How to Fix A Bathroom Floor That Is Rotting

  • By: Peter Allen
  • Date: 08/18/2021
  • Time to read: 5 min.

A spongy or rotten floor in the bathroom can be hazardous. You will feel it soft or going underfoot whenever you step over the rotten floor. When it happens, you will see rotten wood underneath the floor as you peel off the floor surface.

At this point, you may be interested to know how to fix a bathroom floor that is rotting.

You have to pry off the rotten floor part with the hammer and replace it with a new one if the floor joists are still unaffected. Also, you have to wipe off the debris and mess from the surface before you can actually replace the rotting floor with a new one.

The process is time-consuming and often laborious. Hence, it is suggested that you prepare yourself before getting into the replacement task.

How to Fix A Bathroom Floor That Is Rotting

When a wooden floor starts rotting, you will immediately see mold and mildew growth around it. Also, you should observe discoloration of the floor. This is high time you start the rotten bathroom floor replacement task with immediate effect.

Step 1: Follow the Safety Measurements

Replacing a rotting bathroom floor isn’t an easy task by any means. Hence, you must understand the process thoroughly and all the materials essential for the floor removal and replacement. It will ease out the replacement process.

While replacing the top-level surface of the bathroom floor, you may also need to replace the subfloor underneath it. At the worst, you will have to replace the joists too.

When you observe a soft floor or musty smell in the bathroom, it means you must remember the subfloor for betterment. It is laborious and nasty work.  Thus, you may often turn towards a professional if you aren’t comfortable with the clean-up steps.

When you replace the top surface, joist, and subfloor, make sure they have the precise measurement. It will help you in the perfect fitting of the replaced floor. It is crucial for a sound structure inside the bathroom and around the toilet for comfier movement.

While removing the rotting floor, you may feel a stinky smell coming out from the subfloor or underneath it. Thus, ensuring proper ventilation will be of great benefit. Also, removing the tiles and wooden stocks from the floor will generate massive sawdust.

You should wear a facemask to safeguard your eyes and ears from the sawdust. Also, you may want to use a goggle to protect the eyes from any flying particles during the replacement process.

Step 2: Remove the Rotten Bathroom Floor

Once you are ready with your essential elements and have taken proper safety measurements, it’s time to dive deep into the floor removal process. Before you start removing the rotting floor, ensure the following two things-

  1. Always turn off the water supply line in the bathroom and toilet. Otherwise, it runs the risk of flooding the remaining floor only to enhance your labor.
  2. You should also switch off the bathroom circuit breaker. It will ensure your safety from electric shocks.

You will need a crowbar or claw hammer. Use it to pry off the old and rotting tiles or hardwood or laminated pieces from the floor. Also, you might need a scoring tool or carpet cutter. It will depend on what type of material you will remove from the floor.

For a wooden floor, you have to score the edges to remove it easily.

Lastly, remove the subfloor underneath the rotting top-level bathroom floor. It is necessary because the subfloor is most likely to be damaged too.

After you have removed the top floor, you should check the joists around it. If you see any mold and mildew growth or water damage on the joists, be ready to replace it too. It will need even more labor and time on your part.

Step 3: How to Replace A Rotting Bathroom Floor

Once we are ready with the removal of the rotting floor, it is time to begin the replacement of the floor with a new one.

For this step, we are assuming that the floor joists are in good condition and won’t need replacement. Firstly, start by cleaning the entire surface to remove any debris and dust. Use a vacuum cleaner to accumulate the dust and debris for a proper reinstallation of the floor surface. You have to ensure that there is no lingering dust on the bathroom floor.

Next, you have to choose the right subfloor material for an installation. It varies according to the floor material in the bathroom. You may follow these tips-

  1. Apply underlayment as the subfloor for vinyl, laminate, and hardwood bathroom floor.
  2. For the concrete floor, use the recommended subfloor material or ask a professional.

Now, cut a piece of floor material that will easily fit into the removed surface. Use a measuring tape to measure the essential floor size accurately. Then, use a circular saw to cut it precisely. Also, use sandpaper to smoothen the edges. It ensures a better fit of the installed floor.

Use a power screwdriver to attach the screws with the joists. If you have used multiple lumbers on the wooden surface, you have to attach them tightly with several screws. After you have set the floor properly, use a coat of leveling compound around the edges.

What to Do with The Toilet in The Rotting Floor Bathroom?

At times, you may see the floor is rotting just around the toilet. Things will get tricky during this condition. You have to remove the toilet first and then replace the rotting floor. For this, please switch off the toilet water supply and flash it until it gets empty. On either side of the toilet, you will see one hold-down bolt.

Use a screwdriver or adjustable wrench to remove the bolt. Then, remove the toilet and follow our above-mentioned instructions to replace the subfloor and floor.


This is our detailed discussion on how to fix a bathroom floor that is rotting. You have to be extremely cautious so that you don’t damage the remaining parts of the floor while replacing the already rotten floor sections in the bathroom.

Also, the fitting must be rugged, so you don’t feel it weak while walking. A misfit subfloor and top-level floor will ruin the overall aesthetic of your bathroom. Also, it is most likely going to cause you injury, which isn’t expected either.

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