Do Not Begin With Demolition

The first impulse after a floor failure may be to remove everything quickly and restore production. Demolition can destroy evidence needed to identify the cause, determine responsibility, select the repair, or support a warranty claim.

Before widespread removal begins, document the undisturbed condition, map the failure, preserve representative samples, review the project records, and identify appropriate testing.

Make the Area Safe

Failed flooring and coatings can create immediate hazards. Loose sheets, lifted edges, blistered coating, wet surfaces, exposed chemicals, and damaged concrete can affect workers and building occupants.

Initial Safety Actions

• Restrict access to the affected area.
• Mark loose, lifted, or slippery locations.
• Remove immediate trip hazards only after documenting them.
• Identify chemical or biological contamination.
• Evaluate electrical equipment exposed to water.
• Review ventilation and respiratory hazards.
• Determine whether mold, asbestos, lead, or other hazardous materials may be present.
• Establish dust, noise, waste, and traffic controls for investigation work.

Document the Undisturbed Failure

Create a record of what the failure looked like before materials were removed. Take overview photographs showing the complete room and close-up photographs showing the specific defects.

Include a ruler, scale, or location marker where useful. Record the date, time, environmental conditions, building operation, and recent events such as rain, flooding, washdown, HVAC shutdown, or chemical exposure.

Map the Following Conditions

• Blisters, bubbles, and craters
• Loose or hollow-sounding areas
• Peeling and delamination
• Efflorescence and salt deposits
• Darkened or damp concrete
• Soft, sticky, or discolored adhesive
• Cracks, joints, drains, and penetrations
• Exterior walls, doors, refrigeration, and HVAC outlets
• Previous repairs and patch boundaries
• Equipment, tanks, plumbing, and washdown areas

Determine the Failure Plane

The failure plane identifies the layer or interface where separation occurred. It is one of the most important pieces of evidence in a flooring or coating investigation.

Preserve Representative Samples

Samples can help identify the material, failure plane, contamination, coating thickness, adhesive condition, deposits, and blister contents. Preserve samples from both failed and apparently sound areas.

Label each sample with its location, date, orientation, collector, and description. Photograph the area before and after collection. Use clean tools and containers when chemical or blister-fluid analysis may be required.

Maintain a record of who handled each sample when litigation, warranty, insurance, or formal laboratory analysis is possible.

Review the Original Project Records

• Project specification and approved submittals
• Concrete placement, curing, and vapor-retarder information
• Original moisture and pH test reports
• Surface-preparation method and CSP records
• Repair, crack, joint, and penetration details
• Product technical data and safety data sheets
• Batch, lot, mix, and coverage records
• Environmental readings and daily reports
• Recoat, cure, and return-to-service times
• Manufacturer inspections or written approvals
• Change orders, exceptions, and owner directives
• Warranty documents and exclusions
• Maintenance, cleaning, chemical, and spill records

Missing records do not prove that an installation step was omitted, but they make it harder to demonstrate that requirements were satisfied.

Investigate the Moisture Source

Moisture may be coming from within the concrete, the ground, plumbing, process equipment, exterior drainage, cleaning operations, condensation, or groundwater. More than one source may be present.

Questions to Ask

• Does the failure become worse after rain?
• Does it follow cracks, joints, walls, drains, or plumbing?
• Is an effective underslab vapor retarder documented?
• Did the building experience flooding or roof leakage?
• Are floors washed down regularly?
• Do process lines, tanks, or equipment leak?
• Does the failure change with HVAC operation or season?
• Could condensation form on the slab?
• Is the area on grade, below grade, or adjacent to retained soil?
• Are water-filled cracks or active seepage present?

Testing the Failed Area

The investigation plan should match the suspected failure mechanisms. One moisture reading or one adhesion test rarely explains an entire failure.

Localized Repair or Complete Removal?

The repair scope should be based on the extent and mechanism of failure—not solely on the amount of visibly loose material.

Localized Repair May Be Appropriate When

• The cause is isolated and has been corrected.
• The surrounding system remains well bonded.
• The concrete is sound beyond the repair boundary.
• Moisture conditions are within the approved repair-system limits.
• The existing material is compatible with the repair.
• A durable transition can be created.
• The manufacturer approves the repair detail.

Broader Removal May Be Necessary When

• Failure is widespread or continuing to grow.
• Moisture affects the entire slab area.
• Adhesion is questionable beyond visible failure.
• The existing system is incompatible with the required repair.
• Contamination extends beyond isolated locations.
• The original surface preparation was inadequate.
• The membrane or primer is discontinuous across the floor.
• The complete assembly cannot be warranted as a patchwork repair.

Develop the Repair Scope in Writing

The repair specification should identify what is being removed, how far removal extends, how the substrate will be evaluated, what conditions require additional work, and which replacement system will be installed.

The Written Scope Should Address

• Work limits and sequencing
• Protection of occupants, equipment, and production
• Hazardous-material controls
• Removal method and required depth
• Waste handling and disposal
• Moisture-source correction
• Concrete repair and surface-strength criteria
• Surface preparation and required CSP
• Moisture, pH, adhesion, and environmental testing
• Crack, joint, drain, and penetration details
• Moisture-mitigation system
• Compatible primers, underlayments, adhesives, and coatings
• Mock-up and inspection requirements
• Cure, protection, and return-to-service requirements
• Documentation and warranty responsibilities

Removing the Failed System

Removal methods can include scraping, grinding, shot blasting, scarifying, chipping, milling, or combinations of methods. Select the method according to the material thickness, bond, concrete condition, contamination, facility restrictions, and required final profile.

Removal should continue until sound, acceptable substrate is exposed. Leaving a weak or incompatible layer in place simply moves the new system's bond line onto the old problem.

Removal Quality Concerns

• Smearing soft adhesive or contamination into concrete
• Polishing concrete with inappropriate diamond tooling
• Fracturing the concrete through excessive impact
• Leaving thin films in pores and low areas
• Damaging joints, drains, conduits, or embedded systems
• Spreading dust and contamination into operating areas
• Creating a profile too aggressive for the replacement membrane
• Removing evidence before required samples are collected

Repairing the Concrete

Removal may expose cracks, spalls, low areas, weak concrete, corroded reinforcement, incompatible patches, or deeper contamination. These conditions should be documented and repaired using materials approved for the moisture condition and replacement assembly.

The repair material may be installed below or above the mitigation membrane depending on the approved system. Materials placed beneath the membrane must tolerate the moisture exposure within the slab.

Do not use a moisture-sensitive patch beneath a high-performance mitigation membrane without written approval. The membrane cannot protect a patch from moisture entering from below.

Cracks and Joints

Determine whether each crack is dormant, moving, leaking, or structurally significant. Rigidly filling an active crack can transfer movement into the replacement coating.

Expansion and isolation joints should normally remain capable of movement. Construction joints and control joints require project-specific evaluation and detailing.

Active water entering through a crack or joint must be investigated before the replacement system is installed.

Installing Moisture Mitigation

When testing and the repair design indicate that mitigation is appropriate, install the approved system over clean, sound, properly profiled concrete.

Control mixing, working time, coverage, film thickness, pinholes, details, cure, and compatibility exactly as required. A repair project is not a reason to relax installation requirements.

Transitioning From New to Existing Material

Local repairs require a durable transition to the retained system. The repair edge may need to be saw-cut, tapered, abraded, cleaned, primed, or overlapped according to the approved procedure.

Feathering material to a thin, unsupported edge can produce early failure. The repair detail must account for system thickness, traffic, movement, moisture, and appearance.

Mock-Ups and Trial Repairs

A trial repair can confirm removal method, preparation, material handling, transition details, cure, appearance, and initial adhesion.

The mock-up should represent the actual failure condition and use the proposed production procedure. Record every material, batch, coverage, condition, and observation.

Short-term success does not reproduce years of moisture exposure or facility service, but an unsuccessful mock-up can prevent a much larger mistake.

Verifying the Repair

Return to Service

Cure time and return-to-service time are not always the same. A floor may support light foot traffic before it can withstand forklifts, chemical exposure, washdown, heavy equipment, thermal cycling, or full production.

Follow the most restrictive requirement among all system components. Protect the repair from early traffic, rolling loads, water, cleaning chemicals, and temperature extremes.

Repair Documentation

• Original failure photographs and floor map
• Samples collected and laboratory reports
• Moisture, pH, adhesion, and substrate-test results
• Failure-plane observations
• Identified or suspected moisture source
• Approved repair specification and changes
• Removal limits and methods
• Concrete conditions discovered during removal
• Repair materials, batches, quantities, and locations
• Surface preparation and accepted CSP
• Environmental readings
• Membrane coverage, inspection, and repair records
• Compatibility approvals for every system layer
• Cure and return-to-service records
• Final acceptance and warranty documents

Common Repair Mistakes

• Beginning removal before documenting the failure
• Assuming moisture is the cause without testing
• Repairing only the visibly loose material
• Leaving weak or contaminated concrete in place
• Using an incompatible patch beneath the mitigation membrane
• Rigidly filling moving cracks and joints
• Installing mitigation over active leakage
• Using a different replacement system without compatibility review
• Ignoring edges and transitions between old and new material
• Covering membrane pinholes or soft spots
• Returning the repaired floor to service too early
• Failing to document hidden conditions and approved changes

Contractor Repair Checklist

• The area has been made safe.
• The undisturbed failure has been photographed and mapped.
• Representative samples have been preserved.
• The failure plane has been identified.
• Original project and maintenance records have been reviewed.
• The moisture source has been investigated.
• Required testing has been completed.
• Localized versus complete removal has been justified.
• The repair scope and responsibilities are written.
• Hazardous materials and contamination are addressed.
• Unsound and incompatible materials have been removed.
• Concrete repairs and joints follow approved details.
• The mitigation and replacement system is compatible.
• Each hidden layer is inspected before covering.
• Cure and return-to-service requirements are enforced.
• Final records and acceptance documents are complete.

Knowledge Check

Technical References

Use the editions required by the project specification and follow current written instructions issued by the repair and replacement-system manufacturers.

• ASTM D714 - Standard Test Method for Evaluating Degree of Blistering of Paints.
• ASTM D7234 - Standard Test Method for Pull-Off Strength of Coatings on Concrete Using Portable Pull-Off Adhesion Testers.
• ASTM F2170 - Standard Test Method for Determining Relative Humidity in Concrete Floor Slabs Using In Situ Probes.
• ASTM F1869 - Standard Test Method for Measuring Moisture Vapor Emission Rate of Concrete Subfloor Using Anhydrous Calcium Chloride.
• ASTM F3010 - Standard Practice for Two-Component Resin Based Membrane-Forming Moisture Mitigation Systems for Use Under Resilient Floor Coverings.
• ICRI Guideline No. 310.2R - Selecting and Specifying Concrete Surface Preparation for Sealers, Coatings, Polymer Overlays, and Concrete Repair.
• ICRI Guideline No. 710.3 - Guide for the Mitigation of Moisture in Concrete Floor Slabs.
• OSHA 29 CFR 1926.1153 - Respirable Crystalline Silica standard for construction.
• Current technical data sheets, installation instructions, safety data sheets, repair details, compatibility statements, and warranty documents issued by the specified repair, mitigation, coating, adhesive, underlayment, and flooring manufacturers.

These references provide technical guidance but do not replace the project specification, applicable regulations, laboratory analysis, manufacturer requirements, or evaluation by a qualified professional. Final failure conclusions and repair decisions must be based on the complete body of available evidence and actual site conditions.