CSMT Exam Domains 2026: Complete Guide to All 5 Content Areas

How the Five Content Areas Fit Together

The Concrete Slab Moisture Testing Technician (CSMT) program, administered by the International Concrete Repair Institute (ICRI), certifies technicians who test concrete floor slabs before flooring is installed. The credential is formally titled ICRI Concrete Slab Moisture Testing Technician-Grade 1. If you are still orienting yourself, our explainer on what CSMT certification is covers the basics. This article goes deeper into the five examination-reference topics and how to prepare for each.

The five areas are not random. They describe a complete field workflow for answering one question: is this slab ready to receive flooring? Each method answers a different slice of that question:

• Is the surface chemistry acceptable? That is the pH question (ASTM F710, Section 5.2).
• How much moisture vapor is leaving the surface? That is the calcium chloride question (ASTM F1869).
• What is the moisture condition inside the slab? That is the in situ probe question (ASTM F2170).
• Where are the wet spots, quickly and without drilling? That is the electronic meter question (ASTM F2659).
• Will the surface absorb water the way flooring adhesives and patching materials need it to? That is the porosity question (ASTM F3191).

Understanding that each standard exists to answer a different question is the single best way to keep them straight. Candidates who memorize procedures in isolation tend to blur them together; candidates who know why each test exists can reason their way through unfamiliar scenarios.

What the Domain List Is (and Is Not)

ICRI lists these five headings as examination-reference and preparation topics, including the applicable annexes and appendices of each standard. They are unweighted. ICRI does not publish a percentage breakdown assigning, say, a quarter of the questions to one topic and a fifth to another. They also should not be read as an exhaustive blueprint of everything the written exam might touch, because the examinations also cover the education session delivered as part of the certification course.

A practical consequence: because no weighting is published, you cannot safely skip a topic on the theory that it is "worth less." The performance portion also requires you to physically run all five tests, so every topic carries real consequences. For a candid look at what this means for difficulty, see how hard the CSMT exam is.

Domain 1: ASTM F710 and Section 5.2 pH Testing

ASTM F710 is the standard practice for preparing concrete floors to receive resilient flooring. For this credential, the examination-reference emphasis is on Section 5.2, pH testing. Surface alkalinity matters because highly alkaline concrete surfaces can interfere with adhesives and flooring materials, and a pH reading is a quick, inexpensive way to flag a problem before installation.

Because pH testing is the simplest of the five methods, candidates sometimes under-prepare for it. Do not. On a written exam, simple topics are where careless misses happen, and on the performance check you are expected to carry out each procedure correctly without coaching.

Domain 2: ASTM F1869 Calcium Chloride Testing

ASTM F1869 covers measuring the moisture vapor emission rate (MVER) of a concrete subfloor using anhydrous calcium chloride. In practice, a dish of calcium chloride is weighed, sealed under a dome on the prepared slab surface for a set period, then reweighed. The weight gain reflects the moisture vapor leaving the surface over that period, and the result is converted into an emission rate.

Expect to be comfortable with both the "why" and the arithmetic. Practice the calculation by hand until it is routine, and rehearse the physical sequence of the test so you can perform it cleanly in front of a judge.

Domain 3: ASTM F2170 In Situ Relative Humidity Probes

ASTM F2170 determines relative humidity in concrete floor slabs using in situ probes. Rather than sampling the surface, this method places probes in holes drilled into the slab so the readings reflect conditions within the concrete itself. Many flooring manufacturers and specifiers rely on this type of reading because moisture deeper in the slab is what ultimately drives the long-term risk to finished floors.

Of the five topics, F2170 is often the one where understanding concepts matters most. Questions can ask what should happen when conditions are not ideal, so know the reasoning behind each requirement and not just the requirement itself.

Domain 4: ASTM F2659 Electronic Moisture Meters

ASTM F2659 is a preliminary evaluation of the comparative moisture condition of concrete, gypsum cement and other floor slabs and screeds using a non-destructive electronic moisture meter. The keywords are preliminary, comparative and non-destructive. A meter helps you survey a large area quickly, compare one location with another and find suspect zones, all without drilling or placing kits.

Domain 5: ASTM F3191 Water Absorption (Porosity)

ASTM F3191 covers the field determination of substrate water absorption, also called porosity, for substrates that will receive resilient flooring. This topic addresses a different concern from the moisture-content methods above. It asks how readily the surface takes up water, which relates to how adhesives, patching compounds and other installation products will behave when applied to that substrate.

Because F3191 is the newest-feeling topic for many technicians, it is also where experienced field people sometimes have the thinnest background. If your hands-on history is mostly calcium chloride and probes, give this domain extra deliberate attention.

Side-by-Side Comparison of the Five Methods

This table condenses what each reference topic is for. It is a memory aid, not a substitute for the standards supplied to registered candidates.

How the Exam and Performance Check Work

The CSMT credential has two gates, and passing one does not excuse the other. Understanding the structure shapes how you should study the five domains.

1. The written examination. The published schedule allocates one hour to the written exam. The 3-4 hour education session that precedes it is instructional, not exam time. ICRI has not published a verified question count or numeric passing threshold that we can cite, so be wary of any source quoting specific figures. For more on this gap, see our discussion of the CSMT passing score.
2. The performance check. You must successfully perform all five tests before a qualified judge, without coaching. This is assigned as a separate one-hour appointment.

Eligibility is also worth knowing before you invest in study time. You need ICRI-approved previous hands-on testing experience, or a prequalification waiver earned through participation in the Demonstration and Workshop. Our guide to CSMT requirements and eligibility walks through how to qualify.

Retakes and the one-year window

If you fail the initial written examination, it must be retaken in full. If you fail only certain performance methods, just those methods are repeated. In either case, the retake must occur within one year or the full certification course must be repeated. Plan your first attempt as though it is your best shot, because a failed attempt carries real scheduling and cost consequences.

Fees, recertification and what the online course is not

Published 2026 full-course fees, which include the education session and the demonstration and workshop, are USD 1,050 for ICRI members, USD 1,350 for non-members and USD 510 for verified student members. Certification lasts five years. First recertification is written-exam-only at USD 495 for members or USD 595 for non-members, and a failed first-recertification written exam carries its own six-month re-examination deadline before the full course is required. Second and later recertifications require the full certification course, at USD 695 for members or USD 895 for non-members. See our full CSMT certification cost breakdown for planning.

Sequencing Your Preparation by Domain

You do not need a generic study template here. What helps is ordering the five topics so that each one builds on the last and the hardest hands-on material gets the most repetition. One reasonable sequence:

Layer practice questions in each week so you are testing recall right after learning a topic. For a broader plan, our CSMT study guide covers how to structure your overall preparation, and our CSMT cheat sheet is a handy final-review companion. You can also use the CSMT practice test site to check your recall across all five topics before the course.

Frequently Asked Questions

Mastering these five topics, and respecting that two separate gates stand between you and the credential, is the clearest path to certification. If you are weighing whether the investment makes sense for your career, our analysis on whether the CSMT certification is worth it is a good next read.