Can A Toilet Fall Through The Floor? (Here’s What You Can Do..)

It is inevitable that your toilet will sooner or later leak.

Of course, many things cause toilets to leak occasionally, including a lousy wax ring, a crack in the porcelain, or bolts coming loose.

Whatever the reason, when your toilet starts leaking, the subfloor absorbs the water, weakens, and begins to sag.

That said, Can A Toilet Fall Through The Floor?

Absolutely YES. Although most houses today have more robust floors to withstand weights and every day, sometimes not so typical, abuse, it is possible for toilets to fall through the floor, particularly if the house is built on a conventional foundation with a crawl space beneath.

Normally, toilets are designed to hold an average human, withstand normal abuse, and most other things like gravity. However, when the floor weakens due to a slow, insidious leak, it should be no surprise that your toilet can potentially fall through the floor.

If you have a sinking bathroom floor because of a leaky toilet, read on to find more about leaking toilets and how you can fix a rotten subfloor around your toilet.

What Would Cause A Toilet To Fall Through The Floor?

The primary cause for toilets falling through the floor is a damaged subfloor, which is usually due to exposure to moisture on an ongoing basis.

This is usually due to a slow, constant leak which causes the floor to eventually decay.

Considering that your manufactured home subfloor is made from organic material, prolonged exposure to moisture causes the subfloor to weaken, making your toilet prone to sinking.

While other things like termites and rodents can interfere with the structural integrity of your subfloor, it is less likely that they will do anything big enough to weaken your subfloor to the point it cannot withstand normal abuse.

That’s why overexposure to moisture is considered the apparent cause.

Regarding the causes for toilets to inadvertently fall through the floor, make sure to keep an eye on the following causes of a leaky toilet.

1. Loose Tee Bolts

Tee bolts connect your toilet to the floor, securing it in place while ensuring it is snug.

Over time, the hardware loosens due to force from general use, which can cause leaks.

2. Worn Out Wax Ring

While its corrosion-resistant properties make the wax ring an excellent option, it can wear out over time; therefore, failing to do its job properly.

With a worn-out wax ring, it is apparent that your floor will weaken due to rings.

3. Clogged Drain Line

A clogged drain could cause the wax ring to wear out prematurely resulting in leaks.

4. Damaged Bowl

Although in rare cases, you can have a damaged bowl.

Bowls are usually made of porcelain or ceramic, all prone to cracking. As such, your bowl can crack due to prolonged heavy use and start leaking.

If the porcelain or ceramic has cracks, it is best to replace the entire toilet.

While leaks in the bathroom might seem like a small problem, they are the common cause of toilets falling through the floor.

To ensure that your subfloor doesn’t give up the ghost at that particular moment when you visit the bathroom, make sure to regularly confirm the structural integrity of your floor.

How To Fix A Rotten Subfloor Around Your Toilet

Whether your bathroom foundation is sinking or you don’t notice until the toilet falls through the floor, you must fix that rotting wood and other subfloor elements to continue enjoying life in your manufactured home.

Here are steps handy in repairing the subfloor under your toilet.

1. Identify The Leak

When fixing a spoiled floor, the first thing you should do is identify what exacerbated rotting in the subfloor under your toilet.

This will help ensure that you replace the defective part of the subfloor and fix the leak.

While identifying a leak when the entire subfloor is already wet and rotted can be tricky, you will eventually find it provided you are keen on details.

You should then turn off the water supply via the line valve behind the toilet.

2. Remove The Toilet

Disconnect the flexible water line and remove the excess water from the toilet (via plunger).

Unscrew the bolts at the bottom of the bowl that secures your toilet to your home’s foundation and lift up to remove it.

Notably, toilets are too heavy, so you may need someone to help you lift yours safely.

Next, scrape away the last remnants of the wax ring sticking on the mounting flange, then remove the flange from the drain.

If your toilet has fallen through the floor, separate its components and clear the space before you start to fix the foundation

3. Cut Away The Rotten Wood

First off, you want to inspect how far the rotted subfloor extends from where the bowl was sitting.

The defective portion should extend about one foot unless the toilet leaked for a prolonged period without your knowledge.

Identify the circumference of the rotted area, cut a few inches beyond the rotted wood, and discard all rotted wood.

It is advisable that you cut such that the two sides of the cut run parallel to the floor joints over the center of the joists.

4. Flame The Opening

Measure the open area and cut pieces of 2-by-6-inch timber into pieces that can design two frames that fit between the subfloor joists and under the cuts.

These frames will become nailers for repair.

Make sure that there is a frame fitting on either side of the flange.

Screw the timber pieces together and then to the subfloor joists.

Use 2 ½-inch exterior-grade screws and a power screwdriver to accomplish this step.

5. Repair The Floor

Guided by the measurements of the openings, trim a ¾ inch plywood to match the opening.

Secure the plywood into place with 1 ½-inch exterior-grade screws and make sure they go through the subfloor joists.

Install the flange and then the flooring. Depending on your flooring, you are more likely to need new flooring for the entire bathroom.

6. Reinstall The Toilet

After repairing your floor, the next thing is to reinstall your toilet. If your porcelain has at least a crack, it is best to buy a new toilet.

During installation, make sure to set the wax ring properly and tighten the tee bolts.

Once you are done, you can continue using your toilet on a firmer foundation.


Although not likely, your toilet can fall through the floor.

Hopefully, after reading this post, you gained insights into what you can do when your toilet starts sinking into the crawl space.