How To Fix Water Damaged Subfloor Under Stone Tile: 4 Steps

Water damage repairs include exposing, cleaning, and treating the affected area. Here’s a guide on how to fix water damaged subfloor under stone tile.


how to fix water damaged subfloor under stone tile

How do you spot a water damaged subfloor under stone tiles?

Most of the time, water damage in subfloors goes unnoticed. The water damage eventually becomes too widespread. Since water and moisture cause water damage, your subfloors and tiles might be affected.

If you notice that your tiles are loose or there’s a musty smell coming from the floors, then there’s probably water damage going on. Spots, stains, and molds are also signs of water damage.

It’s always best to look for these signs regularly. This way, you’ll immediately know if your home needs water damage repairs.


How Do You Repair Water Damaged Subfloor Under Stone Tile?

Now that you’ve discovered water damage on the subfloor under your stone tile, what do you do? Keep reading this article to learn how to fix water damage on subfloors.


Step #1. Assess the situation

After removing the stone tiles to expose the subfloor, the first thing you’ll need to do is to inspect the subfloor. Watch out for any discoloration, spots, stains, musty odors, and rotten areas.

If there’s a minimal amount of water damage, then you can opt to repair it on your own. However, if the water damage spans a large surface, then you might want to consider calling a professional water damage repair service.


Step #2. Prepare the materials

If you decide to repair the water damage on your own, you’ll need to prepare a few materials for the project:

  • Chalk
  • Protective gear
  • Pry Bar
  • Trash Bag
  • Heavy-duty vacuum
  • Dehumidifier
  • Circular saw
  • Screws


Step #3. Make the appropriate repairs

To begin, mark the water damaged area with chalk. Make sure to draw a little bigger than the affected area.

Keep in mind the position of the floor joists too. Mark near the posts; you’ll get a cleaner finish if you do this.

With the marks in place, it’s now time to cut out the affected area. Put on your protective gear such as work gloves, eye protection, and an industrial mask.

Using a circular saw, cut out the water damaged subflooring at a depth of one inch. Carefully follow the chalk marks you made earlier. Cut precisely as much as possible.

The previous step made the subflooring looser. With a pry bar, you can now carefully pull the subflooring material upwards. Be careful, though. If you rush this step, you might hurt yourself.

Prepare a trash bag to place all the dirt, debris, and other objects that might accumulate when you pull up the subflooring. Using a heavy-duty vacuum, get rid of the remaining dust and debris in the affected area. Don’t forget to dispose of the trash bag properly!

Now that the area’s clean, you need to wait for a while. The subflooring needs to be dry before you install a new subflooring material. It might take a few days, but you’ll need to place a dehumidifier near the affected area.

Remember, the affected area should be dry! If it’s already dry, then you can proceed to the next step.

If your floor joists have water damage, you can reinforce them by placing 2-inch by 6-inch boards on their sides. It will strengthen the floor joists.

Measure the entire affected area, then cut out a new subflooring material to the exact measurements. However, you’d need to allow an eighth of an inch gap between the old and new subflooring. The new subflooring will expand eventually, so you need to prepare for that.


Step #4. Finishing touches

With the subfloors repaired, you can now reattach your stone tiles to the subfloor. If the previous tiles are in good condition, then you can reuse them.

However, you can buy the same tiles or similar ones if your previous tiles are water damaged, too. Reattach them, following the instructions on installing tiles on the subfloor.


When should you replace a water damaged subfloor?

The tutorial above is only a guide for small-scale repairs. If the water damage on your subflooring is too significant, then you should consider calling a water damage repair professional.

Professionals have more tools and expertise to repair water damaged subfloors. They can even assess the situation for you and provide you with options for water damage repairs. Additionally, if your floors are sinking, or there’s visible rotting, then it’s time to replace your subfloors.


Is it expensive to repair a water damaged subfloor?

Repairing water damaged subflooring often depends on the size of the affected area. It can range from 25 to 30 dollars for labor and 1.50 dollars per square foot for materials.

Sometimes, homeowners’ insurance covers the costs if the water damage is accidental. Incidents like a burst pipe, flash floods, and the like are under insurance coverage.



Water damaged subflooring is quite troublesome. It would be best if you made the appropriate repairs as soon as possible. Luckily, this article can help you learn how to fix water damaged subfloor under stone tile.

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