Can mold grow under ceramic tile?

Author: Lucio Schmeler  |  Last update: Tuesday, July 29, 2025

Water that gets under your tile can lead to all sorts of problems, including mold growth.

How to get rid of mold under tile?

Create a paste by mixing baking soda with water, then apply this mixture directly to the moldy grout and tiles. This paste should be left for a few minutes to soften the mold, making it easier to scrub away with a stiff brush. After scrubbing, rinse the area well and dry it to prevent any moisture from lingering.

What happens if ceramic tile has moisture underneath?

Over time, excessive water exposure can weaken the grout, cause mold and mildew growth, and even result in the lifting or cracking of tiles.

Can mold under tile make you sick?

Adverse Health Effects:

Mold releases spores and mycotoxins that can trigger allergic reactions, respiratory issues, and other health problems.

How to tell if mold is growing under the floor?

One of the most apparent indicators of mold is visible damage to your flooring. Look for: Discoloration: Patches of yellow, green, or black can signal mold growth. Warping: Uneven or bulging floorboards suggest moisture buildup, a breeding ground for mold.

Pro Advice: Why does Mold Grow on Tile?

What kills mold under flooring?

Borax is highly recommended as a mold remediation product.

What does mold under tiles look like?

If you notice black, blue, green, or pink growth appearing in water-prone areas (most commonly your grout), it's a sure sign you have mold issues. Mold will also grow under tiles, weakening their hold and lifting them. Loose or uneven tile can be another sign of mold.

What are the signs that mold is making you sick?

Although symptoms can vary, the most common symptoms seen in people exposed to mold indoors include:
  • Nasal and sinus congestion.
  • Eye irritation, such as itchy, red, watery eyes.
  • Wheezing and difficulty breathing.
  • Cough.
  • Throat irritation.
  • Skin irritation, such as a rash.
  • Headache.

Can mold grow on concrete under tile?

Yes, mold can stick to concrete as long as it has food and moisture. Mold won't feed on concrete, but the dust that settles on it contains enough nutrients for growth. In dusty, moist conditions, mold has all it needs for survival.

What does subfloor mold look like?

Subfloor mold can appear as dark spots or patches beneath flooring materials like carpets, vinyl, or laminate. It often grows on plywood or OSB substrates, common since the 1950s. The presence of subfloor mold can be hinted at by a musty odor.

How to remove moisture from under tiles?

If you are doing the cleanup yourself, use a sump pump to remove water. Follow up with a wet vac, taking care to remove as much moisture as possible around baseboards and vents. For less-extensive water damage or flooding, a mop, bucket, and towels may suffice.

How to tell if subfloor is damaged under tile?

9 Common Signs of Subfloor Damage
  1. Your floor is uneven or sunken-in. ...
  2. Your floorboards squeak — loudly. ...
  3. The room smells musty. ...
  4. Your floors shift or bounce when you walk on them. ...
  5. Your toilet is rocking or loose. ...
  6. Your flooring has cracked. ...
  7. Your hardwood floor is cupping. ...
  8. Your linoleum floor is bubbling up.

How to find a leak under a tiled floor?

One of the earliest and most visible signs of a water leak under tiles is dampness or discolouration of tiles. You might notice darker patches or even mould growth on the surface. These indicators point to moisture trapped beneath the tiles, which can worsen over time if left unchecked.

How long does it take for mold to grow under tile?

Mold growths, or colonies, can start to grow on a damp surface within 24 to 48 hours. They reproduce by spores - tiny, lightweight “seeds”- that travel through the air. Molds digest organic material, eventually destroying the material they grow on, and then spread to destroy adjacent organic material.

Does homeowners insurance cover mold?

Homeowners insurance doesn't usually cover mold damage or removal unless it's the result of a covered peril. If the mold in your residence was caused by something sudden or accidental, such as a bursting pipe or some other covered incident on your policy, you may be protected.

Can black mold grow behind tile?

However, mold can fester and grow inside the tiles, grout, and behind the walls.

What kills mold under tile?

Using bleach is one of the quickest ways to treat small areas of mould on your grout, tiles or walls. You should always wear gloves and a mask when working with bleach for protection. Mix 1 part bleach to 2 parts water & transfer to a spray bottle.

Will a dehumidifier help with mold?

Mould will easily grow and spread if the right conditions are present. So, dehumidifiers don't kill mould, but they can help to prevent it from growing inside your home by reducing humidity. However, the best way to deal with it is to get rid of its source.

How to tell the difference between white mold and efflorescence?

The easiest way to differentiate between the two is via a water test. Spray a small quantity of water on the suspected substance. Efflorescence will quickly dissolve, while mold growth will remain. The mold growth will likely mat down a bit, so look carefully for lingering material.

How to tell if mold is behind walls?

How to Detect Mold in Walls
  1. Water stains.
  2. Dark rings.
  3. Discoloration.
  4. Deterioration like peeling, bubbling, or cracking of the paint or wallpaper.

How long does it take for mold to affect you?

The time it takes for mold exposure to affect you can vary greatly. Some people might see symptoms within 24-48 hours of exposure, while others may not experience signs for weeks or even months. Factors such as individual sensitivity and the type of mold play a significant role.

What does harmless black mold look like?

Although the name implies a uniform coloring, black mold may appear black, dark green, or dark brown. It typically grows as a cluster of round spots with a distinctly wet, slimy appearance. As stated, black mold typically appears fuzzy or furry.

Can mold grow under a ceramic tile floor?

Mold loves dark, damp environments, like the underside of your tiles. Once water gets underneath them, mold can start to grow in as little as 24 to 48 hours.

What can be mistaken for black mold?

Aureobasidium

This yeast-type fungus can be mistaken for another more sinister and dangerous mold but is far less likely to make you sick. Aureobasidium can start as a slimy pink color, but it will turn brown or black and can look like black mold.

How to get rid of mold under flooring?

Scrub the affected area with a mixture of hot water and soap. Use an appropriate mold and mildew cleaner to disinfect the area. You can also use a diluted bleach solution (mix 1 cup of bleach in 1 gallon of water). Spray this cleaning solution directly onto the moldy floor and allow it to sit for 10 to 15 minutes.

Previous article
Are mini heaters bad for you?
Next article
Does Gordon Ramsay use stainless steel pans?