Moisture Mitigation

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Moisture Mitigation Powered By Docstoc
					Subfloor Evaluation Prior
      to Installation
  Understanding the science of concrete
   slabs prior to installation of moisture
     sensitive floor covering materials
ASTM F-710 and ACI 302.2R-06
                          ASTM F-710

Ø   Preparation of Concrete Slabs to Receive Resilient
    l   Determination of suitability of a concrete subfloor for resilient
    l   Suggested construction methods for concrete slabs
    l   Suggested preparation methods of concrete floors for resilient
        flooring installation
              Related ASTM Procedures
Ø   C 109/C 109M Test Method for Compressive Strength of Hydraulic Cement Mortars
Ø   C 309 Specification for Liquid Membrane-Forming Compounds for Curing Concrete
Ø   C 472 Test Method for Compressive Strength of Gypsum Cement
Ø   D 4259 Practice for Abrading Concrete
Ø   E 1155 Test Method for Determining FF/FL (Floor Flatness and Floor Levelness)
Ø   E 1486 Test Method for Determining Floor Tolerances Using Waviness, Wheel Path,
    and Levelness Criteria
Ø   E 1745 Specification for Plastic Water Vapor Retarders Used In Contact With Soil or
    Granular Fill Under Concrete Slabs
Ø   F 141 Terminology Relating to Resilient Floor Coverings
Ø   F 1869 Test Method for Measuring Moisture Vapor Emission Rate of Concrete
    Subfloor Using Anhydrous Calcium Chloride
Ø   F 2170 Test Method for Determining Relative Humidity in Concrete Floor Slabs
    Using In Situ Probes
    General Guidelines of ASTM F-710

Ø   Dry, clean, smooth and structurally sound…
Ø   Surface cracks and control joints should be filled…and
    provide a minimum of 3000 psi compressive strength in
    28 days
Ø   Expansion joints shall not be filled…
Ø   Surface must be cleaned…
Ø   No asphaltic adhesive residues…
Ø   Shall be smooth and flat…within 3/16” in 10ft.
        Testing a Slab per ASTM F-710

Ø   Removal of sealers, curing agents, bond breakers
    otherwise known as the “water drop test”
Ø   Moisture Testing
    l   Moisture Vapor Emissions Rate (MVER)
    l   In Situ RH (Relative Humidity)
Ø   pH Testing
Moisture Testing per ASTM
      Preparation of New & Existing
          Concrete Subfloors
Ø   New concrete must      Ø   Existing concrete
    be cured and dried         must be free from any
    and in compliance          adhesive residues,
    with resilient floor       clean, dry and in
    covering                   compliance with
    manufacturer               resilient floor covering
    requirements               manufacturer
    Basic Concrete Slab Construction
Ø   Site evaluation
    l   Compressed soil
    l   Large aggregate (capillary
    l   Smaller aggregate
Ø   Moisture barrier
    l   0.010” thick reinforced film
Ø   Exterior Drainage and
    Landscaping concerns
                      ACI 302.2R-06
Ø   Guide for Concrete Slabs that Receive Moisture-
    Sensitive Flooring Materials
    lConcrete Moisture Basics

    lConcrete Moisture Testing

    lConcrete pH Testing

    lFloor Covering Adhesive Manufacturers Recommendations

    lDrying of Concrete

    lVapor Retarder/Barrier

    lFloor Covering Materials

    lDesign and Construction

“The objective of this document is to reduce the potential
 for moisture-related problems in both slabs-on-ground and
 suspended slabs. It provides basic information on the
 concrete drying process, moisture behavior in concrete,
 testing for pH and moisture, and vapor retarders/barriers.
 Based on this information, recommendations for the
 design and construction of concrete slabs that will receive
 moisture-sensitive or pH sensitive flooring materials or
 coatings are presented.”
Flooring Moisture Issues
             Concrete Moisture Basics

Ø   Understanding how water moves through hardened
    concrete is important in determining:
    l   Consequences of the moisture movement;
    l   Effectiveness of moisture testing methods; and
    l   Validity of flooring manufacturers’ warranty recommendations
                         Moisture Sources

Ø   Water of Hydration
    l   Water required to complete chemical reaction
         • Typically considered ~25% of cement by weight

Ø   Water of Convenience
    l   Water used for ease of workability and placement
         • Usually another 25% to 40% of cement by weight

Ø   Moisture Vapor Transmission (MVT)
    l   Water of convenience evaporating
         • 4” slab poured at .50 W/C evaporates >½ gallon per sq ft.
    l   Water coming up through the concrete from under slab
              Concrete Curing/Drying
Ø   After curing and before drying
    begins, the moisture distribution in
    a hardened concrete slab is
    reasonably uniform throughout the
    member thickness (Hanson 1968).
    As concrete dries, the amount and
    distribution of moisture changes
    (Hedenblad 1997).
      Curing/Drying of Lightweight &
            Normal Concrete
Ø   Drying profiles differ for normal weight
    and lightweight concrete;
Ø   Lightweight concrete takes longer to
    dry than normal weight concrete; and
Ø   Normal weight concrete takes less
    than 90 days and lightweight concrete
    takes more than 180 days to reach
    85% RH at the center of a 6 in. (150
    mm) diameter specimen.
        Effects of Moisture Movement
Ø   Warping or Curling
    l   Slab curls due to moisture
    l   Contractor grinds to bring into
        specification for flatness
    l   Floor covering or moisture
        barrier applied
    l   Concrete Equilibrates
    l   Slab Relaxes and areas
        ground and now lower
        Effects of Moisture Movement
Ø   Joint Bulging
    l   Slab poured
    l   Control Joints cut and due to
        normal slab shrinkage become “V”
    l   Patching compounds installed
    l   Floor covering installed
    l   Slab equilabrates and relaxes
    l   Patching compound compressed
        out of joint.
      Effects of Secondary Moisture
Ø   Concrete slabs, properly
    prepared and under
    functional HVAC control
    typically take 50-90 days
    to reach moisture levels
    suitable for “normal” floor
    covering installation
     l Rewetting resets the

        dry time clock my
        several weeks
           Concrete Moisture Testing

Ø   Standard test method, if applicable;
Ø   Acceptable test methods;
Ø   Frequency and location of testing;
Ø   Environment (before and during the test);
Ø   Surface preparation, if applicable;
Ø   Responsible testing party;
Ø   Acceptance criteria; and
Ø   Interpretation of results.
     ASTM Supporting Test Procedures
Ø   ASTM E 1907, “Standard Guide to Methods of Evaluating Moisture Conditions of Concrete Floors
    to Receive Resilient Floor Coverings,”
Ø   ASTM D 4263, “Standard Test Method for Indicating Moisture in Concrete by the Plastic Sheet
Ø   ASTM F 1869, “Standard Test Method for Measuring Moisture Vapor Emission Rate of Concrete
    Subfloor Using Anhydrous Calcium Chloride,”
Ø   ASTM F 2170, “Standard Test Method for Determining Relative Humidity in Concrete floor Slabs
    Using in situ Probes,” and
Ø   ASTM F 2420, “Standard Test Method for Determining Relative Humidity on the Surface of
    Concrete Floor Slabs Using Relative Humidity Probe Measurements and Insulated Hood.”
Concrete Moisture Testing
              Concrete pH Testing
Ø   Factors effecting pH
    l   Wetting Time
    l   Test Kit Components
    l   Carbonation
    l   Surface Preparation
    l   Water in the flooring
         Adhesive Recommendations

Ø   Vapor retarder/barrier
Ø   Concrete properties or materials
Ø   Curing
Ø   Surface finish
Ø   Floor flatness
Ø   Moisture limit
Ø   pH limit
Ø   Surface preparation
Ø   Repair
Typical Moisture Vapor Limits
Concrete Surface Criteria
              Drying of Concrete
Ø   Water to Cement
    ration (w/c) is the
    main driver for
    concrete drying
             Drying of Concrete
Ø   Thickness of concrete
    slab also impacts
    drying time
            Vapor Retarder/Barrier
Ø   Polyethylene based
    plastic sheet
Ø   Maximum perm rating of
    0.3 perms (1 grain per
    ft2/h per in. of mercury
Ø   Placed in direct contact
    with slab or with a
    “granular blotter layer”
    between the sheet and
                   Floor Covering Materials

Ø   Maintain open communication between architect and
    engineer to ensure Division 9 specifications are in line
    with Division 3 requirements for concrete.
    l   Section 09402 Epoxy Terrazzo;
    l   Section 09620 Specialty Flooring;
    l   Section 09621 Fluid-Applied Athletic Flooring;
    l   Section 09622 Resilient Athletic Flooring;
    l   Section 09640 Wood Flooring;
    l   Section 09651 Resilient Tile Flooring;
    l   Section 09652 Sheet Vinyl Floor Coverings;
    l   Section 09654 Linoleum Floor Coverings;
    l   Section 09671 Resinous Flooring;
    l   Section 09677 Static-Control Resilient Floor Covering;
    l   Section 09680 Carpet;
    l   Section 09681 Carpet Tile;
    l   Section 09960 High-Performance Coatings; and
    l   Section 09963 Elastomeric Coatings.
         Floor Covering Materials
Ø   Effect of Moisture on
    Floor Covering
    Adhesive bond
              Design and Construction

Ø   Specifications will usually include clauses related to:
    l   Testing;
    l   Moisture mitigation systems;
    l   Vapor retarder/barrier;
    l   Concrete materials and properties;
    l   Curing;
    l   Protection;
    l   Surface preparation;
    l   Repair materials; and
    l   Floor covering adhesives.
ASTM F-710-06 and ACI 302.2R-06

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