Dealing With Moisture And Mold Problems In A Bathroom Remodel

Dealing With Moisture And Mold Problems In A Bathroom Remodel

It is rather a conundrum. Water is the main focus of a bathroom, but water is the leading cause of damage there. No matter how well you take care of your bathroom, over time there will be water damage. This really does not become prevalent until you begin tearing out fixtures and old shower stalls and tubs, and by then you are committed. Why do these problems occur? Mainly, it is caused by the shifting and settling of the infrastructure, allowing minute cracks to appear and water tight integrity to disappear. Grout can age and develop minute cracks, and by the time you notice them, staining or worse has occurred. Because the bathroom is typically the smallest room in the house, it is the most prone to water damage. Knowing what to look for before you start tearing out fixtures and walls will go a long way in being kind to your budget. This article focuses on water damage and mildew found in a bathroom during a remodel job, and ways to fix it before the budget gets out of control.

Inspecting For Water Damage

Before you begin, do a simple inspection of the bathroom and exposed pipes. Are there signs of moisture on the bottom of the toilet tank? Is the floor around the toilet damp or spongy? Check for any visible leaks. Move on to the shower. Take a close look at tiles, and grout around the enclosure if you have a one piece pre-fab shower stall. Check for water stains or soft areas around shower walls. Check closely under the vanity. Because this space is almost always full of supplies and other things, water might be dripping in there and you may not know it. Use a strong flashlight and inspect thoroughly.

If you have a full basement, a check under the bathroom area is in order. Here, you can view the pipes and drains, and can get a good visual idea of what kind of condition the flooring is in underneath the bath. Not only look for obvious leakage problems, but inspect for old water stains and possible damage. A leak might have been fixed, but after damage has bad been done.

If you are lucky, you will only see the inevitable water stains. If there are signs of more damage, though, the best bet is to call in an expert for a thorough inspection. A qualified inspector will check for warped or rotten boards, and run tests that the average home owner cannot. They will inspect for mold using sophisticated equipment, and advise you how to proceed.

In the worst case scenario, you may find that you have mold damage behind walls or under carpeting that is old and needs replacement. This is one reason why builders and contractors don’t advise putting carpeting in a bathroom! Dealing with mold is best left to an expert, for they know the best ways to deal with it and insure that it doesn’t come back again.

What Needs To Be Done?

Let’s look at the worst that can happen. Water damage has caused floor joists and sub flooring to weaken considerable, or interior walls have damage to studs from water leaking behind walls. What needs to be done? There are several choices here. First, you can call in a flooring contractor to repair damage. Then, contact a builder and have damage to the interior walls repaired. A plumber would then be needed to fix any leaks or problems with the plumbing. Sound like a lot of hassle? It is. A much better solution would be to call a bathroom remodeler, get an estimate from at least three sources, and proceed. The last thing you need is to wait on several different contractors to get the job done. Remodeling a bathroom is inconvenient enough as it is, so why add to the inconvenience? Anyone who has ever had to wait on a contractor will know what I mean.

One of the most important things you need to do when beginning a bathroom remodel is to contact the city clerk in the town you live in, and get all information regarding permits and building codes for your project. Depending on locale, plumbing might need to be upgraded, and wiring will also need to be dealt with according to code. Be sure to get all permits for the project. It may not happen to you, but there have been cases where people have attempted a remodel on their own and have had to tear out the work because it wasn’t either done by a licensed contractor or did not meet code. Don’t let this happen to you.

How to Clean Black Mold

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Black mold appears in damp, dark areas, and can spread quickly if not taken care of. Luckily, you can clean it with cleansing detergents, such as borax or bleach, or natural solutions, such as white vinegar or tea tree oil. Wear protective gloves and goggles when cleaning the mold, and throw out any items that are completely contaminated. In extreme cases, you may have to call a professional to evaluate and eliminate the black mold.

Mold can be a nasty surprise, but there’s a good chance you have what you need to clean it lying around your home already:

  • If you have borax, use it to remove mold from tile, glass, and wood.
  • If you have laundry detergent, make a scrub to remove mold from nonporous surfaces.
  • If you have ammonia, make a spray to remove mold on glass and tile.
  • If you have bleach, use it to clean tough mold on nonporous surfaces.
  • If you have hydrogen peroxide, use it as a nontoxic cleaner.
  • If you have tea tree oil, make a spray to use as a natural fungicide.
  • If you have vinegar, use it as a cheap and effective mold cleaner.
  • If you have baking soda, you can clean both porous and nonporous surfaces.
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How To Clean Black Spots In the Bathroom

Find out how to clean black spots in the bathroom with a few supplies and a little elbow grease.

Burdun Iliya/Shutterstock

Have you ever been taking a relaxing bath, only to look up and notice black mold growing on the ceiling? Yuck. It’s a problem no one wants to deal with, but unfortunately is a common occurrence in bathrooms—especially if your home is located in a moist climate. The good news is, you don’t have to live with that mold forever. Find out how to clean black spots in the bathroom with a few supplies and a little elbow grease.

What Causes Black Mold on a Bathroom Ceiling?

Mold on the ceiling is caused by moisture that has no where to go. Mold loves moisture. Steam from hot showers and bathtubs rises to the ceiling, and without proper ventilation it can settle there. If the moisture remains too long, mold spores begin to grow. In addition to being unsightly, mold can also cause health issues. According to the Centers for Disease Control and Prevention, mold can cause “nasal stuffiness, throat irritation, coughing or wheezing, eye irritation…or skin irritation.” And even more alarming, serious lung infections can occur in people with weak immune systems.

Is black mold deadly? Find out common mold myths.

How to Clean Mold From a Bathroom Ceiling

  1. To clean mold from the ceiling, wash the affected area with a store-bought mold cleaner, or a mixture of dish soap and water. Let the area dry.
  2. Now it’s time to get out the big guns to kill the mold—bleach. Mix one-quarter cup of bleach with one quart of water and apply the solution with a spray bottle or sponge. Remember when working with bleach to crack a window for ventilation and wear gloves and eye protection. If you prefer to not use bleach, white vinegar can also be effective. Apply straight vinegar to the area with a spray bottle and allow it to sit for an hour, then wipe the area clean and allow it to dry.

How to Clean Mold in the Shower or Bath

Cleaning mold from the shower or bath can be done with the same methods used on the ceiling.

  1. Clean the area with a household bathroom cleaner first, then use either a bleach solution or vinegar to kill the mold.
  2. To prevent mold from growing in the shower or bath again, keep the bathroom ventilated and control moisture as much as possible. Use a bathroom exhaust fan, crack a window when showering, and make sure to wipe away any leftover moisture with a squeegee.
  3. Take further measures by keeping a spray bottle full of vinegar in the bathroom, spray your bath and shower after use to prevent mold growth.

Psst! Now that you know how to clean black spots in the bathroom—prevent mold and mildew from growing back with an exhaust fan. Here’s how to clean your bathroom exhaust fan to ensure it’s running properly.

Mold in Bathroom

Bathroom Mold Removal

If mold has begun to grow in your bathroom you need to remove it immediately. You can use a sponge, cloth or scrubbing brush to clean mold off most bathroom surfaces and an old toothbrush to get into hard to reach places where mold has begun to grow.

The How to Kill Mold page describes solutions you can use to kill mold in the bathroom including:

  • Bleach
  • Borax
  • Vinegar
  • Ammonia

Once the mold has been removed, mold inhibiting solutions such as vinegar can be used to regularly clean the bathroom to prevent the mold’s return.

If mold is growing in sealer and you cannot get rid of the mold then the sealer may need to be removed and replaced. Walls which you cannot seem to remove the mold from may also need to be cut out and replaced as a last resort.

A complete guide to removing large areas of mold growth from your home is at the Mold Removal page.

Removing Mold From Tiles and Grout

Mold often grows on tiles or in the grout around them. You should be able to easly remove mold from tiles by scrubbing or wiping with a cloth. Mold growing in grout can be more difficult though. Bleach can often be useful for killing mold in grout and fading away mold stains. The grout may require a good scrubbing with a toothbrush or scrubbing brush.

Applying sealer to the grout can also be helpful. If you can’t get all the mold off grout you can remove and replace the grout. Use a flat screwdriver to scrape out the old grout and then apply the new grout mixture.

A more detailed guide to dealing with mold on tiles and grout is at the How to remove mold from drywall, wood, carpet, tiles and grout page.

Causes — Why and How Mold Grows in the Bathroom

It’s very common for mold to be found in bathrooms. One obvious reason why is that there’s lots of water and humidity in the bathroom.

Frequently running water in the bathroom basin, the bathtub and the shower creates wet surfaces and puddles of water. If you don’t dry this moisture out quickly it can easily lead to mold growth.

On top of this, when the water in the bathroom does dry out it evaporates into the air and increases the humidity. Steam from the shower or a hot bath also makes the bathroom more humid. Since bathrooms are often not well ventilated the humidity tends to hang around and wet surfaces take a long time to dry out.

For more about what causes mold in the house visit Causes of Mold.

Mold in Shower and Bathtub

Mold can often be found in the shower and the bathtub. Grime from body oils and soap scum which is washed off and onto the shower or tub create a food source for mold to feed on. And of course there are abundant water sources for mold created by the running water and steam.

To prevent mold growing in the shower or bathtub regularly clean both with a cleaning product of your choice. After cleaning, wipe the shower and tub dry to minimize left over moisture. You can also buy plastic inserts for the shower and bathtub to prevent mold growth. These inserts can be easily taken out and cleaned.

There are more ways to prevent mold in the bathroom and the home at Prevent Mold.

Mold in Bathroom Basin

Mold can frequently be found in the bathroom sink or basin for the same reasons it grows in bathtubs and showers: soap scum and grime provide a food source for mold and the running water from the tap provides a source of moisture. Again, the basin should be cleaned regularly to prevent mold beginning to grow.

Mold in Bathroom Drains

If there’s mold in your bathroom drain you might be able to remove it by scrubbing it away with a brush or cloth. Remove the grate of your drain if possible and scrub the mold growing inside the drain pipe. You might be able to unscrew the drain pipe underneath (if it’s the bathroom basin, for example) if you have trouble reaching the mold.

Pouring drain cleaner or a mold killing solution like bleach or vinegar down the drain is another thing that might kill mold inside a drain. You might not be able to kill all the mold this way though if the solution doesn’t come into contact with all of the mold for long enough.

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Mold Caused by Blocked Bathroom Drains

Drains which do not drain water properly can also contribute to mold growing in bathtubs, showers or basins. Any water that doesn’t drain properly and sits in the drain creates a moisture problem. Any environment like this where water is collected and stands for long periods can easily grow mold.

If there is a build up of water in the drain, ie. the water is not drained as fast as you can run the water from the tap, then there is a problem with your drain being clogged. You can buy chemical products from the supermarket to unclog your drain or call a plumber if the problem persists.

Mold on Objects in the Bathroom

Keeping a large numbers of items in the bathroom such as shampoo bottles, beauty products, old soaps can lead to mold growth, particularly if the bottles and items are frequently getting wet. Wet surfaces sitting on other wet surfaces such as bottles on the bathroom basin take longer to dry and can trap water.

You should make sure items in your bathroom don’t sit on surfaces which are often wet. Store the items somewhere up higher, ideally on a shelf which remains dry during showering.

Also the less items you have the less likely it is for them to cause mold growth. Minimize objects in the bathroom by using up any nearly empty shampoo bottles or other products, throwing away any empty bottles, or storing things not frequently used somewhere else. When you clean the bathroom remove all extra objects. Clean them separately before returning them to the bathroom to prevent mold growth.

Reducing Humidity in the Bathroom

Ideally the humidity in the bathroom should be kept below 55% to prevent mold growth. You can maintain this by ventilating your bathroom well, especially after you’ve had a shower or bath. Turn on the bathroom fan while you shower and leave it on for about five minutes afterwards to remove the steam and dry out the air. If you don’t have a bathroom fan, or as well as using the fan, open the window to let steam out and circulate the air.

Besides leaving the window and door of the bathroom open after having a shower or bath, if you are concerned about the moisture levels you can also wipe down wet surfaces so they dry faster.

Regular Bathroom Cleaning

Regularly cleaning the bathroom will prevent mold starting to grow. Once a month wipe down the bathroom with an anti-fungal solution. Remember to include the ceiling when you do this as it is a prime area for mold growth. The floor can be mopped with mold inhibiting solutions such as vinegar.

Another good tip is to spray the bath and shower once a month with undiluted vinegar which prevents mold and deodorizes the bathroom. You don’t need to rinse the vinegar away, instead let it dry on its own.

Drying Wet Surfaces in the Bathroom

Drying wet surfaces manually will reduce moisture sources as well as the humidity level of the bathroom since the water on these surfaces would otherwise evaporate into the air. After you have had a shower or bath wipe down the tiles, glass, mirror, walls, window or any other wet surfaces with a towel or squeegee. It’s also a good idea to minimize the number of potential wet surfaces by removing any objects from the bathroom you don’t need.

Solved! What To Do About Black Mold in the Bathroom

Discolorations in your bathroom’s tile and grout aren’t just unsightly—sometimes they’re downright dangerous. Once you determine which type of mold you’re dealing with, you can wipe it out with the appropriate plan of attack.

Q: I just went to clean our rental property after the tenant moved out, and I found black mold in the bathroom. Yuck! How do I get rid of it?

A: Yuck, is right! Black mold is gross. And depending on which variety it is, it could be dangerous. If the space has been flooded or a long-term leak only recently revealed itself, what you see might be the black mold: Stachybotrys chartarum. This highly toxic mold should only be removed by a professional.

But, more than likely, an accumulation of grossness along your bathtub or shower tile indicates the presence of a more generic bathroom mold. The only way to tell for sure is to test it—either by asking professionals to collect samples or sending some away via a do-it-yourself kit—and wait for results. Once you can confirm that it’s the latter, garden-variety bathroom mold type, you can get to work ridding it yourself.


In general, mold is a fungus that’s plentiful in the natural environment and, when conditions are right, indoors as well. Take the bathroom: Its damp, dark, and often warm interior makes mold growth a perennial problem there. Without adequate ventilation or routine towel-drying after each use, black mold can easily take up residence and thrive. Here’s how you can give it an eviction notice.

1. Remove the mold.

Use an antifungal surface cleaner (such as Clorox Antifungal, available on Amazon) and a sponge or cloth to wipe mold off of non-porous surfaces like tile and porcelain. Follow up with a scrub brush on any stubborn areas, and thoroughly rinse with water. This process should remove the mold, even if some dark coloring remains.

2. Clean up the stains.

To remove the black stains that mold leaves on non-porous surfaces like grout, mix equal parts of bleach and water in a spray bottle and spray it over the stained area, allowing it to sit for several minutes. Return and spray the area again, and use a scrub brush to scrub out any remaining discoloration. Tip: An old toothbrush aptly reaches rout’s narrow lines.

3. Eliminate mold spores.

While bleach is superb at removing dark stains caused by mold, it’s not the most effective way to eliminate mold spores. Instead, spray vinegar onto the area and allow it to dry so that the cleanser can finish off any remaining mold spores.

Black Mold in Bathroom: Cause, Dangers, and How to Get Rid of It

The bathroom is one of the most important rooms in your house that you use every day. Its function to clean and freshen your body might serve the opposite; if black mold starts to grow and develop in your bathroom.

Black mold can infect any fixtures and fittings of a bathroom.

Because this type of mold likes to grow in a dampened area, bathroom fixtures that have direct contact with water such as the floor, bathtub, and shower, have a greater risk of black mold infestation.

Table of Contents

Cause of Black Mold in Bathroom

The main reason black mold infests your bathroom is due to the humidity and plentiful supply of water. Such condition provides the perfect ground for mold development.

Water coming out from basin, bathtub, and shower will create wet surfaces that are claimed by black mold as the place for it to live in.

In addition to water supply, another cause of black mold infestation in the bathroom is related to the steam evaporation. If you like using warm or hot water in the shower, the chance of black mold growing in your bathroom increases.

The bathroom does not have well ventilation system compared to other rooms in the house. It also becomes the cause that can increase humidity from the steam and water circulation inside the bathroom.

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Dangers of Black Mold in Bathroom

Broadly known as toxic mold, black mold that has infected your bathroom can put you and your family in danger. Black mold actively produces mycotoxins, the poisonous substance of fungus.

Mycotoxins can cause many health problems, including infections and allergic symptoms.

The following symptoms are caused by mycotoxins from black mold infestation.

  1. Respiratory infections, including coughing, sneezing, and sore throat. In some serious cases, the toxin can lead to pneumonia, breathing problems, and asthma attacks.
  2. Chronic fatigue, exhaustion, headache and migraines, even mental depression and mental impairment.
  3. Blood diseases, including hemorrhage, nosebleed, and mucous membrane irritation.
  4. Damage to internal organs and the suppression of immune system.
  5. Sinus congestion such as difficulty breathing, runny nose, ear infection, sneezing, coughing, and sore throat.
  6. Allergic reactions, including red, itchy, and watery eyes, as well as hives and rashes on the skin.

More bad news is, black mold does not only put people at risk but also can be the cause of pet’s sickness. Some health problems and serious infections caused by black mold are dangers for your pet’s life.

What does Black Mold Look Like in Bathroom?

Black mold in the bathroom has the muddy and spongy appearance and can be found on the bathroom floors, walls, ceilings, or shower stalls.

Colonies of ants can also detect the presence of black mold. If you find the colony of small ants gathering in one spot of your bathroom, check the spot in case black mold has infected it.

Remove Black Mold on Bathroom Wall

If the infestation of black mold on the bathroom wall is no larger than 10 square feet, you can easily remove it by doing some simple steps below.

  1. Dissolve some detergent in hot water.
  2. After you get the solution, use it to wash the bathroom wall which has been infected by black mold. Wash it thoroughly until the mold layer is covered.
  3. Wipe the wall with a clean rag. Make sure that the wall is completely dry before you move on to the next step.
  4. Apply the fungicide as the next substance. Fungicide is useful to kill fungus and molds on the wall, and can prevent them to grow in the same place. Just like the solution of detergent and hot water, you also need to apply the fungicide thoroughly on the bathroom wall.
  5. Wait for about 10-15 minutes after fungicide has completely covered the wall. That chemical substance will remove the mold from the surface to the construction of the wall.
  6. Rinse the bathroom wall one more time and let it dry.

Please note that the above steps will only work for the small area of the infected wall that is less than 10 square feet.

If black mold infects bathroom wall in a larger area, it is better for you to call professional inspectors to remove the mold and help you get rid of this dangerous organism. They will use negative air pressure to destroy the mold.

Remove Black Mold on Bathroom Ceiling

Black mold can also be found on the bathroom ceiling, especially if the ceiling has been leaking for a long time. Removal ways of black mold on the ceiling are quite similar to those that you can do for the bathroom wall.

You can use the solution of detergent or a special chemical substance like fungicide.

When you need to remove black mold on the bathroom ceiling, it is important to find the safe place to reach the mold location.

Remove the ceiling paint using paint scrapper before you clean the ceiling with a chemical substance. Don’t forget to wear protective equipment such as a mask, safety goggles, and rubber gloves.

Remove Black Mold in Bathroom Sink Drain

Black mold can also be found in bathroom sink drain. If you notice small patches in black, dark green or gray colors in the sink drain or drain pipe, mold removal steps should be done immediately.

To remove black mold in the drain, you can scrub it using a brush or a piece of cloth. Rub all parts in the structure thoroughly, including the grate that is possible to be infected by black mold as well.

If you have difficulty in reaching small parts of the drain, you can take it apart for a while and fix it back after the cleaning is done.

To optimize your cleaning, you can use some additional mold-killing agents such as vinegar, bleach, and fungicide that can help you get rid of black mold in the bathroom drain.

Prevent Black Mold in Bathroom

Preventive ways are always needed before it is too late. You can prevent black mold from growing in your bathroom by applying anti-mold paint on the clean bathroom wall and ceiling.

In addition to retaining the bathroom moisture and keeping bathroom humidity in low level, anti-mold paint is a good way. It will hold the steam produced by showers as a primary cause of black mold infestation.

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