Flooring (C-15) · Lesson 6 of 7

Floor Transitions: Changes in Level, Thresholds, and Carpet Edges

"Floor Transitions: Changes in Level, Thresholds, and Carpet Edges" is lesson 6 of 7 in the Flooring (C-15) Learning Hub. It opens with "Stable, Firm, Slip Resistant Surfaces" and works through 5 short steps, then a worked example you can check yourself against.

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Steps in this lesson

  1. Stable, Firm, Slip Resistant Surfaces
  2. The Three Height Zones (11B-303)
  3. Doorway Thresholds
  4. Carpet and Floor Openings (11B-302.2, 11B-302.3)
  5. Egress Paths and Dwelling Doors

The worked example in the course applies this lesson to a realistic job in 5 steps, from "Door thresholds" through "Carpet edge".

What you'll be able to do

  • Explain the main idea of "Floor Transitions: Changes in Level, Thresholds, and Carpet Edges" in plain language you can use on the exam.
  • Apply this step with confidence: "Doorway Thresholds".
  • Apply this step with confidence: "Carpet and Floor Openings (11B-302.2, 11B-302.3)".
  • Apply this step with confidence: "Egress Paths and Dwelling Doors".
  • Test yourself on the worked example and the quick-check quiz inside the classroom.
Floor Transitions: Heights, Bevels, and Door ThresholdsTHREE FLOOR-HEIGHT CHANGES (side view)A 3/16 in: vertical, no edge treatmentB 3/8 in: bevel no steeper than 1:2run 3/4 inC 5/8 in: ramp required (not to scale)MEASURE, THEN CLASSIFYChangeZoneTreatment3/16 inup to 1/4 invertical OK3/8 in1/4 to 1/2 inbevel, 1:2 max5/8 inover 1/2 inramp (11B-405/406)Bevel run = 2 x rise = 2 x 3/8 = 3/4 in minDoor threshold: 1/2 in high max (11B-404.2.5)Carpet pile: 1/2 in max, edges trimmed(11B-302.2); trim meets 11B-303Sliding door to a dwelling unit: 3/4 in max(CBC 1010.1.6)A passes as is, B needs a 1:2 bevel with a 3/4 in run, C needs a rampDoorway thresholds stay at 1/2 in high or less; raised thresholds follow 11B-302 and 11B-303Source: 2025 CBC 11B-302.2, 11B-303.2 to 11B-303.4, 11B-404.2.5; 2025 CBC 1010.1.6.CC
The diagram for this lesson, exactly as it appears in the Learning Hub.

The first steps of this lesson

Step 1: Stable, Firm, Slip Resistant Surfaces

2025 CBC Section 11B-302.1 says floor and ground surfaces shall be stable, firm and slip resistant, with exceptions for animal containment areas and areas of sport activity. Chapter 11B applies to public buildings, public accommodations, commercial buildings and public housing, and Section 11B-403.2 sends walking surfaces on an accessible route back to 11B-302. Every transition strip, patch, and new floor on such a route is judged against these sections.

Step 2: The Three Height Zones (11B-303)

Section 11B-303.2 allows changes in level of 1/4 inch (6.4 mm) high maximum to be vertical and without edge treatment. Section 11B-303.3 says changes between 1/4 inch minimum and 1/2 inch (12.7 mm) maximum shall be beveled with a slope not steeper than 1:2. Section 11B-303.4 says changes greater than 1/2 inch shall be ramped and comply with Section 11B-405 or 11B-406. Measure the actual height difference where two flooring types meet; the sum of the thickness difference and any adhesive or underlayment build-up counts.

The remaining 3 steps, the worked example and the quiz are in the course. This is a preview. The full lesson, with the step-by-step explanations, a worked example and a quick-check quiz, is inside the classroom.

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