Commercial Building Inspector B2Roof Ceiling ConstructionMedium

An inspector is evaluating a roof assembly with a new skylight installation on a commercial building. The skylight has a maximum dimension of 48 inches and is not designed as a walkable surface. According to IBC, what is the minimum height above the roof surface that a protective screen must extend around the skylight opening if the skylight is not protected by a curb or guardrail?

  1. A48 inches
  2. B42 inches
  3. C60 inches
  4. D36 inches
Show answer & explanation

Correct answer: B. 42 inches

IBC 2405.3 requires skylights and other roof openings to be protected from falling by a guardrail, a curb at least 4 inches high, or a protective screen. If a screen is used and the skylight is not designed to be walked upon, the screen must extend a minimum of 42 inches above the roof surface.

Why the other options are wrong

  • A. 48 inches is a greater height than required, offering more protection but not the minimum.
  • C. 60 inches is excessively high and not the code minimum for this application.
  • D. 36 inches is typically the minimum height for a guardrail in other applications, but not for skylight screens.

Skylight Protective Screen Height

The minimum height above the roof surface that a protective screen must extend around a non-walkable skylight opening, as specified by the IBC, to prevent falls.

  • 42 inches minimum height.
  • Applies to non-walkable skylights.
  • Alternative to curb or guardrail.

Memory trick: Skylight screen, 42 inches seen, keeps workers safe and keen.

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