What About The Slab?

You want to select the right system. You want it installed correctly. You want it to last. You need to address the slab. If this is new construction your water/cement ratio should be .42 to .5 with a light steel trowel finish, and wet cured for a minimum of 7 days (blanket or plastic sheet – AVOID curing compounds.) Vapor retarder should be specified according to ASTM E1745-11. Curing compounds can create moisture and adhesion issues as well as increase the prep cost. Lightweight aggregates should be carefully selected since many are highly absorbent and can hold high levels of moisture past the cure and contribute to Alkali-Silica reaction that can cause spalling and potential structural damage. Many gypsum based and some lightweight concretes are also not compatible with some flooring systems.

Moisture Testing

In order to protect the owner/purchaser, moisture testing should be done by an ICRI certified 3rd party as the GC or installer may have a vested interest in the outcome. Moisture testing really should be done according to ASTM F2170 (In Situ RH testing), though some manufacturers require Tramex or CaCl (ASTM F2659 and F1869). A combination of In Situ and Calcium Chloride testing is often used. The In Situ RH testing will give you a better perspective of what’s in the slab and may be a problem once you install a system. It is also less affected by ambient conditions.

Surface Prep

In order for any system to do what it is supposed to, the floor needs to be properly prepared. It must be free of dirt, laitance, oil and other contaminants. The slab must also be sound. If there are damaged areas they should be repaired properly. The surface also needs to be properly profiled so that the system can achieve the necessary bond. This should be done using mechanical methods. Acid etching should not be used. See SSPC-SP13/NACE 6, ICRI 03732, and ASTM D4259-88.

Application Profile Prep Method
Sealers 3 Mils Grinding
Thin Mil 4-10 Mils Grinding
Thick Mil 10-40 Mils Shot Blast, Scarifying
Slurry/Broadcast 40 Mils-1/8" Shot Blast, Scarifying
Mortar 3/16" – 3/8" Shot Blast, Scarifying, Milling

Thin Mil Systems

  • Lowest cost option.
  • Fastest installation.
  • Shortest useful life.
  • Clear systems can be applied over penetrating concrete stains.
  • Lower chemical, abrasion, impact and traffic resistance.
  • Do not hide substrate imperfections
  • Decorative flake, colored stains under clear coats, solid colors and metallic pigments can be used to create unique looks
  • Often used to provide a clean, uniform surface in light commercial and retail applications. Sometimes used in residential, multi-family, and utility areas of hospitality and health care

Slurry or Broadcast Systems

  • 1/16 to 1/8 inch thickness.
  • Holds up to most wheeled traffic.
  • Greater durability than thin mil systems.
  • Long lasting slip resistance.
  • Decorative aggregates (quartz) and vinyl flake can be used.
  • Can help mask some surface imperfections.
  • More expensive than thin mil systems.
  • Longer installation time than thin mil systems.
  • Slurry systems are often used in health care facilities, food service, education, veterinary, and medium industrial facilities.
  • Can be installed with integral seamless sanitary coving.

Mortar Systems

  • 3/16 to 3/8 inch thickness.
  • Highest chemical, thermal shock, impact, and heavy duty traffic resistance.
  • Can be used to repair surface imperfections.
  • Decorative aggregates can be used.
  • Most labor intensive to install.
  • Mortar systems are often used in heavy manufacturing, high traffic, high chemical exposure, and food production areas as well as to resurface floors.
  • Can be installed with integral seamless sanitary coving

Epoxy Terrazzo

  • Typically installed at ¼ inch thickness, but can be placed thicker for sloping
  • Very low comparative life cycle cost.
  • Unlimited design options with matrix and aggregate color choices.
  • Granite can be used instead of marble for higher chemical resistance.
  • Novolac epoxy can also be used for higher chemical resistance.
  • Can be installed with integral seamless sanitary coving.