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
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Preparation of Concrete Slabs to Receive Resilient
Flooring
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Determination of suitability of a concrete subfloor for resilient
flooring
Suggested construction methods for concrete slabs
Suggested preparation methods of concrete floors for resilient
flooring installation
Related ASTM Procedures
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C 109/C 109M Test Method for Compressive Strength of Hydraulic Cement Mortars
C 309 Specification for Liquid Membrane-Forming Compounds for Curing Concrete
C 472 Test Method for Compressive Strength of Gypsum Cement
D 4259 Practice for Abrading Concrete
E 1155 Test Method for Determining FF/FL (Floor Flatness and Floor Levelness)
E 1486 Test Method for Determining Floor Tolerances Using Waviness, Wheel Path,
and Levelness Criteria
E 1745 Specification for Plastic Water Vapor Retarders Used In Contact With Soil or
Granular Fill Under Concrete Slabs
F 141 Terminology Relating to Resilient Floor Coverings
F 1869 Test Method for Measuring Moisture Vapor Emission Rate of Concrete
Subfloor Using Anhydrous Calcium Chloride
F 2170 Test Method for Determining Relative Humidity in Concrete Floor Slabs
Using In Situ Probes
General Guidelines of ASTM F-710
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Dry, clean, smooth and structurally sound…
Surface cracks and control joints should be filled…and
provide a minimum of 3000 psi compressive strength in
28 days
Expansion joints shall not be filled…
Surface must be cleaned…
No asphaltic adhesive residues…
Shall be smooth and flat…within 3/16” in 10ft.
Testing a Slab per ASTM F-710
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Removal of sealers, curing agents, bond breakers
otherwise known as the “water drop test”
Moisture Testing
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Moisture Vapor Emissions Rate (MVER)
In Situ RH (Relative Humidity)
pH Testing
Moisture Testing per ASTM
Preparation of New & Existing
Concrete Subfloors
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New concrete must
be cured and dried
and in compliance
with resilient floor
covering
manufacturer
requirements
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Existing concrete
must be free from any
adhesive residues,
clean, dry and in
compliance with
resilient floor covering
manufacturer
requirements
Basic Concrete Slab Construction
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Site evaluation
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Moisture barrier
specifications
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Compressed soil
Large aggregate (capillary
break)
Smaller aggregate
0.010” thick reinforced film
Exterior Drainage and
Landscaping concerns
ACI 302.2R-06
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Guide for Concrete Slabs that Receive MoistureSensitive Flooring Materials
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Introduction
Concrete Moisture Basics
Concrete Moisture Testing
Concrete pH Testing
Floor Covering Adhesive Manufacturers Recommendations
Drying of Concrete
Vapor Retarder/Barrier
Floor Covering Materials
Design and Construction
Introduction
“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
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Understanding how water moves through hardened
concrete is important in determining:
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Consequences of the moisture movement;
Effectiveness of moisture testing methods; and
Validity of flooring manufacturers’ warranty recommendations
Moisture Sources
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Water of Hydration
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Water required to complete chemical reaction
• Typically considered ~25% of cement by weight
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Water of Convenience
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Water used for ease of workability and placement
• Usually another 25% to 40% of cement by weight
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Moisture Vapor Transmission (MVT)
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Water of convenience evaporating
• 4” slab poured at .50 W/C evaporates >½ gallon per sq ft.
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Water coming up through the concrete from under slab
Concrete Curing/Drying
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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
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Drying profiles differ for normal weight
and lightweight concrete;
Lightweight concrete takes longer to
dry than normal weight concrete; and
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
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Warping or Curling
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Slab curls due to moisture loss
Contractor grinds to bring into
specification for flatness
Floor covering or moisture
barrier applied
Concrete Equilibrates
Slab Relaxes and areas
ground and now lower
Effects of Moisture Movement
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Joint Bulging
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Slab poured
Control Joints cut and due to
normal slab shrinkage become “V”
shaped
Patching compounds installed
Floor covering installed
Slab equilabrates and relaxes
Patching compound compressed
out of joint.
Effects of Secondary Moisture
Exposure
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Concrete slabs, properly
prepared and under
functional HVAC control
typically take 50-90 days
to reach moisture levels
suitable for “normal” floor
covering installation
 Rewetting resets the
dry time clock my
several weeks
Concrete Moisture Testing
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Standard test method, if applicable;
 Acceptable test methods;
 Frequency and location of testing;
 Environment (before and during the test);
 Surface preparation, if applicable;
 Responsible testing party;
 Acceptance criteria; and
 Interpretation of results.
ASTM Supporting Test Procedures
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ASTM E 1907, “Standard Guide to Methods of Evaluating Moisture Conditions of Concrete Floors
to Receive Resilient Floor Coverings,”
ASTM D 4263, “Standard Test Method for Indicating Moisture in Concrete by the Plastic Sheet
Method,”
ASTM F 1869, “Standard Test Method for Measuring Moisture Vapor Emission Rate of Concrete
Subfloor Using Anhydrous Calcium Chloride,”
ASTM F 2170, “Standard Test Method for Determining Relative Humidity in Concrete floor Slabs
Using in situ Probes,” and
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
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Factors effecting pH
Testing:
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Wetting Time
Test Kit Components
Carbonation
Surface Preparation
Water in the flooring
adhesive
Adhesive Recommendations
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Vapor retarder/barrier
 Concrete properties or materials
 Curing
 Surface finish
 Floor flatness
 Moisture limit
 pH limit
 Surface preparation
 Repair
Typical Moisture Vapor Limits
Concrete Surface Criteria
Drying of Concrete
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Water to Cement
ration (w/c) is the
main driver for
concrete drying
Drying of Concrete
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Thickness of concrete
slab also impacts
drying time
Vapor Retarder/Barrier
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Polyethylene based
plastic sheet
Maximum perm rating of
0.3 perms (1 grain per
ft2/h per in. of mercury
pressure.)
Placed in direct contact
with slab or with a
“granular blotter layer”
between the sheet and
concrete.
Floor Covering Materials
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Maintain open communication between architect and
engineer to ensure Division 9 specifications are in line
with Division 3 requirements for concrete.
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Section 09402 Epoxy Terrazzo;
Section 09620 Specialty Flooring;
Section 09621 Fluid-Applied Athletic Flooring;
Section 09622 Resilient Athletic Flooring;
Section 09640 Wood Flooring;
Section 09651 Resilient Tile Flooring;
Section 09652 Sheet Vinyl Floor Coverings;
Section 09654 Linoleum Floor Coverings;
Section 09671 Resinous Flooring;
Section 09677 Static-Control Resilient Floor Covering;
Section 09680 Carpet;
Section 09681 Carpet Tile;
Section 09960 High-Performance Coatings; and
Section 09963 Elastomeric Coatings.
Floor Covering Materials
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Effect of Moisture on
Floor Covering
Adhesive bond
strength
Design and Construction
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Specifications will usually include clauses related to:
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Testing;
Moisture mitigation systems;
Vapor retarder/barrier;
Concrete materials and properties;
Curing;
Protection;
Surface preparation;
Repair materials; and
Floor covering adhesives.
ASTM F-710-06 and ACI 302.2R-06
THANK YOU