The short answer
Visual Signs
Start by scanning the floor surface for any discoloration, dark stains, or a change in texture. Water often leaves a watermark or causes the finish to bubble or peel. Look closely at seams between planks or tiles, as water can seep into these gaps and cause swelling or lifting.
Check the baseboards and the lower parts of walls near the floor. Water that has been sitting can cause paint to blister or wallpaper to peel. Also, look for any buckling or cupping in wood floors, and for tiles that feel loose or have cracked grout. These are all clues that moisture is present.
If the floor is carpeted, feel for dampness and look for stains that spread or darken over time. Pay attention to areas near doors, windows, and exterior walls, where condensation can collect. A musty odor near the floor is another strong indicator of hidden moisture.
- Dark spots or streaks on the floor
- Warped, buckled, or cupped planks
- Loose or cracked tiles
- Peeling or bubbling finish
- Musty or earthy smell near the floor
Touch and Feel
Walk barefoot or in thin socks across the floor, especially in areas that look suspicious. A damp spot will feel cooler than the surrounding dry floor. Press down with your hand or foot to see if the floor has any give, which can indicate water damage underneath.
Run your hand along the surface and edges of the flooring. Water can make the material feel rough, swollen, or spongy. For hard floors, place a straight edge on the surface to see if it rocks or has a hump. Any unevenness can be a sign of moisture swelling the subfloor.
In rooms with a concrete slab, feel for cold spots near baseboards or around plumbing fixtures. Condensation from a leak in the slab can make the floor feel cool even if the surface looks dry. Trust your senses; if it feels damp, it likely is.
- Cooler spots on the floor
- Spongy or soft areas when pressed
- Rough or swollen texture
- Uneven surface or humps
- Dampness at the edges of the room
Using a Moisture Meter
A moisture meter is a simple tool that can detect water hidden inside the floor. You can buy one at a hardware store or rent one. Press the pins or the sensor plate against the floor surface. The meter will give a reading of the moisture level, and a high reading means water is present.
Use the meter in several spots, including areas that look fine, to compare readings. Follow the manufacturer's instructions for the type of floor you have. For wood floors, the meter can measure the moisture content of the wood. For concrete or tile, use a non-invasive meter that reads through the surface.
- Measure in multiple locations for comparison
- Use the correct meter for your floor type
- A high reading indicates hidden water
- Check around plumbing and appliances
- Repeat readings after a few days to see if moisture spreads
Checking Common Sources
Water in the floor often comes from a leak nearby. Check under sinks, around the toilet, and behind the washing machine or dishwasher. Look for dripping pipes, loose connections, or signs of old leaks. Also, inspect the water heater and any shutoff valves for moisture.
For a slab foundation, a leak in the pipes under the concrete can wick water upward into the floor. If you notice a damp spot in the middle of a room with no obvious source, the leak might be below. Turn off the water supply to the house at the main valve to see if the dampness stops, which can confirm a leak.
- Under sinks and around faucets
- Behind the toilet
- Around the washing machine or dishwasher
- Near the water heater
- At the base of exterior walls
When to Call the Pros
If you detect water but cannot find the source, or if the damage looks extensive, it is time to involve local water damage pros. They have specialized tools to trace moisture and can inspect behind walls and under floors. Acting quickly can help limit the damage to your floor and subfloor.
The pros can also perform a water damage inspection to identify all affected areas. If the flooring is badly damaged, they may need to remove and replace it. For wood floors, they might attempt restoration. The right approach depends on the type of floor and how long the water has been present.
Before starting any work, check your insurance policy to see if water damage is covered. Policies vary, and your insurer decides what is covered.
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Call Now (214) 730-5993Frequently asked questions
What does water damage under a floor look like?
Look for dark stains, warping, or a musty smell. The floor may feel spongy or have a hump. In severe cases, tiles crack or wood planks separate. If you see these signs, there is likely water underneath.
Can I detect water in a concrete floor?
Yes. Use a non-invasive moisture meter designed for concrete. Also, look for white or gray mineral deposits on the surface, which can indicate moisture wicking up. A plastic sheet test can also reveal rising moisture.
How fast should I act after detecting water?
You should act quickly. The longer water sits, the more damage it can cause, including mold growth. Turn off the water supply if you can, and contact the pros for an inspection as soon as possible.