters the natural curing process and transfers chemicals to and from the slab.  If tape is placed on the sealer, it will pull the sealer off of the floor.  This is called Plasticizer Migration and it WILL SHOW in the finished product. 

      When covering the floor, do not cover the floor with plastic at any time!  It prevents the slab from breathing which inhibits proper curing.  It can result in efflorescence.

      To learn more about Slab Preparation for Stained Concrete, Visit Stained By Design's website