Skip to main content

Set Closet Bolts and Wax Ring — Installing the New Toilet Flange: Securing a Leak-Proof Seal

Beginner4 hours

Part of project

Toilet Flange Replacement & Installation: A DIY Guide · Step 2 of 2

Helpful?

In this video

With the new flange installed and secured, the plumber prepares to mount the toilet. He inserts two brass closet bolts into the keyway slots on opposite sides of the flange. He uses plastic retaining washers to hold them upright and centered. Next, he takes a new wax ring, which has a plastic horn to help guide waste, and places it firmly over the drain opening on top of the flange.

Goal: Toilet Repair (Base Leak)

1.2M views2.2K41 seconds
This Old House

2.2M subscribers

View Channel

FAQs

Is replacing a toilet flange truly a 'beginner' DIY project, and can it realistically be done in 4 hours?

While categorized as beginner, this project requires careful attention to detail, especially during toilet removal and flange installation. The 4-hour estimate is achievable for someone with basic DIY experience, but unexpected issues like rusted bolts or subfloor damage can significantly extend the time. Always plan for potential delays and have extra materials on hand.

Do I need specialized tools beyond the screwdriver, level, adjustable wrench, and putty knife listed in the guide?

For removing old flanges, you might need additional tools. A hacksaw, oscillating multi-tool, or grinder can be essential for cutting stubborn plastic or metal flanges. If dealing with a severely corroded cast iron flange, a cold chisel and hammer might be required. A wet-dry vacuum is also very helpful for cleaning debris from the drainpipe.

What should I do if I discover significant subfloor damage around the old flange after removal?

Significant subfloor damage must be repaired before installing the new flange to ensure a stable and leak-proof seal. Carefully cut out the damaged section and replace it with new plywood or cement board, ensuring it is level with the surrounding floor. Improperly repaired subfloor can lead to rocking toilets and future leaks.

How can I ensure a leak-proof seal when installing the new toilet flange?

First, make sure the subfloor surface where the flange sits is clean, dry, and level. Dry-fit the flange to confirm it sits flush with the finished floor. Secure it with the appropriate #10 3” wood screws, but be careful not to overtighten and crack the flange. The proper wax ring (or waxless seal) will then create the final watertight connection with the toilet.

Transcript
Hide

I'm just doing each bolt a little bit at a time so I drive that rubber gasket down evenly. Okay, so now we have a nice tight seal between the flange and the bend and the flange is right down tight to the floor so that's good. Now we need to make a connection between the flange and the toilet. For that we use this. It's called a closet bolt as an oval shaped at the base and that goes into a keyway right here. Okay, and we hold that right to the center point right there. Another one on the opposing side. And now we need to make a seal with this wax ring that's going to connect to the bottom of the toilet and that keeps any sewer gases coming into the building and also keeps any water from leaking from the base of the toilet. Okay, now I want to line up those bolts.

Auto-generated transcript. May contain errors.