Presentation on theme: "Presented By: Mike Mudrick 2012 ICRI Carolinas Chapter Fall Convention Coating Failures, Causes, Preventative Measures & Repairs Executive Development."— Presentation transcript:
Presented By: Mike Mudrick 2012 ICRI Carolinas Chapter Fall Convention Coating Failures, Causes, Preventative Measures & Repairs Executive Development Center 1241 Military Cutoff Rd #A, Wilmington, NC RESIDENCE INN FRIDAY OCTOBER 12 th 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 Transmission A COMMON OCCURANCE IN THE FLOORING INDUSTRY In Gas Form Diffusion Action Vapor Static Pressure Measured in lb/1000 ft 2 /24 hr. (MVER)
DIFFERENCES BETWEEN GAS 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 SPEAKING VAPOR 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 SYSTEM An Open Slab System is the most challenging condition for a topical moisture & pH suppression system as moisture within the concrete will typically rise above the originally tested levels over time.
WHERE VAPOR EMISSION PROBLEMS APPEAR SLABS ON GRADE SLABS ABOVE GRADE SLABS BELOW GRADE
SOME COMMON CAUSES OF VAPOR 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: N o 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/yd 3 (Type I, II, …..) ~3,200 lb aggregates/yd 3 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/yd 3
a.Total WATER in concrete mix = 34 gal/yd 3 b. REQUIRED: WATER for hydration of cement ~35% = 12 gal/yd 3 c. RESULT: ~65% surplus WATER needs to evaporate = 22 gal/yd 3
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?!?!
How Is Moisture Vapor Emission Measured? Calcium Chloride Test Kit ASTM F 1869 3 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.
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 Probes Pros 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
WHERE CAN VAPOR EMISSION PROBLEMS APPEAR? SLABS ON GRADE
HOW DOES 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?!?! V olatile O rganic C ontent 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 ft 2 or Below 75% RH Risk Installing the Floor System? Pretend It Is Not A Problem? Run Away & Hide? NO!
APPLY A QUALITY SURFACE APPLIED VAPOR SUPPRESANT WHEN: MVER Is Greater Than 3 or 5 lbs OR 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 Penetrants Reactive penetrants are fluid applied treatments designed to penetrate the concrete surface and react chemically with the concrete. The goal of such treatments is to reduce the moisture vapor emission rate (MVER) and to bind up soluble alkali such that high pH levels are not experienced at the concrete/adhesive interface. The most common reactive formulations used for moisture & pH suppression are based 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 risk approach to topical moisture and pH suppression. 2. Cementitious Densification Modified cementitious overlays are intended to isolate the concrete surface from adhesives or coatings applied above. Such systems are intended to lower moisture transfer and restrict soluble alkalis within the concrete sub-floor from reaching the adhesive/overlay interface but can be inconsistent in efficacy.
Various Vapor Suppression Systems 3. Sealers Fluid applied sealers are available to help reduce moisture transfer and isolate the concrete 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 Coatings Hybrid epoxy-based or epoxy-modified coatings, specifically designed for high moisture/pH conditions, reduce the Moisture Vapor Emission Rate (MVER) and act as an isolation barrier to keep solutions of highly alkaline salts within the concrete from 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 the coating. When that becomes necessary the materials and processes to follow should be approved by the manufacturer of the suppressant system. 5. Dispersement Membranes Dispersement membranes were historically one of the first approaches to topical moisture suppression that experienced a reasonable measure of success. Such systems utilize a special fabric adhered to the surface of the concrete which provides a lateral avenue for water vapor to diffuse. These membranes are only for floating systems. 6. Combination Systems Several companies utilize a combination or “Cocktail” approach where two or more of 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 SUCCESSFUL VAPOR SUPPRESSANT INSTALLATIONS
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
Sample IdentificationCore #1Core #2 Sample Depth (mm - BTC*)0-3 mm3-5 mm0-3 mm3-5 mm IONIC CONSTITUENTCONCENTRATION (ppm) Sodium (Na)1410109011601140 Potassium (K)3500261010801050 Sulfate (SO4)2940469037702690 Chloride (Cl)18011040 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