Presented By: Mike Mudrick

2012 ICRI Carolinas Chapter Fall Convention

  Coating Failures, Causes, Preventative Measures & Repairs

Executive Development Center1241 Military Cutoff Rd #A, Wilmington, NC

RESIDENCE INN FRIDAY OCTOBER 12th 2012

Vapor Moisture Transmission In the

Construction Industry

Moisture Activity In Concrete CAN BE ENCOUNTERED EITHER

IN:

• In Liquid Form• Capillary Action• Hydrostatic

Pressure • Measured in psi.

OR

Moisture Vapor TransmissionA COMMON OCCURANCE IN THE FLOORING

INDUSTRY

• In Gas Form• Diffusion Action• Vapor Static

Pressure• Measured in

lb/1000 ft2/24 hr.• (MVER)

DIFFERENCES BETWEENGAS FORM & LIQUID FORM

Vapor Emission (GAS) Pressures:• Humid gas passing through the capillaries of the concrete

with minimal pressure, very little water, and will dry out when surface is not covered.

Hydrostatic (WATER) Pressures:• Generally moderate to high pressure, measured in PSI,

saturates the concrete, moves laterally, and remains constantly wet.

FLOORING FAILURES DUE TO

MOISTURE VAPOR EMISSION

Photo courtesy of Construction Technology Laboratories, Inc."

Acrylic Based VCT Tile Adhesive Failure

Failure of a Polyurethane Adhesive Due to

Moisture Vapor Emission

Example running track

Failure of an Epoxy Mortar Overlay Due To

Moisture Vapor Emission

Failure of Trowel Down Epoxy Coating Due to

Moisture Vapor Emission

Failure of Thin Film Epoxy Coating Due to

Moisture Vapor Emission

All Result In Lost $$$ Increased Liability

The Common Denominators?Probably Could Have Been

Avoided!!

GENERALLY SPEAKINGVAPOR EMMISSION PROBLEMS

CAN BE CATAGORIZED IN ONE OF TWO WAYS

1. Concrete Drying Issues “Closed Slab or Above Grade

Situations”

2. Chronic Diffusion Issues “Open Slab Situations”

A Closed Slab System is where an PERMANENT VAPOR BARRIER or non-perforated metal decking is

in place directly beneath the concrete. In a Closed Slab System the only source of moisture is free-water originating from within the concrete itself.

CLOSED SLAB SYSTEM

OPEN SLAB SYSTEMAn Open Slab System is the most challenging condition for a topical moisture& pH suppression system as moisture within the concrete will typically rise above theoriginally tested levels over time.

WHEREVAPOR EMISSION PROBLEMS

APPEAR

• SLABS ON GRADE

• SLABS ABOVE GRADE

• SLABS BELOW GRADE

SOME COMMON CAUSES OFVAPOR EMMISSION PROBLEMS

• OLDER BUILDING Without Any Under Slab Vapor Barrier

• OLDER BUILDING With a Damaged or Deteriorated Under

Slab Vapor Barrier

COMMONLY OVERLOOKED SITUATIONS LEADING TO

POTENTIAL VAPOR MOISTURE TRANSMISSION PROBLEMS

• Renovation Or Reconfiguration Of Existing Space

• NEW CONSTRUCTION With A Compromised (Direct Contact) V.B.

or Fill Saturated Before Slab Pour

(Indirect Contact)

GENERALLY IGNORED SITUATIONS LEADING TO

POTENTIAL VAPOR MOISTURE TRANSMISSION PROBLEMS

Renovation Or Reconfiguration Of Existing Space

• NEW CONSTRUCTION With Compromised (Direct Contact) V.B.

• Fill Saturated Before Slab Pour (Indirect Contact) V.B.

• FAST TRACK/NEW PROJECT: No Time to Wait for Concrete to Fully Dry

Reasons Achieving Proper RH& or MVER in New Construction Can Be

Difficult

2. WATER Of Convenience In The Fresh Concrete Mix

1. Concrete Or Fill Moisture Events

Amount Of WATER In Fresh Concrete

Example: A simple 6-sack concrete mix consists of

• 564 lb cement/yd3 (Type I, II, …..)

• ~3,200 lb aggregates/yd3

• Water for mixing, placing & hydration of cement

• Additives (superplasticizer, air entrainment, etc.)

W/C (water/cement ratio): 0.5 assumed

• Typical Amount of WATER: 0.5 x 564 lb = 282 lb

= 34 gal/yd3

a. Total WATER in concrete

mix = 34 gal/yd3

b. REQUIRED:

WATER for hydration of cement ~35% = 12 gal/yd3

c. RESULT:

~65% surplus WATER needs

to evaporate = 22 gal/yd3

Rule Of Thumb For Concrete Drying Time:

AT LEAST ONE MONTH PER 1” OF THICKNESS

(Will More Than Double In Winter)

Lightweight Concrete Mix Designs Dry At Rate 2 Times Longer Than Normal

Concrete

ALWAYS TEST TO BE SURE!!!

Isn’t Concrete Is DRY In 28 Days?NO!! Concrete Is Only CURED In 28

Days!Not Acceptable RH%

Not Under 3 to 5 lbs of MVER

WHAT IS DRY CONCRETE ANYWAY?!?!

Concrete Drying Times

How Is Moisture Vapor Emission Measured?

Calcium Chloride Test Kit

ASTM F 18693 Test Kits For The First 1000 S/F of Floor & 1 Additional Test

Kit For Each Additional 1000

S/F

Example: 7000 S/F =

9 Total Test Kits

CALCIUM CHLORIDE TEST ASTM F-1869

Measured in Pounds, of the Amount of Water Emitted from 1000 sq.ft. of Concrete Over 24 hours. (8 lbs = 1 gallon) NOT PSI…..

Proper Testing Requires 1 test per 1000 sq.ft. With a Minimum of Three Tests.

Space MUST Be “Climate Controlled” 48 Hours Prior to Kit Placement and Conditions Be Stable Throughout the Test.

The Surface Should be Ground, Clean and Remain “Open” 24 Hours Prior to Placement. Tests Require 62 to 70 hours.

Improperly Performed Calcium Chloride Tests

X

How Is Moisture Vapor Emission Measured?

Another New Test Method Is Currently Being Used:

ASTM F 2170 Test Method For Determining Relative Humidity In Concrete Floor Slabs Using In-Situ ProbesPros

Precise, accurate

Can be quickly re-measured

Not AS influenced by ambient conditions

Cost effective

Easy to track drying

Proven accuracy

Relative Humidity Probes

ASTM 2170

R. H. Probe Hole Depth 40% Of Slab Thickness

5” Thick Slab x .40” = 2 Inches Deep

Drill & Clean Hole, Insert R. H. Probe

Allow R.H. Probe to Acclimate as Required by Manufacturer Before Obtaining Readings

WHERECAN VAPOR EMISSION PROBLEMS APPEAR?

• SLABS ON GRADE

SLABS ON GRADE

Indoors

Outdoors

WHERECAN VAPOR EMISSION PROBLEMS APPEAR?

• SLABS ON GRADE

• SLABS ABOVE GRADE

SLABS ABOVE GRADE

Concrete on Non-Vented Metal Deck

Structural Concrete Components

Rehabilitation Or Remedial Projects

HOWDOES VAPOR

EMISSION CAUSE FLOORING

SYSTEMS TO FAIL?

Moisture Movement Through Interior Slabs On

Grade

VAPOR EMISSION Varies Throughout The Slab Itself

May Also Fluctuate During Different Times Of Year

Moisture Vapor Emission TRANSPORTS MINERALS & CONDENSATES AT

SURFACE

SOLUBLE METAL IONS

• Calcium Hydroxide: “Free Lime”• Potassium Hydroxide: “Caustic”• Sodium Hydroxide: “Unstable”

• Result: Dissolved metal ions raise the pH levels in the “solution” allowing a chemical attack on the organic compounds.

WHY NOW…. I Never Had Problems Before?!?!

Volatile Organic Content

REQUIREMENTS CHANGED IN THE LATE1990’s

The Real Issue Is High Ph

NEW GENERATION OF PRODUCTS DO NOT PERFORM WELL IN HIGH pH ENVIRONMENTS

pH Scale is Logarithmic

• pH 7 is Neutral• pH 7 and Lower is Acid• pH 7 and Higher is Alkaline

• A pH of 13 compared to a pH 7:

1 MILLION Times More Alkaline!!

• Adhesive Warranty Limits: pH 8.2 to 9

How Should One Proceed When MVER Is Not Within The Required

3 or 5 lbs/24 hr*1000 ft2 or Below 75% RH

•Risk Installing the Floor System?

•Pretend It Is Not A Problem?

•Run Away & Hide?

NO!

APPLYA QUALITY SURFACE APPLIED VAPOR

SUPPRESANT WHEN:

MVER Is Greater Than 3 or 5 lbsOR

Relative Humidity % Is Too High

IF HIGH MVER or RH% IS IGNORED YOU RISK SUFFERING COSTLY

FAILURES & REPAIRS

Various Vapor Suppression Systems

Currently there are 6 major system categories or material methods being marketed to

mitigate a high moisture or pH condition in concrete sub-floors. Treatments range

from single coat applications to multi-stage systems that combine two or more

categories of materials.

1. Reactive PenetrantsReactive penetrants are fluid applied treatments designed to penetrate

the concretesurface and react chemically with the concrete. The goal of such

treatments is toreduce the moisture vapor emission rate (MVER) and to bind up soluble

alkali suchthat high pH levels are not experienced at the concrete/adhesive

interface.The most common reactive formulations used for moisture & pH

suppression arebased on sodium silicate, potassium silicate or lithium silicate.

Before giving consideration to a silicate-based, reactive penetrant one must have

thorough knowledge of the concrete composition and degree of surface carbonation.

Concrete mixtures that contain pozzolanic materials such as Fly Ash or Slag can

reduce available reactive material within the concrete and thus lead to incomplete

reaction of the silicate-based treatment. Concrete that is more than superficially

carbonated may produce a similar result. Not only will un-reacted silicates not

achieve the desired reduction in the moisture vapor emission rate (MVER) but they

can inhibit the bond of subsequent flooring or coating applications.Reactive penetrants, as a stand alone treatment, are considered a very

high riskapproach to topical moisture and pH suppression.

2. Cementitious DensificationModified cementitious overlays are intended to isolate the concrete

surface fromadhesives or coatings applied above. Such systems are intended to lower

moisturetransfer and restrict soluble alkalis within the concrete sub-floor from

reaching theadhesive/overlay interface but can be inconsistent in efficacy.

Various Vapor Suppression Systems

3. SealersFluid applied sealers are available to help reduce moisture transfer and

isolate theconcrete from the adhesive applied above. Most sealers have warranty limits between 8 & 12 lbs or less and low ph stability. Therefore sealers

should be limited for closed slab systems where the demands and required performance is limited.

4. Specialty CoatingsHybrid epoxy-based or epoxy-modified coatings, specifically designed for

highmoisture/pH conditions, reduce the Moisture Vapor Emission Rate (MVER)

and actas an isolation barrier to keep solutions of highly alkaline salts within the

concretefrom reaching the subsequently applied adhesive or coating.

One, two and three coat systems are available. Some systems may require multiple coats to achieve sufficient mil thickness on very aggressively shot

blasted concrete.Additional leveling or cementitious substrate material may be required

over thecoating. When that becomes necessary the materials and processes to

follow should be approved by the manufacturer of the suppressant system.

5. Dispersement MembranesDispersement membranes were historically one of the first approaches to

topicalmoisture suppression that experienced a reasonable measure of success.

Suchsystems utilize a special fabric adhered to the surface of the concrete

whichprovides a lateral avenue for water vapor to diffuse. These membranes are

only for floating systems.

6. Combination SystemsSeveral companies utilize a combination or “Cocktail” approach where two

or moreof the systems discussed above are combined, but this approach is usually

cost prohibitive

DEFICIENCIES OF INFERIOR SURFACE APPLIED VAPOR SUPPRESSANTS

1. MANY VAPOR SUPPRESSANTS CAN ONLY PROTECT UP TO 8, 10 or 12 LBS MVER (NOT FOR OPEN SYSTEMS)

2. FEW VAPOR SUPPRESSANTS CAN WITHSTAND 25 LBS OF MVER

3. STILL LESS ARE 1-COAT SYSTEMS! 2-COAT & 3-COAT SYSTEMS ARE AVAILABLE….BUT WHY?!?

4. BEWARE!!! MANY DO NOT PERFORM IN HIGH ph ENVIRONMENTS OF 13 TO 14

5. HAVE MOISTURE SENSITIVE CHARACTERISTICS

Desired Capabilities Of Quality Surface Applied Vapor Suppressants:

• Must Have Ability To Be Applied To “Fresh” or Old Concrete

• Must Withstand Constant pH 13 – 14 (Normal pH of fresh concrete is 12 – 13) (Aged concrete has a pH 8 – 10)

• Must Provide Proper pH On Surface For Flooring Applications (Neutral = 7)

• Must Tolerate High or Unknown MVER

• Moisture Insensitive Formulation (Damp Surfaces OK!)

HOW MOISTURE RETARDING EPOXY COATINGS WORK

V. B.

Epoxy Vapor Suppressant Penetration

Microscopy Showing Penetration Of The Vapor Suppressant

Vapor Suppressant Thickness

Vapor Suppressant Penetration

STEPS TO SUCCESSFULVAPOR SUPPRESSANT

INSTALLATIONS

ALWAYSEvaluate & Diagnose Existing

Floor

TEST FOR SUCCESS• Extract Core Samples From Both..

Affected & Unaffected Areas

• Analyze Cores In Lab Under Scanning Electron Microscope (SEM)

• Analyze Cores Using Ion Chromatography

• Analyze Cores Using Infra Red Spectro Photometer

Example of Test Cores

Sample Identification Core #1 Core #2

Sample Depth (mm - BTC*) 0-3 mm 3-5 mm 0-3 mm 3-5 mm

IONIC CONSTITUENT CONCENTRATION (ppm)

Sodium (Na) 1410 1090 1160 1140

Potassium (K) 3500 2610 1080 1050

Sulfate (SO4) 2940 4690 3770 2690

Chloride (Cl) 180 110 40 40

Example of Ion Chromatography Test Results

Example of Infrared Spectroscopy Test Results

• Core #1 (MI#28014-01C); 0-3 mm BTC The amount of organic extractable residue comprises approximately 11,100 ppm (1.110%) of the concrete mass. The IR spectrum of the residue indicates the presence of alkyd and polyester resin material.

• Core #1 (MI#28014-01A); 3-5 mm BTC The amount of organic extractable residue comprises approximately 8940 ppm (0.894%) of the concrete mass. The IR spectrum of the residue indicates the presence of alkyd and polyester resin material.

• Core #2 (MI#28014-02A); 0-3 mm BTC The amount of organic extractable residue comprises approximately 16800 ppm (1.680%) of the concrete mass. The IR spectrum of the residue indicates the presence of alkyd and polyester resin material.

• Core #2 (MI#28014-02C); 3-5 mm BTC The amount of organic extractable residue comprises approximately 9,390 ppm (0.939%) of the concrete mass. The IR spectrum of the residue indicates the presence of alkyd and polyester resin material

• .* Note: ''BTC' = Below the Top surface of the Core

Surface Preparation!

ACID ETCHING?

ABSOLUTELY NOT!!!

Proper Surface Preparation

Steel Shotblasting

Proper Surface Preparation

Grinding

Proper Surface Preparation

Scarifying

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   CSP- 2 CSP- 3 CSP- 4

CSP- 5 CSP- 6 CSP- 7 CSP- 8

Concrete Surface Profiles

X

Degrease If Needed!

Remove All Contaminants

Proper Surface Preparation

Remove Excess Water & Puddles

Mix Thoroughly & Spread Suppressant at Prescribed Rate

Back Roll To Assure A Uniform System Mil Thickness

SUCCESSFUL APPLICATION

RECIPE FOR SUCCESS

• Professional Mitigation Team• RH or Calcium Chloride Testing• Select A Quality Mitigation System• Substrate Core Testing• Proper Substrate Preparation

AND

Call On Your Local

ICRI Carolinas Chapter Professionals

THANK YOU!

QUESTIONS?