Common Causes of FlooringFailures and How to Prevent

ThemHESNI 2015 Annual Conference

7 May 2015Emily O’Keefe

Simpson Gumpertz & Heger Inc. is a Registered Providerwith The American Institute of Architects ContinuingEducation Systems. Credit earned on completion of thisprogram will be reported to CES Records for AIAmembers. Certificates of Completion for non-AIAmembers are available on request.

This program is registered with the AIA/CES forcontinuing professional education. As such, it does notinclude content that may be deemed or construed tobe an approval or endorsement by the AIA of anymaterial of construction or any method or manner ofhandling, using, distributing, or dealing in any material orproduct. Questions related to specific materials,methods, and services will be addressed at theconclusion of this presentation.

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© Simpson Gumpertz & Heger Inc. 2015

Learning Objectives

1. Understand that moisture in concrete floors canlead to floor finish problems.

2. Identify good practices and preventativemeasures for limiting moisture levels in concretefloors.

3. Learn the current moisture test methods forconcrete, their limitations and how to interpretresults.

4. Learn how to evaluate and select measures tomitigate high moisture levels in concrete floors.

Presentation Outline

• Flooring Failures

• Typical Causes of Flooring Failures

• Why so many failures now?

• Minimizing the Risk

• Case Studies

5

Flooring Failures

Flooring Failures on Concrete

• Vinyl

– VCT

– Sheet

– Simulated Wood

• Hardwood

– Oak

– Ash

– Maple

– Bamboo

• Carpet

– Broadloom

– Carpet Tile

• Terrazzo

– Cementitious

– Epoxy

• Coatings

– Epoxy

– Urethane

– MMA

– Vinyl Ester

• Rubber Tile

• Silicates

• Stains

• Underlayments

Adhesive Failure

Vinyl Flooring Failures

Wood Flooring Failures

Carpet Failures

Resinous Terrazzo Failures

Coating Failures

Typical Causes ofFlooring Failures

Typical Causes of Flooring Failures

• Primary Causes

– Moisture

Sources of Moisture

• Underlying Soil

• Concrete

• Cleaning and Maintenance

• Ambient Conditions

Adhesive Staining + Sliding Tiles

Wet Concrete

Discolored Artificial Stone Tiles

Concrete Slab-on-GradeNo Vapor Retarder beneath Slab

Stains on Engineered Wood Flooring

Elevated Concrete Deck

Exposure to Exterior Moisture

Ruts in Sheet Vinyl with Soft, MigratingAdhesive

Elevated Concrete Deck

Epoxy Terrazzo Blisters and SurfaceDeposits

Concrete Slab-on-GradeVapor Retarder beneath Blotter Layer

Typical Causes of Flooring Failures

• Primary Causes

– Moisture

– Quality and Preparation of Concrete

Surface Preparation

• Surface preparation directly affects adhesion.

• Remove bond-breaking substances to improvechemical adhesion.

• Roughen surface and remove unsound materials toimprove mechanical adhesion.

Concrete Surface Profiles (CSP)

Concrete Surface Preparation Methods

Delaminated Ceramic Floor Tiles

Ineffective Surface PreparationContaminated Surface

Slippery White Deposits on WarehouseFloor

Surface Contamination of Silicate Hardener Residue

Blisters in Epoxy Floor Coating

Surface Contamination of Silicate Hardener Residue

Typical Causes of Flooring Failures

• Primary Causes

– Moisture

– Quality and Preparation of Concrete

• Secondary Causes

– Product Selection

– Cleaning and Maintenance

– Environmental Exposure (humidity, sun, etc.)

Product Selection Issues

System Selection Issues

System Selection Issues

Environmental Exposure

34

Environmental Exposure

35

Why So ManyFailures Now?

Why have we seen so many failuresnow?

• Change in materials (governmentregulations and environmentalconsiderations)

Asphalt Cutback Adhesives

SCAQMD Rule 1168 (2005)

Carpet Policy Dialogue

VOC Regulations by State or Region

Why have we seen so many failuresnow?

• Change in materials (governmentregulations and environmentalconsiderations)

• Blended cement (fly ash) concretes

Concrete with and without Fly Ash

Concrete microstructure withoutfly ash at 200X magnification.

Concrete microstructure with 20%fly ash at 200X magnification.

Why have we seen so many failuresnow?

• Change in materials (governmentregulations and environmentalconsiderations)

• Blended cement (fly ash) concretes

• Use of lightweight concrete

Normal Weight vs. Lightweight Concrete

• 110 to 115 pcf vs. 145 to 150 pcf

• Expanded slate and shale aggregate

Normal Weight vs. Lightweight Concrete

Figure from ACI 302.2R-06

Normal Weight vs. Lightweight Concrete

From Concrete International, January 2012

Why have we seen so many failuresnow?

• Change in materials (governmentregulations and environmentalconsiderations)

• Blended cement (fly ash) concretes

• Use of lightweight concrete

Why have we seen so many failuresnow?

• Change in materials (governmentregulations and environmentalconsiderations)

• Blended cement (fly ash) concretes

Why have we seen so many failuresnow?

• Change in materials (governmentregulations and environmentalconsiderations)

• Blended cement (fly ash) concretes

• Fast track construction

Minimizing theRisk

Minimizing the Potential for Floor Failures

• Concrete

• Testing

• Moisture Mitigation

52

Get It Dry and Keep It Dry

Minimizing the Potential for Floor Failures

• Concrete

• Testing

• Moisture Mitigation

53

Planning Ahead for Flooring Installation

54

Preconstruction

Start Construction

Concrete Placed

Building Enclosed

HVAC Operational Flooring Installed

Building Occupancy

REWETTING DRYING

In Progress Construction

Concrete Design

• Vapor retarder should comply with ASTME1643

• Prohibit the use of a sand blotter layer

56

Slab-on-Ground without a VaporRetarder

Slab-on-Ground without a VaporRetarder

Slab-on-Ground with a VaporRetarder

Location of the Vapor Retarder

From ACI 302.2R

Slab-on-Grade with Blotter Layer

Slab-on-Grade with Blotter Layer

Slab-on-Grade with Blotter Layer

Location of the Vapor Retarder

From ACI 302.2R

Installation of Sand Blotter Layer

Sand BlotterLayer

VaporBarrier

Preparation for Compaction of Blotter Layer

Concrete Design

• Limit water content (our typicalrecommendations):

– 0.40 maximum w/c ratio for NW concrete

– 0.45 maximum w/c ratio for LW concrete

– 300 lb/cyd maximum water content

– Use as large an aggregate size as possible

– Use a good aggregate gradation

• Limit fly ash and slag to 5-10%

67

Concrete Design

• Prohibit addition of water beyond approvedmix design in the field

• Water-reducing Admixtures

• Shrinkage-reducing Admixtures

– Consider for use with slabs-on-grade toreduce curling and cracking

68

Concrete Construction

• Floor Flatness (FF) and Floor Levelness (FL)

• Curing

69

Floor Flatness and LevelnessCoordination

70

Curing

• Moisture-retaining covers for flatwork toreceive flooring

71

Minimizing the Potential for Floor Failures

• Concrete

• Testing

• Moisture Mitigation

72

Tester Qualifications

• Proper Testing Equipment

• Experience Performing Tests

• Experience Interpreting Results

• ICRI Concrete Moisture Testing TechnicianCertification

– Training Seminar

– Written Examination

– Performance Examination

73

ASTM Moisture Test Standards

• ASTM F1869 – Standard Test Method forMeasuring Moisture Vapor Emission Rate ofConcrete Subfloor Using Anhydrous CalciumChloride

• ASTM F2170 – Standard Test Method forDetermining Relative Humidity in Concrete FloorSlabs Using in situ Probes

• ASTM F2420 – Standard Test Method forDetermining Relative Humidity on the Surface ofConcrete Floor Slabs Using Relative HumidityProbe Measurement and Insulated Hood

• ASTM F710 – Standard Practice for PreparingConcrete Floors to Receive Resilient Flooring

General Test Procedures

• Space at operational temperature andhumidity

• Three tests for first 1,000 ft2, one test for eachadditional 1,000 ft2 (10 yd3 truck covers 800ft2 at 4 in. thick)

• Do not concentrate test sites

75

ASTM F1869 – Moisture Vapor EmissionRate (MVER)

ASTM F1869: Procedures to Note

• Remove existing floor material

• Grind concrete surface

• Seal dome to concrete

• Test duration of 60 to 72 hrs

ASTM F1869: Results

• MVER = (52.91 * ΔM) / (A * T)

• MVER = lbs / 1,000 ft2 / 24 hrs (lbs)

• Maximum MVER = 3 lbs (per ASTM F710)

• Report should include the following:

– Any variations from the test standard.

– Ambient conditions during test.

– Identify any venting requirement.

ASTM F1869: Limitations of Test

• No documented scientific basis

• No calibration procedures or standardreference

• Only measures thin layer (1/2 in.) on surface

– Not a good indication of trapped moisture inlightweight concrete

ASTM F2170 – Internal Concrete RH

ASTM F2170: Procedures to Note

• Select appropriate depth for holes

– Slab Drying from Top Only: 40% Depthfrom Top of Slab

– Slab Drying from Top and Bottom: 20%Depth from Top of Slab

• Clean holes

• Seal sleeve

• Test duration of 72 hrs

ASTM F2170: Results

• RH = Water Vapor in Air (at a specific temp.)Maximum Water Vapor in Air (at same temp.)

• RH = %

• Maximum RH = 75% (per ASTM F710)

• Report should include the following:– Depth from top of slab, slab thickness,

“drying conditions.”

– Ambient temperature and humidity.

– Make and model of instruments used.

– Last calibration and calibration procedures.

ASTM F2170: Limitations of Test

• Newer method

• Limited thickness of slab

• Different probes give different results

Other Moisture Measuring Tools

ASTM F1869 vs. ASTM F2170

• So I conducted the tests properly, what dothe results mean?

ASTM F1869 vs. ASTM F2170

High RH Low RH

High MVER

Low MVER

ASTM F1869 vs. ASTM F2170

High RH Low RH

High MVER

Low MVER

• Average calculation not applicable, maximumvalue must be below limit.– Can consider breaking floor up into zones, but must be

clearly defined by floor, concrete pour, etc.

What Happens Next?

88

Moisture Mitigation

Minimizing the Potential for Floor Failures

• Concrete

• Testing

• Moisture Mitigation

89

Moisture Mitigation System

• We Recommend: Two-component, VOC compliant,low viscosity, 100% solids epoxyformulated as a vapor retarderagainst high moisture andalkalinity substrates (ASTMF3010)

• We Avoid: penetratingcoatings, water-basedmaterials, concrete admixtures

90

Moisture Mitigation

• Joint/Crack Treatment

– Manufacturerrecommended jointtreatment varies

91

Movement Joint Non-Movement Joint

Leveling Underlayment

• Required if using a water based adhesive

• Portland-cement-based (less than 13%gypsum content), self-leveling underlayment

– Primers

– Thicknesses

92

Case Studies

Case Study: Museum Warehouse

Blisters in Epoxy Coating

Liquid from Blister

Good Drainage on Site

No Issues with Uncoated Concrete

Blisters and Liquid under Epoxy Coating

Calcium Chloride MVER Tests

8.27

5.79

4.44

1.43

0.00

1.002.003.004.00

5.006.007.008.00

9.00

1 10 100 1000 10000

MVER vs. Hours after Coating Removal

Vapor Retarder over Existing Coating

Reinforced Topping Slab on New VaporRetarder

Curing of New Topping Slab

Application of New Coating on“Dry” Topping

Final Repair

Case Study: Elementary SchoolSlab-on-Grade

107

Flooring Deterioration

108

Existing Floor System

109

VAT

VCT

Floor Vent Pipes

110

Sub-Slab Construction

• Concrete floor slab is 5 in. thick• Sub slab soil is sandy-clay with 1 in. and

larger stones• Moisture content of the soil about 8% (dry

soil typically has less than 2% moisture)• No vapor retarder beneath concrete (to

depth of 17 in.)• Site drainage system functions

adequately• Water table at least six feet below

surface

111

Moisture Measurements

112

RoomMVER(lbs)

RH(%)

5 5.9 95

15 5.7 95

library 7.9 96

11 9.8 97

gym 8.2 92

Moisture Measurements

113

RoomMVER(lbs)

RH(%)

5 5.9 95

15 5.7 95

library 7.9 96

11 9.8 97

gym 8.2 92

Floor Venting System

• Direction of air movement through vents is intobuilding, regardless of roof-top vent fanperformance, so floor system receives outside air ona continual basis.– When outside air is warmer than floor, potential for

condensation within floor system exists.

– When outside air is cooler than floor, flooring system cancool, increasing potential for condensation to occur onsurface of flooring.

Buildings Mechanical System

• Interior dew point tracks with outside temperatureand humidity.

• Air flow is into building, drawing exterior humidity intorooms and corridors.

• Dew point occasionally becomes higher than floortemperature in late fall and in spring, potentiallycausing condensation on floor surface.

115

Sources of Moisture in and on Flooring

• From concrete, and soil beneathconcrete

• From roof venting system

• From open doors and windows

116

Repair Recommendations

• Remove flooring and tile to expose concrete surface(requires asbestos abatement)

• Shotblast concrete to remove residual adhesive• Seal surface of concrete with a topical moisture

mitigation membrane – including floor beneath cabinetsand heating units.

• Apply finish flooring system (leveling layer, adhesive, tile)• Adjust / replace doors and fixtures as needed• Repair openings left in roof from discontinued vents• Review mechanical system operation and balance

building– Install make-up air system to classrooms– Dehumidify air (either make-up or ambient)

117

Floor System Demolition

118

Concrete Surface Preparation

119

Floor Patching Requirements

120

Mitigation Coating Application

121

Finish Installation

122

Case Study: Wood Flooring in Condos

Floor System

1. Bamboo Strip Flooring

2. Strip Flooring to Underlayment Adhesive

3. Sound Attenuation Underlayment

4. Underlayment to Substrate Adhesive

5. Substrate

Failure Mechanism

• Bamboo swells (mostlyperpendicular to “grain”)due to change in moisturecontent after installation.

• System of soundattenuation underlaymentand adhesives cannotrestrain expansion.

• Underlayment/adhesivesystem fail at slabinterface.

• Bamboo floor buckles(“tents”) since bond tofloor had failed.

Stresses from Moisture Change

Conceptual cross section of installed flooring.

Increased moisture content causes flooring to swell. Swelling restrained by bond tosubstrate. Stresses in wood, underlayment and adhesive increase with increased

swelling.

Bond fails. Flooring allowed to swell and change length. Stresses in flooring are relieved.

Causes of Failure

• Bamboo is composite of bamboo fiberand adhesive which can expand andcontract with changes in moisture.– Acclimatization– Ambient conditions– Relatively low concrete slab moisture

• Sound isolation mat is not adequate tosupport bamboo.– Improper adhesive and adhesive application– Use of water-based adhesives– Allows expansion and contraction– Low tensile strength of mat

Mockup

• Three-ply, cross-grain, horizontal-laminated bamboo flooring (6 in. widestrip flooring planks).

• Urethane wood flooring adhesive.

• Moisture vapor protection and soundisolation barrier coating.

Mockup

Mockup

Case Study: Self Storage ConcreteComposition

Chemical Concrete Composition

132

Chemical Concrete Composition

Magnified Concrete – For Orientation

Sand

Aggregate

Cement

Typical ASR – Normal Light

Crack coming out of aggregatein perpendicular direction

Dark rim around aggregate

TYPICAL ASR – Thin Section, Colored by Polarized Light

Crack coming out of aggregatein perpendicular direction

Crack filled with gel

Crack in aggregateand filled with gel –

shown by pinkish color

The First Repair

The First Repair

The First Repair

Uh oh

Uh oh

The Second Repair

The Second Repair

The Second Repair

The Second Repair

Case Study: Coating in MaintenanceCenter

Delamination of Coating from Impact

Delaminated Coating Sample

Pull-Off Adhesion Tests

Pull-Off Adhesion Tests

Test No.Tensile Force

at Failure (psi)Plane of Failure

P-1 200 Between disc and adhesive

P-2 200 Cohesive within top layer of concrete

P-3 380 Between disc and adhesive

P-5 300 Cohesive within top layer of concrete

P-7 250 Cohesive within top layer of concrete

P-9 200 Cohesive within top layer of concrete

P-10 220 Cohesive within top layer of concrete

P-11 300 Cohesive within top layer of concrete

P-12 275 Cohesive within top layer of concrete

P-13 500 Between adhesive and concrete

P-15 300 Between disc and adhesive

P-16 50 Between adhesive and concrete

Concrete Petrography

Initial Recommendations

• Remove the coating system and aminimum of 5/16 in. of the surface of theslab.– Least aggressive form of surface preparation

that will remove the existing coating anddamaged surface layer of concrete

– Surface preparation techniques should beevaluated through mock-ups

• Coating system used is appropriate - itcan be reinstalled on a properlyprepared substrate.

Mockups

Remedial Options – Concrete SurfacePrep

• Shot Blasting

+ Removes coating and prepares concrete

– Causes damage to surface of concrete

• Scraping and Sand Blasting

+ Will prepare concrete without causingsignificant damage

– Two-step process to remove coating andprepare concrete

Remedial Options – Repair ConcreteSurface

• Gravity Fed Epoxy+ Easy to install

– May not fill all cracks

• Injected Epoxy+ Easier to install in smaller phased areas

– Labor intensive, time consuming, andineffective on small cracks

• Concrete grinding+ Can reliably remove all damaged concrete

– Time consuming due to required surfacerepairs

Remedial Options – Floor Finishes

• Tile (with uncoupling membrane)+ Easily phased, minimal moisture problems

– Aesthetic change, prone to impact damage

• Polished and Stained Concrete+ No curing time, high durability, no moisture

problems

– Poor resistance to staining, aesthetic change

• Epoxy Coating+ No aesthetic change, easily cleaned

– Must overcome concrete damage andmoisture levels

Mockups

• Level of shot blasting

• Gravity fed epoxymaterial

Mockups

Final Specification

• Shot blasting to ICRI CSP 3-5.

• Application ofmitigation/consolidation system diluted50% with acetone.

• Wait 48 hrs.

• Application of 100%mitigation/consolidation system.

• Wait 12 hrs.

• Application of epoxy coating system.

Repairs – Surface Preparation

Repairs – Epoxy Application

Repairs – Completed Coating

What’s Coming?

• Self-desicating concretes

• Other specialty concretes

• New moisture mitigation technologies,formulations, and formulation revisions

• Earlier and earlier application ofmoisture mitigation

• Waterproof and pH-proof adhesives

• Greener flooring materials

• Self-adhesive flooring materials

163

Summary

• Understanding moisture is critical to preventingfailure for flooring coverings and coatings onconcrete, especially with today’s water-basedand 100% solids adhesives and coatings.

• Limit the moisture in concrete by using a vaporretarder, controlling the mix design, andcontrolling the curing.

• The concrete slab is the substrate – design andconstruct it with that in mind.

• The flooring and adhesive type(s) dictaterequirements for the flooring and otherspecification sections.

• Include a moisture mitigation system in thespecification (base bid, add alternate, or unitprice) – surface preparation is key

This concludes The American Institute of ArchitectsContinuing Education Systems Program

Simpson Gumpertz & Heger Inc.

Thank you for your time.

QUESTIONS?

Section 033000 – Cast-in-Place Concrete

• Typical FF and FL Combinations and Descriptions

• Moderately Flat – FF25/FL20 – office building with carpet

• Flat – FF36/FL20 – shopping center or hospital public areawith thin-set coverings

• Very Flat – FF45/FL30 – very sensitive, includingwarehouses with air pallets

166

Rating

Slab-on-GradeSuspended Slabs

(shored)Suspended Slabs

(unshored)

OverallLocalMin.

OverallLocalMin.

OverallLocalMin.

FF25/FL20FF25/FL20 FF17/FL15 FF25/FL20 FF17/FL15 FF25 FF17

FF36/FL20FF36/FL20 FF24/FL15 FF30/FL20 FF24/FL15

FF30FF24

FF45/FL30 FF45/FL30 FF30/FL20--- ---- --- ---

Slab-on-Grade and Curling

Rebar near top of slab to prevent curlingand arrest cracking

Saw-cut control joint

Shrinkage-compensatingadmixture in concrete