CSLB C-36 Plumbing ContractorFixture and Appliance InstallationMedium

A plumber is installing a wall-mounted toilet. The rough-in dimensions specify a distance of 15 inches from the finished wall to the center of the waste outlet. However, due to existing structural elements, the actual waste pipe stub-out is 17 inches from the finished wall. Which of the following is the most appropriate solution to accommodate this discrepancy?

  1. ARelocate the structural elements to align with the rough-in.
  2. BInstall the toilet as is, as a 2-inch difference is negligible.
  3. CUse a standard closet flange and force the toilet into position.
  4. DInstall an offset closet flange.
Show answer & explanation

Correct answer: D. Install an offset closet flange.

An offset closet flange is specifically designed to adjust for discrepancies in the rough-in dimension of a toilet's waste outlet, allowing the toilet to be installed correctly without altering the main waste pipe or structural elements.

Why the other options are wrong

  • A. Relocating structural elements is typically a costly and complex undertaking, often impractical for a minor rough-in adjustment.
  • B. A 2-inch difference is significant and will prevent proper installation and sealing of the toilet.
  • C. Forcing the toilet will likely damage the toilet, the flange, or create a leaky seal, leading to future problems.

Offset Closet Flange

A type of toilet flange with an eccentric opening that allows for minor adjustments (typically 1.5 to 2 inches) in the rough-in measurement of a toilet's waste outlet.

  • Used to correct rough-in discrepancies.
  • Avoids costly repiping or structural alterations.
  • Ensures proper toilet installation and seal.

Memory trick: When the rough-in's off, the offset flange will scoff at the scoff.

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