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Understanding the Toilet Flange — Install New Flange

Intermediate6 hours

Part of project

How to Replace a Broken Toilet Flange · Step 4 of 7

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In this video

This step provides a detailed overview of the toilet flange, which is the fitting that connects the toilet's drain to the drainage pipe. The video showcases a 3-inch PVC flange that includes an integrated test cap, which is a convenient feature for pressure testing the drain system before the final toilet installation. The knockout cap can be removed later with a hammer and channel-lock pliers. The instructor explains the various slots and holes on the flange: four larger slots are for the toilet bolts that secure the toilet bowl to the flange, and eight smaller holes are for mounting the flange itself to the subfloor with screws. It is critical to align the toilet bolt slots parallel to the back wall for a straight toilet installation. The instructor also discusses the ideal height of the flange, which should sit on top of the finished floor, and explains how to use shims to achieve this height if installing over a thick flooring material like tile on a wood subfloor.

Goal: Plumbing Fixture Installation

  • To knock out the test cap, strike the center with a hammer and then use channel-lock pliers to grip and pull out the broken pieces.
  • Align the toilet bolt slots so they are parallel with the wall behind the toilet. This ensures the toilet will sit straight.

Used in this video

  • Hammer (brand: Unknown, Hammer Type: Claw hammer) — Knocking out the test cap on the toilet flange.
  • Channel-lock Pliers (brand: Unknown, Pliers Type: Slip-joint pliers) — Gripping and removing the pieces of the knockout test cap after it's been struck.
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FAQs

Is replacing a toilet flange a difficult DIY project for a beginner, and how long does it typically take?

This project is rated as intermediate due to the precision required for a leak-proof seal and the need to handle plumbing. While the estimated time is 6 hours, beginners should allocate a full day, as unexpected issues like subfloor damage can extend the duration significantly.

Do I really need all the specific tools and materials listed, or can I substitute some for this project?

Many essential tools like adjustable wrenches, a drill, level, and screwdrivers are critical. While some general tools might be substituted, using the recommended materials like a new PVC flange, primer, cement, and a quality wax ring with bolts ensures a durable, leak-proof repair. Avoid cutting corners on the sealing components.

What's the most common mistake people make when replacing a toilet flange, and how can I avoid leaks?

The most common mistake is not ensuring the new flange is perfectly level with and securely fastened to the finished floor, or improperly seating the wax ring. To avoid leaks, make sure the flange is flush and tight, and carefully set the toilet straight down onto the new wax ring without rocking.

What are the most important safety precautions I should take when replacing a toilet flange?

Always shut off the water supply to the toilet and completely drain the tank and bowl before starting any work. Wear disposable nitrile gloves for hygiene and consider eye protection when working with tools or chemical primers and cements. A tarp is also crucial for protecting your flooring from water or debris.

Transcript
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Alright, in this section we're going to take a look at roughing in a toilet. So first we're going to look at the toilet flange. This is the fitting that goes underneath of a toilet and this is for the drainage of the toilet. This is a three inch PVC toilet flange. It comes all PVC and it is this one since it's three inches made to have three inch glue up into the bottom of it. This one comes ready for testing. So this one is actually really good because you can see here in the center. There is a test cap right here that will knock out when it comes time to set the toilet so the waste will go down. And I'll show you how to do that when we go to set the toilet, but that actually knocks out with a hammer and a pair of channel locks. So when you go to set this toilet, you're going to drill a hole in the floor or you'll have a pipe coming up already through a slab where you installed it on a slab with this amount to a couple of things to note the slots here. You'll see there's four of them around the perimeter. This is where the toilet bolts will be installed that actually hold the toilet down to the flange. So the toilet bolt itself will slide into this square part and it will slide back into this notch and it will sit in this groove right here. And when you mount this flange, you definitely want to try your best to get this center line straight across with those two bolts because there's two bolts that hold the toilet down. And again, we'll look at that when we actually set one in one of the next classes. But the toilet bolts slide into this and they lock into these slots right here and you can use either one, but there's just opposite of each other for however you want to turn it. A couple of the things to note from this slide here is the mounting holes. This is where you will mount the screws or you'll mount the flange with screws to whatever subfloor that you're using. So there's eight holes for that to mount it to secure it so it locks it in place so it actually holds the toilet down. When we take a look at it from this view, this is a cross section of view of it. You can see where the three inch will glue into the hub here or the fitting. One of the things to take note of is your finished floor height. Ideally, in a perfect situation, this point right here, the flange, this distance from here to here is about three eighths of an inch. So ideally, the finished floor, when everything is set and done, will butt up to this flange about right at this point…

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