How To Tell If Water Damaged Subfloor Is Okay: A Quick Guide

Knowing how to tell if water damaged subfloor is okay can save you the trouble of unnecessary and expensive repair costs. You would need to look for telltale signs that the damage on your subfloor is severe and that it would need replacing.

Subfloors, concrete and wood alike, are highly prone to water damage. The key to fixing it with ease is to detect the signs of wear early to prevent it from worsening and spreading. Continue reading to know if your subfloors are okay and everything else you need to know so you can effectively assess the damage on your own.

how to tell if water damaged subfloor is okay


How To Know If Your Water Damaged Subfloor Is Okay


Step #1. Listen for a loud squeaking on your floorboards

It is not uncommon for a floor to have a little bit of squeaking. Often, people would overlook the annoying noise and just avoid walking over the creaky part of the floorboards. However, loud and distinguishable squeaking could mean that the material of your subfloor has become warped or twisted.

When nails that connect the subfloor to the wooden joists move in and out repeatedly, it produces a squeaking noise. Ideally, you should nail down the subfloor firmly to the joists. In cases of potential water damage, the nails work themselves loose, and the infamous squeaks arise.

You should check underneath the floorboard if you hear any loud creaking to assess the damage. From there, you can start planning the repair process.


Step #2. Check for signs of mold

If a strange or musty odor is coming from your floor, the smell is likely from a moldy contaminated subfloor. Mold from water damage can cause your floor to become soft, uneven, and even squeak.

You may find it challenging to find the source of the unpleasant smell when dealing with a molding subfloor. While doing so, you should wear a mask or use some other respiratory protection as breathing in the spores from mold can put your health at risk.

There are various methods you can try to remove the mold from your subfloor by yourself. The downside is that it carries the risk of spreading the spores around, which could endanger you and those around you. It would be best to call for professionals to remove it instead.


Step #3. Look for cracks on tiles

Cracks on tiles can signify that the subfloor beneath it has become weak and flexible. Tiles need a robust and rigid surface underneath to prevent them from breaking and cracking. If your subfloor isn’t firm enough to hold up the tiles, you can confirm this by scrutinizing your tiled floor for signs of breakage.

You can also check the back of the loose tiles to see whether or not the problem is with the subfloor and not the cement board or anything else. If the other side of the tile is completely covered with dried thinset, then you can be sure that you’re dealing with a subfloor problem.


Step #4. Look for uneven or sunken sections

If you feel the floor shifting and sinking while you’re strolling through your home, you can be sure that it is a subfloor issue. When the floor sinks around, and between floor joists, it’s a telltale sign of damage.

A combination of deteriorating wood and constant foot traffic causes this issue. Although water damage is still suspect, sinking floors could also be caused by improper subfloor installation. Wooden subfloors usually deteriorate because of moisture issues, and managing moisture is the most effective way you can prevent issues like these from taking place.


Step #5. Inspect the finish floor for damage

The easiest way to see if your subfloor is worn out is to inspect the finish flooring itself for any signs of outward damage. Although a breakage may look like a simple flooring issue, it may actually mean that your subfloor needs replacement.

Cracking tiles, warped wood, or peeling Linoleum floor finishes can indicate a deeper problem that needs to be resolved. Careful inspection may reveal that the problem is actually a subfloor issue.

A cupping hardwood floor could be a sign that water may be warping the material underneath. Cracking tiles may mean that the subfloor isn’t providing enough support. A Linoleum Floor that is bubbling up could be caused by moisture that was built up under the flooring.

If you think that your subfloors are damaged extensively, it would be best to call your insurance provider or your lawyer. In doing so, you can figure out if you can get compensated for repairs from your insurance coverage.



You don’t always need to replace a water damaged subfloor. In most cases, if dealt with early, you can effortlessly dry and repair the wet area using the right tools and proper know-how. However, if you ignore a wet subfloor for too long, you risk irreversibly damaging it due to rot, mold, and other contaminants.

Knowing how to tell if water damaged subfloor is okay can help you decide whether or not you should replace your subflooring. By simply noticing the signs of damage early, you can salvage your subfloor and save yourself the trouble of having to replace it entirely.

1 thought on “How To Tell If Water Damaged Subfloor Is Okay: A Quick Guide”

  1. Thank you so much forbposting thus lifesaving information I literally thought I was going insane everyone whom I told to look and feel for themselves about my floor rising and sinking I was thinking it was treeroots perhaps at first being logical in explanation but then the rapidly consistent movement underneath as if it was a big snake I thought I was losing my mind for months think a huge snake lived underneath my apartment or in my carpet then with no logical explanation then maybe I thought my house was haunted seeing my floors move w/furniture swaying slowly rising up as it had sinked in to the ground but you have no idea Thank you so very much for giving me sainity everything you described fits my rotten musty mystery smell in my home my bubbling kitchen floor to my bedroom feeling like I’m on some acid trip all logically explained in everything that’s been going on with my apartment… so bless you kindly for posting this life saving info of key knowledge now I just hope my building doesn’t collapse which could that happen from extremely rotten molding subflooring and walls as well ? Either way this is potential LIFE THREATENING & HEALTH RISK at the rapid rate this is progressing & sad thing is nobody would believe me well now I can explain this matter more sufficient but truth in logic THANK YOU THANK YOU

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