How to Replace a Rotting Bathroom Floor

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There are several things you should consider when replacing a rotting bathroom floor.
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If your bathroom floor is rotting, you may be able to tell in several ways. The floor could move underfoot or be soft to the touch. Your floor could also smell or have discoloration, visible mold or mildew, and Modern Bathroom says warped walls can also be an indicator. No matter how you become aware that your floor is rotting, replacing it is essential for your health and safety.


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Important Safety Considerations

Before attempting to replace a rotting floor yourself, you should thoroughly understand all elements of the process. When you replace the top-level floor surface, you'll likely also need to replace the subfloor and possibly even the floor joists beneath, depending on the extent of the damage. Budget Dumpster does suggest that a musty smell, soft spots when you walk or floors that bubble up likely require subfloor replacement as well. If you're not comfortable with doing all of these tasks, you should defer to a professional.

Since you'll be walking on your new floor, it needs to be structurally sound. Careful, precise measurements are essential when replacing the floor, subfloor and floor joists. Safe use of power tools, such as saws and drills, is also important.


When working with power tools, always wear hearing and eye protection. If you'll be using chemicals of any kind, including grout, primer, paint or mortar, you should also ensure the bathroom you're working in is well-ventilated.

If you're going to be producing sawdust or tile dust while working, or if you're pulling up moldy or mildewed flooring, use a respirator. If there's any question as to whether the floor tiles might contain asbestos, consult a professional before doing anything.

Removing a Rotting Floor

The first step in replacing a rotting floor is removing the old one. Before you get started, though, be sure to turn off the water to the bathroom. If possible, you should also turn off power to the bathroom circuit breaker to protect yourself from the risk of electric shock.


Use a claw hammer or crowbar to pry up old tiles, hardwood or engineered wood pieces or laminate. Depending on the material you're removing, you may need a carpet cutter or scoring tool for removal. You'll also need to pull up the subfloor since it's most likely damaged as well. You may or may not be removing your sink, toilet, tub or shower — if you are, now is the time to demolish and remove them too.

Once the floor is removed, inspect the floor joists beneath. If they're moldy, mildewed or have water damage, you may need to replace them as well. This is a specialized task best suited to a professional.


Replacing a Rotting Floor

Assuming your floor joists are intact, you can begin to replace the rotten floor as soon as you have cleaned up the debris from your demolition. Be sure there isn't lingering dust or floor pieces and thoroughly vacuum the area.

Depending on the type of flooring you plan to install, you might need a specific sort of subfloor. Laminate, engineered hardwood and vinyl usually need underlayment. If your bathroom has a concrete subfloor, you should use specific types of underlayment designed for that surface.


Consider your choice of flooring carefully since bathrooms are usually high-traffic, moist environments. Something easy to clean and maintain, like luxury vinyl tile, is a good choice. Traditional tile is also a versatile and waterproof option.