White Mold Identification and Treatment

If mold growth is visible on every wall, you’re likely dealing with a humidity based problem.  This occurs when a home has insufficient ventilation.  If the home has poorly insulated walls, the problem will be more severe.  Due to the severity of the mold growth, I recommend calling a local professional (but watch out for opportunist who overcharge).  In the meantime, I recommend improving your ventilation by running your bathroom exhaust fan 24/7 and cracking a window if possible.  This will reduce condensation throughout the home.  If the bathroom does not have an exhaust fan, install a Panasonic WhisperGreen fan.

If the problem is fairly mild, painting the concrete will reduce or greatly slow down the return of the issue.  However, if the problem is substantial, the vapor movement will cause the paint to bubble and peel.  Make sure you use clean and prep the wall and use a paint specially formulated for concrete.  Specialty coatings designed to stop vapor movement do exist, but they typically work best on new concrete.

It’s always best to begin with an investigation of the moisture source.  For example, check the downspouts above to ensure the water is directed away from the concrete wall.

Yes, bleach can effectively kill/disable mold on hard surfaces.  See this study.  However, bleach has several negative characteristics (stains materials, unhealthy for humans, etc.)  Therefore, mold remediation professionals often use alternative chemicals such as quaternary ammonium compounds.  Organic, plant based chemicals such as Benefect are effective as well.

It’s critical you first identify the cause of the mold.  Without addressing the underlying moisture source, the mold growth will return.  No chemical can prevent mold growth if elevated moisture is present.  In time, the mold will simply grow on top of the new dust that settles on top of the cleaner/coating.

Assuming the area of mold growth is fairly small, the mold growth can be scrubbed off with a detergent/water solution.   More powerful chemicals, such as bleach or quaternary ammomium compounds are necessary to kill the mold.  However, because you’re physically removing the mold by scrubbing and wiping, the killing power of the cleaner is not necessary.  White mold growth can typically be removed without leaving lingering staining.  If staining is visible after scrubbing, you’ll have to sand and refinish the material to address the discoloration.

Yes, if you thoroughly remove the mold spores, there should be no danger in bringing the items into your home.  After cleaning, you might see residual staining on the items.  Staining is much more likely to occur with black mold vs. white mold.  This is not active growth and poses no health threat.

If the items are non-porous, such as wood, plastic, etc. the cleaning should be fairly straightforward.  Heavy scrubbing is not needed.  Simply damp wipe the items with a cleaning agent.  If the items are soft/porous, such as upholstered furniture, removing all the spores can be difficult.  I would recommend a professional for the soft/porous items.

There are two questions you need answered:  1. Is the mold growth currently affecting the air quality?   2. What is causing the mold growth?

If the mold growth is systemic, I recommend hiring a local company to inspect the home and collect an indoor air quality sample.  1-2 samples (non-viable) should be sufficient to determine the severity of the issue.  Make sure they also evaluate the cause of the mold (i.e. high humidity, moisture intrusion, etc.)  It’s critical you determine the cause of the excess moisture that is ultimately creating the mold growth.

In the interim, keep a few windows cracked open and run the bathroom exhaust fans 24/7.  This will provide a constant influx of fresh air and lower the mold spore count while you investigate.  If you have asthma or are experiencing other serious symptoms, contact your doctor immediately.

The first step is to identify the moisture source.  There are 3 possibilities.   1.) Vapor emissions from the concrete slab.  This occurs when water vapor travels upward through the slab.  It’s most common in older homes with missing vapor barriers.  This can cause excess both moisture in the carpet and increased humidity in the air.  The increased humidity can lead to mold growth on contents such as a sofa.  2.) Liquid water intrusions can have the same affect, but these are typically obvious (i.e. carpet is wet to the touch).

3.)  The second possible cause is excess humidity due to poor ventilation and insufficient heat.  Basements without adequate air flow and heat are prone to high humidity.  Over time, this high humidity creates an environment conducive to mold growth.

Action steps:  Purchase a relative humidity gauge and monitor the RH.  Pull back the carpet in a corner and look for signs of water intrusion on the concrete and the carpet pad.

Great question.  Short answer = No, white mold will not cause rot.

Long Answer.  Rot is caused by wood decay fungi.  These are not considered molds and typically require much higher moisture levels to flourish.  They also require much more time to grow.  While mold can grow in a matter of days, wood decay typically requires months of saturation.

The prevention strategy is the same for both – get rid of the excess moisture.

While there are many thousands of types of mold, only a few types of fungi cause wood rot.  If you observe white mold growing on your subfloor, that mold will not turn into wood decay fungi over time.

Based on the photo, it certainly looks like white mold growth.  If you need definitive proof, I recommend a tape lift sample kit.

You’re on the right track. Drilling holes will allow the shoes to breathe (as long as you don’t put them away wet). You’ll also need to ensure the closet does not have excess humidity. Make sure there is at least a 1/2″ air gap between the bottom of the door and floor/carpet. If it’s an older home with poorly insulated walls, you might need to keep the door cracked slightly to allow heat to enter the closet. If humidity still remains a concern, consider placing a Damp Rid unit such as this or this.

It’s difficult to fully confirm from the photo. Does it have a fuzzy appearance? Does it wipe off with damp paper towel? If yes, it’s likely mold. If it is crusty or difficult to wipe, it is not mold. I recommend a tape lift style test to confirm whether it is mold.  If the test is positive, hire a local inspector to identify the source of the moisture. Systemic mold growth like this is usually due to humidity. Buy an RH gauge and try to maintain <50% throughout the home.

Yes, this looks like mold growth.  Especially considering there is plumbing on the other side of the sheetrock. We can rule out condensation, because it’s an interior wall.  I recommend checking the wall with a moisture meter.  If it’s above 20% M/C you likely have a leak.  Next, you’ll need to determine if it’s due to a supply line, drain line or shower surround failure.

Yes, that is very likely mold growth.  The amount shown in the photo is fairly minimal and would not cause structural degradation. If the mold growth is systemic throughout large portions of the attic, it’s likely due to an ongoing condensation issue.  If it’s only in a limited area, it might be due to the original construction or a past, one time incident (mold doesn’t fade with time).

If the mold growth is systemic, I recommend evaluating the ventilation (ridge and soffit).  Also, check for disconnected bath fan ducts and a lack of air sealing on the ceiling.

This looks like blown-in fiberglass insulation (efflorescence would dissolve with water and mold wouldn’t have this kind of structure).  It’s pretty unusual to see insulation forced through a vented brick.  Was the wall recently retrofitted with insulation?  If so, the process might have forced insulation through the holes.

This is a bit strange. It certainly looks like distortion caused by a water intrusion. Condensation would not occur on an interior wall. Therefore the water must be coming from a liquid source (roof/ plumbing leak, etc.) I recommend renting or borrowing a moisture meter to verify the presence of water and trace the pathway to the source. If there is a bathroom above this area, check around the toilet and shower with a moisture meter. If it’s the top floor, check the attic for a roof leak.

Rising damp (capillary action) will only occur if this wall sits on a concrete slab. If there is a crawl space below this floor, you’re not dealing with capillary action. You’ll need a moisture meter to verify the moisture source. These can often be rented at local construction rental shops. If it’s dry, the mold is likely due to damp materials during the original construction of the wall. Because it’s an interior wall, condensation is unlikely unless the interior RH is extremely high. If it’s wet (and there’s truly no plumbing in the wall), you might have a roof leak. Though rare, I’ve certainly observed roof leaks traveling down walls without leaving obvious damage on the ceiling.

Assuming the shoes are stored in a closet, it is likely mold growth. White mold growth on shoes is nearly always due to high humidity. Closets in an older home often suffer from elevated humidity due to the lack of air flow and heat, combined with poorly insulated exterior walls. Keeping the closet door slightly open is often enough to solve the issue. This will allow heat to enter the area and moisture to escape. You can also assist the dry out by installing a moisture absorbing material such as Damp Rid.

They can be salvaged, but it will require heavy cleaning.  First, treat them with a mildicide such as Benefect.  After this dries, vacuum any 3 dimensional growth (do this outside – as some spores will make it through the filter).  Lastly, lightly sand the wood to remove any lingering mold staining.  Wear a mask during the cleaning to minimize your exposure.

No, the color of the mold does not change.   Instead of describing it as ‘dying’ we categorize it as active vs. inactive.  When moisture is removed from the area, the mold goes dormant/inactive.  Much like a seed, it can regrow once moisture returns to the area.

This doesn’t look like mold growth.  It appears to be deformation of the mud/plaster due to excess water. I recommend investigating further with a moisture meter.  Your goal is to identify whether the water is 1.) Entering the wall from the backside (is there plumbing in this wall?) 2.)  Occurring due to splashing water during shower usage, or 3.)  Excessively wet mud/plaster was used during the install and is deteriorating as it dries out.

If it’s the latter option, the moisture meter should show lower moisture content levels with each passing day.

Mold growth on exposed soil in the crawl space is common.  This is why it’s critical to completely cover the soil with 6mil poly sheeting.  This will prevent any mold spores (and odors) from entering the home.  I also recommend air sealing any penetrations in the crawl space/subfloor.  This will greatly reduce the amount of air flowing up from the crawl space into the home.  By most estimates, 35% of the air in the main portion of your home comes directly from the crawl space.

Unfortunately, this is fairly common in new construction.  There are a couple of possible causes.  The subfloor and joists often become saturated by rain before the roof is installed.  Over the subsequent weeks, mold growth forms before the building materials can dry out.  Another common cause is exposed soil in the crawl space.  Most builders wait until the very end to install the vapor barrier.  If the soil beneath the home is damp, this can create high humidity conditions in the crawl space.  Over time this will cause mold growth on the joists.

Interesting growth profile.  It appears the mold is only growing on a specific substance adjacent to the joist.   I can’t tell what it is from the photo.

Any mildicide (such as a quanterary ammomium compound or Benefect) will kill the mold.  In order to prevent regrowth, you’ll need to eliminate the moisture source.  Something is causing excess moisture in this specific area.

It also appears you have black mold growing on the bottom and side of the floor joist.  If this is systemic throughout the crawl space, it likely indicates excess humidity/poor ventilation.

This looks like moisture from a water leak (as opposed to a humidity based issue).  I would insist your landlord hire an inspector to investigate the issue.  A moisture meter will determine conclusively if it’s from a leak.  The amount of mold growth at this time looks minimal, but it will likely worsen with time.  Note – the mold growth will be worse on the backside of the sheet rock.

Yes, it is possible to eliminate the mold growth.  As you pointed out, the difficulty is in reaching the crevices.  There are two primary cleaning techniques you can employ – HEPA vacuuming and damp wiping.  The vacuuming is good for removing 3-dimensional growth from rough surfaces.  Damp wiping with a mildicide is best done with a mildicide such as Benefect.

Thankfully, because you’re dealing with a solid surface, you can readily judge the success of your cleaning.  If you’ve thoroughly wiped the area and you don’t see any surface growth, you’re done.  This is more difficult to determine with fully porous surfaces such as upholstered furniture or carpeting.  With wood, it’s straightforward.

Regarding worries about future growth, the mold won’t return unless the wood encounters excess moisture again.

This is likely due to poor ventilation and inadequate insulation.   This leads to a cold spot in the corner of the wardrobe which causes condensation.  Over time this creates an environment conducive to mold growth.  If possible, improve the insulation in this area.  If not, create better air flow by removing contents and keeping a 3-4″ air gap between your items and the exterior wall.  Improve your general ventilation in the home can help quite a bit (such as replacing your bathroom exhaust fan with a constant flow unit).

This is a tricky one.  It looks somewhat like mold growth, but the pattern is unusual.  I would collect a tape lift sample of the white substance and drop it off at a local lab.   Also, purchase a relative humidity gauge to check the RH in the storage unit.  It should stay below 55%.

In the vast majority of cases, this type of mold growth is due to excess humidity.  While the cedar will help prevent mold growth on the walls, it won’t do anything to prevent growth on your clothes, shoes, etc.  The Damp Rid style packets can help, but you’ll likely need to take more extensive measures.  First, you’ll need to monitor the humidity. Purchase an inexpensive relative humidity monitor and place it in the closet.  Your goal is to keep it below 55%.   You might need a dehumidifier to keep it under this number.

Once this is achieved, cleaning chemicals will not be necessary. If you need to clean up past mold, using something like Benefect.

You’ll also want to verify whether you have vapor emissions or other water intrusion issues.  Contact a basement drainage / waterproofing contractor and have them inspect the area.

This level of mold growth is likely due to a water intrusion (as opposed to humidity).  The best way to definitively verify a leak is with a moisture meter.  Wait until you experience a significant rain event to ensure you identify any leaks.  Scan the area with a pinless moisture meter.  These can often be obtained from a local contractor rental business.

If all else fails, cut a small hole in the sheet rock.  If there’s mold on the backside of the sheet rock, you have a liquid water intrusion.  If it’s only the room side of the wall, it’s a condensation issue. This will also give you the opportunity to evaluate the insulation level within the wall.

This sounds like it’s a humidity based issue.  I recommend purchasing a relative humidity gauge and mounting it in the closet.  If it’s consistently above 70%, this is likely the cause of the mold.

Closets often suffer from poor air movement, which leads to elevated humidity.  Keep the closet doors open a bit to allow airflow.  If this isn’t possible, considering replacing the doors with a louvered model.  Also, make sure there is sufficient space between the contents to allow for air circulation.

Your winter heat level is sufficient (68F).  Increase your ventilation to the home whenever the outside air is cooler than 68F.  The easiest way to do this is by running your bathroom exhaust fan continuously or on a programmable timer (i.e. the AirCycler SmartExhaust).

During the summer the only way to reduce the humidity is through your air conditioner/dehumidification.  If you’re continuing to see mold problems in the summer, despite opening the closet doors, I recommend hiring an HVAC company to evaluate or replace your air conditioner.

Based on your description, this is very likely a humidity problem.  Whenever you see mold growth in multiple places (i.e windows, bedding, furniture) it’s almost assuredly a humidity issue.  I recommend buying a relative humidity gauge.  See the guidance in the previous entry above.

The mold growth on the carpet requires a bit more investigation.  Is the carpet on a concrete slab?  Is so, you need to verify if you’re dealing with vapor emissions through the concrete.  This is very common.  There is some good info on our basement mold page that should point you in the right direction.

It’s possible the mold growth on the carpet is from the humidity.  This typically only occurs in homes with very high humidity.

Regarding the cleaning, it is certainly worthwhile, but it will only postpone the issue.  The only way to fully stop the mold growth is to solve the moisture problem

I moved your question and answer over to the mold humidity page.

This is due to elevated humidity in the basement.  Typically this occurs due to a lack of heat during the winter months.  The lower temperature leads to increased humidity, which in turn causes the mold growth.

The easiest solution is to simply increase the temperature of the basement.  Also, install a relative humidity gauge in a central location.  Your goal is to keep the RH under 50% during the winter months.

In addition to increasing the temperature, you might need to actively ventilate the basement.  Running an existing bathroom exhaust fan can achieve this.  If no bathroom fan exists, you can install a wall mounted exhaust fan.

This looks like white mold growth.  If the room is on a concrete slab, I recommend investigating the area for vapor emissions.  If not, the problem is likely related to elevated humidity throughout the house.  Depending on your climate, this can be dealt with either by increasing your ventilation or installing a dehumidifier.  If the problem occurs during the winter months, increase ventilation.  If it occurs in the summer, use a dehumidifier.

This is a weird one.  The flaking off and floating in the air does not sound like mold growth.  This is one of those very rare cases where I would recommend testing the substance.  It’s possible it is due to boiling large quantities of starchy foods such as potatoes, noodles, etc.   Consider upgrading your range hood to a higher CFM model to ensure all vapors are exhausted during cooking/boiling.

I wouldn’t worry about identifying the specific type of mold growth.  The remediation and prevention is the same, regardless of species.  Your need to lower the humidity in the area these tapes are stored.  Aim for a relative humidity of <50% with<60% as your maximum.  If you live in a climate with cool winters, this can be achieved by increasing the ventilation to the storage area and increasing the heat/temperature.  The higher the temp, the lower the RH.  Purchase a relative humidity gauge to monitor your efforts.  If you live in a very humid location such as Florida, you’ll need active dehumidification.

Humidity problems are typically worse in closets or cabinets, due to the poor air flow. Try moving the tapes to an area that is more actively conditioned/heated.

Mold growth on clothes and furniture is due to excessively high humidity.  In a warm/humid climate such as the Southwest US, this occurs when the air conditioning is not adequately stripping the humidity from the air.  In wet/cool climates such as the Pacific NW, this occurs in poorly heated rooms or closets with inadequate ventilation.  The answer depends on your climate. If this is occurring during the winter months and you live in a cool climate, increase your heat and ventilation.  The easiest way to improve ventilation is by simply running your closest bathroom exhaust fan 24×7.

If you live in a warm/humid climate, contact a HVAC company to investigate the issue.

In both scenarios, your goal is to keep the relative humidity (RH) below 60%, ideally below 55%.  You can purchase an inexpensive RH gauge for ~$30 from a hardware store or online.

These types of test kits (petri style) are highly inaccurate.  The substrate in the dish is designed as  perfect food source for mold growth.  Even the cleanest home will contain enough mold spores to cause growth on those kits.

I do not recommend replacing the drywall.  The drywall acts as a containment barrier.   If mold growth had occurred in the past, it is completely sealed and having no impact on the indoor air quality.   Additionally, unless you’re experiencing an ongoing water leak in the all, the mold growth is dead/dormant.  It cannot grow without moisture.

Yes, I recommend remove the contents from the moldy boxes before moving anything to your home.   I would perform the operation outside.  Arrange a cleaning station to take the contents from the moldy boxes, wipe the items, then place them into clean boxes/bins.

If the contents are non-porous (i.e. ceramic, metal, etc.) they can be easily cleaned with a damp wipe.  If the pieces are semi-porous, such as wood, they can be cleaned, but it may damaged the finish.  Porous items are difficult to clean.

I posted the answer to your question on the attic mold page.

It appears the room is suffering from very high levels of humidity. This is due to either a hidden water leak, or more likely, poor ventilation.  Often cases this severe are due to a combination of the two.  Your focus should be on finding the source of the excessive moisture (whether airborne or liquid) instead of cleaning.  The mold and fungal rot will continue to return until the moisture is removed.

If the room is above a crawlspace, investigate the area for standing water or a missing vapor barrier.  These issues can often lead to high levels of humidity in the rooms above.  If the room sites on a concrete slab, test the slab for vapor emissions.  Concrete can allow a surprising amount of water vapor to pass through it, leading to elevated humidity.

If none of these yield fruit, your next focus is on indoor humidity.  Purchase a humidity gauge and mount it on the wall in the room.  If it rises above 55% during the winter months, you need to increase ventilation. Increasing the heat/temperature of the room will also lower the humidity.