A wobbly toilet is more than just an annoyance—it can lead to serious plumbing issues if left unaddressed. Fortunately, fixing a wobbly toilet is a manageable do-it-yourself (DIY) project for most homeowners. In the video above, This Old House plumbing and heating expert Richard Trethewey walks you through diagnosing and fixing an unstable toilet.
Common Causes of a Wobbly Toilet
Several factors can contribute to this issue. Identify what’s causing the instability so you can choose the best repair method and prevent it from happening again.
Loose Closet Bolts
Closet bolts are responsible for securing the toilet to the floor flange. Over time, these bolts can loosen, causing the toilet to wobble. Tightening these bolts is often the simplest cause to address and should be your first point of inspection.
Damaged Wax Ring
The wax ring creates a watertight seal between the toilet and the floor flange. If this ring becomes damaged or compressed, it can lead to instability and potential leaks. This can be easily resolved by replacing the ring.
Uneven Floor
In some cases, the floor beneath the toilet may be uneven, causing the toilet to rock. This is particularly common in older homes where floors may have settled over time. Addressing this issue may require shimming the toilet or leveling the floor itself.
Damaged Flange
The toilet flange is the fitting that connects the toilet to the drainpipe. If this flange becomes damaged or corroded, it can cause instability. Repairing or replacing the flange may be necessary to prevent wobbling.
Tools and Materials
Before beginning the repair process, gather the following items:
- Adjustable wrench
- Caulk (optional)
- Level
- Mini hacksaw
- New closet bolts and caps
- New wax ring or flexible rubber gasket
- Putty knife
- Toilet shims
Level- Open ended adjustable wrench
- Putty knife
- Mini hacksaw
Steps To Fix a Wobbly Toilet
Follow these steps to stop the rocking:
- Shut off the water supply to the toilet and flush to empty the tank and bowl.
- Disconnect the water supply line from the toilet.
- Remove the decorative caps covering the closet bolts at the base of the toilet.
- Loosen and remove the nuts and washers from the closet bolts.
- Carefully lift the toilet off the floor and set it aside on a drop cloth.
- Inspect the wax ring and flange for any damage or wear.
- Clean the flange and surrounding area thoroughly.
- Install new closet bolts into the flange.
- Place a new wax ring or flexible rubber gasket onto the flange.
- Carefully lower the toilet back onto the flange, aligning it with the new closet bolts.
- Use a level to check if the toilet sits evenly on the floor.
- Insert toilet shims under the base of the toilet if necessary to level it.
- Secure the toilet by tightening the nuts onto the closet bolts, alternating sides for even pressure.
- Cut off any excess length from the closet bolts using a mini hacksaw.
- Replace the decorative caps over the closet bolts.
- Reconnect the water supply line and turn the water back on.
- Flush the toilet and check for any leaks or continued wobbling.
Addressing an Uneven Floor Below Toilet
In some cases, as seen in Trethewey’s demonstration, the floor beneath the toilet may be uneven. This requires additional steps for stable installation.
Using Multiple Shims
When dealing with a severely uneven floor, you may need to use multiple shims to properly level the toilet. Place shims at various points around the base of the toilet until it sits level and doesn’t rock.
Trimming Excess Shim Material
After placing the shims and securing the toilet, use a utility knife to carefully trim away any excess shim material that extends beyond the base of the toilet. This creates a cleaner, more finished look.
Applying Caulk
While not always necessary, applying a bead of caulk around the base of the toilet can help conceal the shims and provide an extra layer of stability. However, some plumbers prefer to leave the back portion uncaulked to better detect leaks.
Replacing the Toilet Wax Ring
A key step in fixing a wobbly toilet is replacing the wax ring. This creates a watertight seal between the toilet and the floor flange. Here’s how to replace it:
- Remove the old wax ring and clean the flange thoroughly.
- Center the new wax ring on the flange, with the plastic sleeve facing up.
- Lower the toilet carefully onto the new wax ring, making sure it’s properly aligned.
- Press down firmly on the toilet to compress the wax ring and create a proper seal.
In the video, Trethewey demonstrates using a flexible rubber gasket as an alternative to traditional wax rings. These gaskets can be more forgiving and easier to work with, especially for DIY installations.
Inspecting and Repairing the Toilet Flange
A damaged or corroded toilet flange can be a hidden cause of toilet instability. Here’s how to inspect and address flange issues.
Checking Flange Condition
Once the toilet is removed, carefully inspect the flange for any signs of damage, such as cracks or corrosion. A damaged flange will need to be repaired or replaced to ensure a stable toilet installation.
Flange Repair Options
For minor flange damage, repair kits are available that can reinforce the existing flange. In cases of severe damage, it may be necessary to replace the entire flange, which is a more involved process that may require professional assistance.
Upgrading the Toilet to a Foam Gasket
While traditional wax rings are effective, you may want to upgrade to a foam gasket. Foam gaskets provide a more resilient seal and are easier to install without the mess of wax. They can be especially useful in homes where the toilet might need to be removed and replaced multiple times for other repairs.
Preventing Future Wobbling
To maintain a stable toilet and prevent future wobbling, follow these tips:
- Periodically check and tighten the closet bolts to keep them secure.
- Avoid using harsh cleaning products that can damage the wax ring or flange.
- Address any signs of instability promptly to prevent more serious issues from developing.
