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Install New Pipe and Gasket — Install the New PVC Flange

Intermediate

Part of project

How to Replace a Cast Iron Toilet Flange with PVC · Step 7 of 10

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In this video

Insert a rubber donut gasket into the now-clean hub of the cast iron fitting. Place the new PVC pipe into the gasket. To fully seat the pipe, place a block of wood on top of the pipe to protect it and strike the wood block firmly with a hammer until the pipe is pushed securely into the gasket.

Goal: Install New Pipe Section

Used in this video

  • Hammer (Hammer Type: Claw hammer)Tapping the new pipe into place.
  • Wood BlockProtecting the end of the PVC pipe while hammering it into the fitting.
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FAQs

How difficult is replacing a cast iron toilet flange with PVC, and how long should I expect it to take?

This project is rated as intermediate. While it doesn't require specialized plumbing skills, removing the old cast iron and lead/oakum seal can be physically demanding and time-consuming. Expect it to take anywhere from half a day to a full day, especially if you encounter unexpected issues like a stubborn old flange.

What specialized tools are absolutely essential for removing the old cast iron flange and its lead/oakum seal?

Beyond basic household tools, you'll definitely need a cold chisel and a hammer for breaking up the old cast iron and carefully removing the lead/oakum seal. A shop vacuum is also crucial for quickly cleaning up debris and ensuring the cast iron pipe is spotless before installing the new flange.

What are the most important safety precautions I should take when demolishing the old cast iron flange and seal?

Always wear heavy-duty safety glasses to protect against flying fragments and a respirator (like the Honeywell R95) to avoid inhaling dust and potential lead particles from the old seal. Heavy-duty gloves are also essential to protect your hands from sharp edges and the demolition tools.

What's a common mistake when installing the new PVC compression flange, and how can I avoid it?

A common mistake is not thoroughly cleaning and deburring the inside of the cast iron pipe after removing the old flange. Any rough edges, rust, or debris can compromise the compression seal of the new PVC flange, leading to leaks. Ensure the pipe's interior is smooth and completely clean for a watertight fit.