Every manufacturer of floor covering has specific statements regarding the moisture content of the substrate to receive their flooring and the proper method of moisture testing. CONCRETE & MOISTURE
Excess moisture in concrete slabs causes a variety of flooring failures, disrupting building operations and necessitating expensive repairs. Consequences can be particularly serious in schools, hospitals and commercial installations where the loss of use of certain facilities, and hazardous conditions can jeopardize people’s safety, not to mention loss of business. CONCRETE & MOISTURE
Refuse to install Wait for the concrete to dry Fix the problem Accept a sign off from the general contractor!? When Moisture Testing Fails
Subfloor Preparation ASTM F 710 ASTM F 710 – Standard Practice for Preparing Concrete Floors to Receive Resilient flooring
ASTM F 710 Available from the American Society for Testing and Materials, 100 Barr Harbor Drive, West Conshohocken PA 19428;  832-9500; www.astm.org www.astm.org Preparation of concrete slabs to receive resilient flooring
ASTM F 710 (cont.) Dry, clean, smooth, and structurally sound. Free of dust, solvent, paint, wax, oil, grease, residual adhesive, adhesive removers; curing, sealing hardening, or parting compounds; alkaline salts, excessive carbonation or laitance, mold, mildew, and other foreign materials that might prevent adhesive bond Calcium chloride moisture tests [ASTM F 1869]; results should be 3 pounds or less or resilient flooring manufacturer’s recommendations
ASTM F 710 (cont.) Relative Humidity [ASTM F2170] 75% or less Alkalinity testing; maximum pH of 10 Don’t use adhesive removers. Flatness requirements: ±1/8” in 10 feet Drying time for slab: minimum of 60 to 90 days Moisture retarders recommended under all on-grade and below-grade concrete floors.
Other Contaminants Dry Wall Mud Paint Overspray Oil & Grease Asphalt or Tar
Other Contaminants (cont.) Flooring Adhesives On a concrete substrate only. Not water soluble. Scrape to a thin well bonded residue. Asbestos Adhesive - Wet-Scrape Only! Follow the guidelines of the Resilient Floor Covering Institute and comply with state and local laws. Resilient Floor Covering Institute 401 East Jefferson Street, Suite 102 Rockville, Maryland 20850 Telephone: 301-340-8580 www.rfci.com
Mechanical Cleaning of Concrete Shot Blasting Scarifying Scabbling Bush-Hammering Grinding Sand or Water Blasting
The use of sanding equipment is not sufficient to remove curing and sealing compounds from the surface of concrete!
Do not use chemicals such as adhesive removers or acid to prepare the concrete!
Adhesive Removers The only part of our industry that recommends adhesive removers are the adhesive remover manufacturers! The use of solvents and “removers” on concrete will result in failure! Mechanically clean the concrete!!!
Acid Etching Cannot be 100% certain that acid is neutralized. Introducing a tremendous amount of water to the concrete. Mechanically clean the concrete!!!
Other Concrete Substrates Lightweight Concrete must be structural lightweight! Min. 3,000 psi in compressive Min. 100 lb.cu.ft. in density
Summary-failure to properly prepare a concrete substrate Mechanical preparation not used on standard concrete Concrete inherently weak – should have a tensile strength of at least 200 psi Assumed no curing compound was used or that it had dissipated Sealer remaining on concrete substrate
Used adhesive removers or acid etching Adhesive residue too thick Went over expansion joint Went over moving crack Went over isolation joint Summary - failure to properly prepare a concrete substrate
Substrates Non-Porous Substrates Ceramic Tile – make sure tile is solidly bonded.
Metal Make sure foils are solidly adhered with epoxy! Substrates Non-Porous Substrates
Epoxy Coatings If these can be removed, do so. Don’t assume they are solidly bonded. Substrates Non-Porous Substrates
Terrazzo Make certain that sealers, waxes and dressings are completely removed. Substrates Non-Porous Substrates
Summary - failure to properly prepare a non-porous substrate Loose ceramic tile not removed. Metal foil not solidly bonded. Epoxy system flaky or disbonding. Wax or dressing not stripped from terrazzo.
Plywood/OSB Solid Strip or Plank Make sure all are structurally sound and solid and installed according to code.
Suitable for uses not permanently exposed to the weather. Panels classified as Exposure 1 are intended to resist the effects of moisture on structural performance due to construction delays, or other conditions of similar severity. Type 1 Plywood
Prepared to bare wood Surface may require primer and the use of a lath mesh. Additive may be required to further accommodate movement. Joints must be filled full width and depth. All wood must be:
Summary- failure to properly prepare a wood subfloor Wood not structurally sound Inadequate fastening of wooden subfloor Didn’t use lath or additive as required
Categories of Materials Used Gypsum-based Portland cement-based Self-leveling Trowel grade
Use a Portland cement- based material Can be used on all grade levels Can handle periodic moisture Have similar compressive strengths to that of the structural concrete – 3000 to 4000 psi
When to use a Trowel grade or Self-leveling Material Do not base it on square footage. Do not base it on substrate. Do not base it on the thought that trowel grade materials dry faster than self-leveling materials.
When to use a Trowel grade or Self-leveling Material Look at the thickness needed to achieve the required flatness or level of the concrete. 1/8” or less use a patching material 1/8” or greater float the substrate with a self-leveling material. Look at the whether a slope is required.
Selecting a Self-leveling Material Versatility Installs over any common substrate – concrete, non-porous, wood, metal & adhesive residues. Installs to any thickness. Install flooring in 16 hours – even at any thickness. Some Self-leveling materials can have flooring installed in 2 hours.
Selecting a Self-leveling Material Not all Self-leveling materials are the same. Compare Apples to Apples. Some materials may be limited to certain substrates. Some materials may be limited in thickness. Some materials may take longer to dry – 2 to 3 days.
Selecting a Self-leveling Material Select a material that fits the job. Select a material that has a track record. Select a material that is Portland Cement-based. Select a material that is recommended by the flooring manufacturers.
Selecting a Patching Material Decide whether a skim coating or ramping and sloping material is needed
Selecting a Patching Material Ramping/Sloping Material Fluid consistency that is easily screeded but can maintain slope. Installs up to 3” Install flooring quickly – even at 3” in thickness.
Selecting a Patching Material Skim coating material Unsanded Installs over any common substrate – concrete, non-porous, wood, metal & adhesive residues. Dries quickly Has excellent coverage.
Selecting a Patching Material Not all Patching materials are the same. Once again, compare Apples to Apples. Some materials may be limited to certain substrates. Some materials may require an additive. Some materials may be limited in thickness. Some materials may take longer to dry – 1 to 3 days. Coverage per pound may vary from on product to another.
Selecting a Patching Material Select a material that fits the job. Select a material that has a track record. Select a material that is Portland Cement-based. Select a material that is recommended by the flooring manufacturers.
Improper product selection Substrate not appropriate for the Self- leveling or patching material. Gypsum product used on or below grade. Used self-leveling material instead of trowel-grade material or the reverse. Applied too thick.
Improper Mixing of the Self- leveling or patching material “Over-watering” – the number one cause of failures when it comes to patching materials! Didn’t use additive as required.
Installation of the Self- leveling or patching material Improper Installation of the Self- leveling or patching material Inadequate drying time allotted. Primer applied too thick. Wrong primer for type of substrate.
Surface defects not detected prior to installation of flooring