Concrete Moisture Calculator

The Concrete Moisture Calculator determines concrete moisture content, drying time, and readiness for flooring installation. Essential for construction professionals, flooring contractors, and quality control.

Modify the values and click the calculate button to use
Test Method
Concrete Age days
Slab Thickness mm
Water-Cement Ratio w/c
Ambient Temperature °C
Relative Humidity %
Flooring Type

Related Moisture Content Calculator | Drying Time Calculator | Relative Humidity Calculator

Understanding Concrete Moisture

Concrete moisture content is critical for flooring installation, coating application, and structural integrity. Excess moisture can cause flooring failures, coating delamination, and long-term durability issues.

Moisture Testing Standards

ASTM F2170 - In-Situ Relative Humidity

Method: RH probes inserted into concrete at 40% of slab depth

Accuracy: Most reliable for thick slabs

Time: 72-hour equilibration period

Limits: Typically 75-85% RH maximum for flooring

ASTM F1869 - Calcium Chloride Test

Method: Calcium chloride dish sealed to concrete surface

Duration: 60-72 hours

Units: Pounds per 1000 sq ft per 24 hours

Limits: Typically 3-5 lbs/1000 sq ft/24 hrs maximum

Acceptable Moisture Levels

Flooring Type Max RH (%) Max MVER* Notes
Epoxy Coating 75-80 3 Vapor barrier properties
Vinyl/LVT 75-85 3-5 Check manufacturer specs
Carpet 90 5 More tolerant
Hardwood 75 3 Very moisture sensitive

*MVER = Moisture Vapor Emission Rate (lbs/1000 sq ft/24 hrs)

Factors Affecting Concrete Drying

Mix Design Factors

Environmental Factors

Structural Factors

Drying Time Estimates

General Guidelines

Rule of Thumb: 30 days per inch of thickness (one-sided drying)

Two-Sided Drying: 15 days per inch of thickness

High w/c Ratio: Add 50-100% to base time

Low Permeability: May require 6+ months for thick slabs

Thickness Effects

Slab Thickness One-Sided Drying Two-Sided Drying Notes
100mm (4") 4 months 2 months Typical residential
150mm (6") 6 months 3 months Commercial standard
200mm (8") 8 months 4 months Heavy duty industrial

Moisture-Related Problems

Flooring Failures

Coating Problems

Accelerated Drying Methods

Environmental Control

Surface Preparation

Quality Control

Testing Frequency

Test Location Selection

Mitigation Strategies

Vapor Barriers

Moisture-Tolerant Systems

Economic Considerations

Cost of Delays

Prevention Benefits

Note: Concrete moisture testing should always follow established standards and manufacturer requirements. This calculator provides estimates - actual testing is required for critical applications. Consult with flooring manufacturers and testing professionals for specific project requirements.