Most rooms in a home have a wooden subfloor. It provides structural support to the floor above it, whether it's tile, laminate, hardwood, or carpet. Since the subfloor is commonly made from wooden materials like plywood or oriented strand board, it's vulnerable to water damage. Even if the floor above it is made from a waterproof material like tile, it's possible for your floor to be damaged when water intrudes beneath the tile into the subfloor. Subfloor damage can be immediate (like from a burst pipe) or can accrue over time from a slow leak in your home's plumbing.
It's important to watch out for the signs of water damage in your subfloor since it can begin to grow mold if the water intrusion isn't stopped, and mold can be difficult and expensive to remove. To learn what to look for, here are five signs of water damage in a room's subfloor.
1. Your Flooring Is Cracked or Warped
One of the most common signs of subfloor water damage is when the floor above it starts cracking and warping. As the wooden subfloor absorbs water, it will begin to expand, and the expanding subfloor creates upward pressure on the floor above it. Flooring that's glued together (like tile or laminate) doesn't have much ability to shift, so it will begin to crack and warp due to the pressure.
2. Your Floor Squeaks
When water causes the subfloor to expand, the subfloor will also pull upward on the nails that connect it to the wooden floor joists below. When you step on flooring above the raised nail, you'll push it back downward, and this makes a squeaking noise. If your floor squeaks whenever you walk on it, it may be due to subfloor water damage.
3. Your Floor Feels Soft Underfoot
If your wooden subfloor has been exposed to water for a long time, it will begin to rot and lose structural strength. A subfloor that has started to rot will feel very soft when you walk on the floor above it. This is a sign of severe water damage — if you don't stop the source of the water intrusion and replace the subfloor, it will eventually collapse.
4. Your Flooring Smells Like Mold or Mildew
If a room has a persistent mold or mildew smell and you can't see where it's coming from, it may be coming from the subfloor. Plywood and oriented strand board are both capable of harboring mold when they become wet, and they will begin to emit a distinctive odor of moldy wood.
5. Your Plumbing Fixtures Aren't Stable
Plumbing fixtures (like toilets and free-standing sinks) are commonly fastened to the subfloor in order to keep them from moving around. If you can move them easily back and forth, it may be a sign that your subfloor has started to rot and lose its strength.
If you notice any of the signs above, call a water damage restoration company and have them inspect your subfloor for signs of water intrusion. You'll need to stop the source of the water intrusion along with repairing your subfloor. If your subfloor is in good condition, it may be possible to save it by simply drying it out. If it has started to rot and lose structural integrity, however, you'll need to replace it. Contact a water damage restoration company for more information.