NCIDQ IDIX Exam Prep: Free Study Guide and 20 Practice Questions

The IDIX (Interior Design Implementation Exam) replaced PRAC in 2026. Start this NCIDQ IDIX exam prep guide with the priority map, then work the 20 original practice questions below it.

What IDIX covers: your priority map

The weights are CIDQ's, from the official IDIX blueprint. The right-hand column is our plain-English version of what each domain asks you to do.

The blueprint's topic bullets show what can be tested. Counting them doesn't tell you how many questions each topic gets.

IDIX practice questions

These 20 questions are original and unofficial. We wrote them for the 2026 IDIX blueprint, and they are not CIDQ questions. They sample all five domains in rough proportion to the weights. They are not a full-length exam, and your score on them is not a scaled score or a pass prediction.

They practice skills used in all four official item formats, not the exam interface itself. Matching questions stand in for drag-and-place, and labeled regions stand in for hot spots. Two vignettes group four related questions each, much like the scenario sets CIDQ describes. The code calculations supply the rules and inputs you need; the real exam provides a code-reference document. See the CIDQ handbook, p. 19 and code index, p. 1.

Standalone questions (9–20)

Check your results

Count correct answers by domain, then go back to every miss and every lucky guess. With three to six questions per domain, a score here points you toward a topic to review. It is not a measure of your readiness.

For this set, each numbered question counts once. A matching question is correct only when every placement is correct; there is no partial credit in this tally. Keep blank or incomplete responses separate from completed incorrect answers. These are practice-set rules, not CIDQ's scoring rules.

How to study each IDIX domain

Practice one habit across all five IDIX domains: connect a requirement to the drawing, schedule or spec that carries it out, then check that the documents agree. Each domain below has a method and a concrete thing to produce while you study.

Codes and Life Safety

Work every code question in the same order: context, then rule, then exception, then units, then check. Pin down the occupancy and exactly what's being asked before you touch a ratio.

Keep gross and net areas straight; the factor tells you which to use. Calculate mixed functions separately, then add them where egress paths combine (Question 9). Trace a route before you measure it, because the common path and the full travel distance are different lengths (Question 10). For plumbing, read the facility arrangement before you split the population (Question 5).

For accessibility, check whether the building is new or existing first. ICC A117.1-2017 sets bigger turning and clear-floor spaces for new buildings (Question 2).

CIDQ's blueprint FAQ says "life safety" covers more than this, including fire alarms, fire separation, fire suppression, flammability, slip resistance and toxicity. Candidates also need conceptual knowledge of ANSI, NEC and NFPA, and of when standards like ASHRAE, ASTM, BIFMA, ETL, OSHA and UL apply.

Produce: a one-line code-check record for each problem. Note the context, code section, inputs, result and what the result doesn't settle.

Integration and FF&E

Choosing something that looks right isn't the skill being tested. Documenting that it meets the project's actual criteria is. Build a small requirements-versus-evidence table covering dimensions, services, performance data and installation conditions, and eliminate options criterion by criterion (Questions 3 and 8).

Match the rating to the problem: NRC for absorption, STC for airborne isolation, IIC for impact (Question 15). Show takeoffs in whole buying units, not just area (Question 16).

Produce: a selection matrix that names the exact criterion each rejected option fails, and one takeoff with every rounding step visible.

Construction Documents

This is the heaviest domain at 32%, so give it the most practice time. Use the view that answers the question, then cross-check:

• Plans locate things horizontally.
• Elevations show a face and its heights.
• Sections show what happens through a cut.
• Details resolve one local condition.

Skills to drill:

• Read heights from one shared datum (Question 6).
• Add every layer in a stack (Question 12).
• Follow a callout to the right detail and sheet (Question 11).
• Catch a demolition marking that contradicts scope (Question 14).
• Ask for listing evidence before assuming a changed assembly keeps its rating (Question 13).

Produce: an annotated drawing with the controlling dimensions and tags marked, plus one sentence naming the mismatch and the requirement behind it.

Consultant Drawing Coordination

Compare documents in a fixed order:

1. Confirm you're looking at the same room, current revisions and a common datum.
2. Compare locations and quantities.
3. Log the issue and route it to the discipline the project assigns.

Matching room numbers don't prove a three-dimensional fit. Two elements can share a footprint and still clash in height (Question 20). Changed fixture counts ripple into other disciplines' schedules and circuits (Question 7).

Produce: an issue log with five columns: location, affected documents, conflicting values, responsible lead, and the evidence that would close the issue.

Construction Specifications and Schedules

Trace each requirement through its plan tag, schedule entry and spec section. A missing entry isn't permission to guess, and two entries that disagree have to be resolved, not picked between (Questions 4 and 19).

Know the three-part format: General, Products, Execution (Question 18). Know the main spec types too:

• Descriptive specs describe the material.
• Performance specs state results.
• Reference-standard specs point to a published standard.
• Proprietary specs name products. They're open if substitutions are allowed and closed if they're not.

Source: CSI, Specifying Methods—Proprietary Specifying 101.

Produce: one requirement traced from tag to schedule to spec clause, with any gaps flagged before issue.

Your 8-week IDIX study plan

Assumes: about five hours a week (five one-hour blocks) for eight weeks, or roughly 40 hours. This is our editorial plan, not a CIDQ requirement. It's built for someone who already works on construction documents. If your role is mostly schematic design or FF&E selection, stretch the Construction Documents weeks.

Error log columns: question, what I chose, why it seemed right, the requirement or source I missed, the corrected method, and when I'll review it next. Tag each miss as one of these:

• missed condition
• wrong code edition
• drawing-reference error
• arithmetic or units
• missing evidence
• wrong role assumption

On a second pass, a better score may only mean you remember these questions. Explaining why is the real test.

If your exam is this month: compress the plan into the study time you have. Work through the 20 questions, then reread the domain sections behind your misses and lucky guesses. Learn the break and calculator rules below, and confirm your appointment details in your MyNCIDQ account.

How IDIX works on exam day

Exam eligibility is separate from a state or province's licensing or registration requirements; check the applicable jurisdiction through CIDQ's eligibility guidance.

Two of these rows change how you should study:

• The code-reference images won't be there. The exam gives you the code text without its images, so learn the A117.1 clearance diagrams and dimension figures well enough to picture them. Practice working from code text, not from memorized tables. Individual exam questions can still include exhibits.
• Breaks lock earlier questions. Before you step away, finish and review every question you've opened, because you can't go back to it afterward.

What changed from PRAC

• Name and scope. PRAC is gone. IDIX covers design development and construction documentation only (About the Exams).
• Format. No case studies. All three NCIDQ sections now use the same four item types, with short vignettes (blueprint FAQ).
• Codes. The basis is now the 2021 I-Codes plus A117.1-2017. Watch for the larger new-building accessibility dimensions.
• Dropped topics. BOMA calculations are no longer tested. CIDQ says you should still know high-level square-footage ideas like rentable vs usable area (FAQ Q7).

Older PRAC notes can still teach useful concepts. Organize your study around the current blueprint, though, not the old case-study structure.

IDIX FAQ

Is the IDIX open book? No books are allowed (handbook, p. 26). But CIDQ supplies a code-reference document with the listed code text, without its images, as part of each question. CIDQ's code index lists which chapters and sections, so study those.

I passed PRAC already. Do I need to take IDIX? CIDQ says sections you've already passed don't have to be retaken because the blueprints changed, as long as your exam application is still active (blueprint FAQ, Q13). If the applicable eligibility period expires before you complete the required sections, CIDQ's reapplication policy says passing scores are voided.

Do I have to take IDFX before IDIX? Once approved for the relevant sections, you can take them in any order. IDFX-only approval does not authorize an IDIX attempt; Route 2 candidates need the subsequent application and work experience (CIDQ application routes). If you prefer to follow the design phases, CIDQ notes the order is IDFX, then IDIX, then IDPX (blueprint FAQ, Q14).

Does CIDQ have IDIX practice questions? CIDQ's study materials page lists separate free practice-question links for IDFX and IDPX, but no separate IDIX practice-question link as checked October 13, 2026. It also links a demo exam for exploring item formats, the code index and a reference list. CIDQ doesn't create or endorse prep courses.

What about study materials passed around by other candidates? Use legitimate study materials, not recalled or reconstructed exam content. CIDQ's candidate agreement prohibits studying from exam content reconstructed from memory, and it requires candidates to report it (handbook, pp. 41–42 and 46).

Sources and independence

Exam facts on this page were last verified October 13, 2026, against these CIDQ documents:

• IDIX Blueprint (2026 and forward)
• NCIDQ Candidate Handbook, revision 1225
• About the Exams
• Exam Codes index
• Exam Reference Materials (November 3, 2025)
• New Exam Blueprints FAQs
• Study Materials
• Eligibility

Technical points in the practice questions rely on these:

• ICC publications for the 2021 IPC §403.1.1, 2021 IBC means of egress and A117.1-2017 significant changes
• UL Solutions on wood panels in rated assemblies
• USG on acoustic ratings
• CSI SectionFormat and UFS 1-300-02 on specification format
• AIA A201-2017 and the A503 guide on contract documents
• Colorado State University's drawing requirements as a real-world documentation example

All project data in the questions is fictional and supplied for the exercise. AI assistance was used in drafting and in this source-and-consistency check; this is not a credentialed professional review. See our methodology for the distinction.

Preparing for more than IDIX? See the NCIDQ exam prep guide.

To check eligibility or schedule, go to CIDQ directly: eligibility · scheduling.

By the Castleport Test Prep Editorial Team.

Castleport Test Prep is an independent exam prep publisher. We are not affiliated with, endorsed by or approved by the Council for Interior Design Qualification (CIDQ). NCIDQ, IDIX, IDFX and IDPX are used only to identify the exams they describe, and trademarks belong to their respective owners. The practice questions on this page are original and unofficial, not actual exam questions. Nothing here guarantees passing, certification or licensure.