Hot Environmental Topics

 Did you know that many homes built before 1978 have lead-based paint, and lead was also used in stains and varnishes? Lead from paint, chips, and dust can pose serious health hazards when ingested or inhaled. Young children are particularly vulnerable, as they put everything in their mouths and lead paint tastes sweet.

 Deteriorated lead-based paint, such as peeling, chipping, chalking, cracking, or damaged paint, is a hazard and needs immediate attention. Lead-based paint may also be a hazard when found on surfaces that children can chew or that get a lot of wear and tear, such as windows and window sills, doors and door frames, stairs, railings, banisters, and porches.

Lead-based paint is usually not a hazard if it is in good,  intact condition and if it is not on an impact or friction surface like a window  

Before renting or buying a pre-1978 home or apartment, federal law requires sellers, landlords, agents, and rental property managers to:

Disclose known information about the presence of lead-based paint or lead-based paint hazards (or state there is none)

Provide all available records and reports on lead-based paint and lead-based paint hazards (or state there are none)

Include a specific warning statement about lead-based paint

Give buyers up to 10 days to have a certified inspector or risk assessor check for lead. 

The above is known as Title X and is rarely followed, meaning executed by parties involved in a real estate transaction.  people take a  Laissez-faire  "hands off" approach.  Meaning, sure, the house may have lead in it, but we like the house.  Well, this approach is not protective of human health; knowing there is a hazard does not necessarily protect you from the hazard.

If you want your house evaluated for lead and lead hazards, you will be better able to manage the hazard and protect your family.   Knowing where a hazard is and if it presents an immediate hazard is a more practical approach, but it requires a trained professional to evaluate a property for said hazards.

 Hire a certified lead professional to get your home tested for lead in several different ways:

 A lead-based paint inspection tells you if your home has lead-based paint and where it is located. It won’t tell you whether your home currently has lead hazards or how to deal with them.  A portable x-ray fluorescence (XRF) machine is used to test surfaces, with immediate results.

You can also perform a risk assessment, which tells you if your home currently has any lead hazards from paint, dust or soil, and what actions to take to address any hazards. 

You can also do a combination inspection and risk assessment, which is typically referred to as a Lead Paint Survey, which is an abridged survey that tests likely suspect areas for lead paint, such as children's rooms, playroom, hallways, areas where lead paint may become liberated, and where an exposers pathway is present.

Confused?  Don't be -  call the lead professionals.

tells you if your home has any lead-based paint, if it has any lead hazards and where both are located 

Mold in your blood work?

Where there is water there can be mold. Mold is a by product of excess moisture.

Mold in the blood, or invasive mold infections (IMIs), occurs when fungal spores enter the body. People with weakened immune systems can get invasive mold infections (IMIs). For example if you are immunocompromised you will be more susceptible.

Specialized blood tests can detect mold DNA or antibodies (IgG/IgE) to identify mold exposure. Testing for example could find Aspergillus, a type of mold.. Most IMIs are caused by breathing in (inhaling) mold spores which are readily airborne.

Part of the life cycle of molds is the production or off gassing created by the active growth of mold. Compounds produced by mold consist of Microbial Volatile Organism Compounds (MVOCs) and mycotoxins.

If you have water damaged building materials,i you should expect some form of airborne toxin indoors. The levels will be higher and humans more suspectable to indoor expose to these toxins, simple because indoors you are recycling air where outdoors you experience a dilution factor to the toxins.

If have been tested and mold markers were found in your lab work, you need to evaluate for the presence of mold. This typically starts with a mold inspection and air sampling of your home to determine if mold is present. Expect multiple air samples all of which will be obtained in rooms you frequent, such as your bedroom, family room, kitchen, basement, etc. The findings will rule out areas for mold exposer or find the smoking gun so to speak.

It is documented that mycotoxin exposure can cause immune dysregulation, neurological disorders, cancer, and other health issues. How can you be exposed to molds toxic off gassing? Well it depends on the environment where the mold is growing.

For example let’s say you have mold testing performed and mold is found and one of the molds is Stachybotrys. This mold needs constant water to grow and its presence underscores a long term water issue. That said this spore creates satratoxin which is a trichothecene mycotoxin. Yes, its sounds bad and it is, exposure causes neurotoxicity and inflammation in the brain and induces apaptosis of the olfactory sensory neurons. Exposure can also cause fatigue, headaches, nosebleeds, pulmonary hemorrhage, chest pain, moist dermatitis, and fever.   It is also a wet sticky spore so more likly to be an irritantant when enghaled.

Let’s take a more ubiquitous spore, Cladosporium. Cladosporium when found in elevated concentrations in air samples they are a significant allergen. For asthmatics and people with respiratory diseases they are a large concern. . Cladosporium also produces microbial volatile organic compounds (MVOCs), which are neurotoxic. Exposure to humans can cause severe headaches, seizures, and sleepiness.

Aspergillus which is commonly found growing on building materials including wood and sheetrock can cause immune suppression and is carcinogenic. It is toxic to cells (cytotoxic) and is a hemolytic mycotoxin, meaning it can destroy red blood cells.

My point being is that exposure to mold is often an overlooked health hazard, although the health hazard is well documented.  Properties are bought and sold without having a professional mold inspection performed. We find mold issues in one way shape or form in approximately 70% of the sites we inspect. Some have very minor issues, some are more significant. But all issues were only found from performing a professional evaluation.

Mold Questions?

Call the experts

888-301-1050

EPA Implements New Lead Dust Standards, which Take Effect January 12, 2026.

Lead is a neurotoxin that can irreversibly harm brain development in children, lower IQ, cause behavioral problems, and lead to lifelong health effects. It also affects other organs, including the liver and kidneys.

Because Lead is so harmful, the EPA has lowered the standard to be more protective of human health.

• Dust-lead hazard standards (DLHS): Testing is required for any reportable levels of lead
• Dust-lead clearance levels (DLCL):
• The new levels are 5 µg/ft2 for floor dust
• 40 µg/ft2 for windowsill sill dust
• 100 µg/ft2 for window troughs

The rule changes the game on lead in the following ways:

Increased Lead Abatement Needs:

Lead abatement contractors must meet stricter cleanliness standards after renovation or abatement activities, requiring more thorough cleaning.

Key Definition Changes:

The rule replaces "dust-lead hazard standards" with "dust-lead reportable levels" and "dust-lead clearance levels" with "dust-lead action levels".

Real Estate Mandatory Disclosure:

If a test shows levels above the new threshold, it is considered a lead hazard, which must be disclosed to potential tenants or buyers.

The rule reduces the level is allowed when a lead-abatement contractor finishes work on a property where lead has been identified as a problem. These levels would be 5 micrograms per square foot on the floor and 40 micrograms per square foot for sills.

Pertaining to the New Jersey Lead Safe Law, dust wipe towns will have to meet the new standards. Sites that fail the visual inspection have to perform a dust wipe after the hazard is addressed and meet the new standards.

New Jersey has until January 11, 2027, to utilize the new stricter standard. Landlords subject to the law must be more vigilant in property maintenance. Many sites that passed previously have avea high probability of failure under the new standard.

As the following chart shows levels have dropped by ½ on some surfaces.

Property owners, lead-based paint professionals and government agencies may identify dust-lead hazards in residential and childcare facilities built before 1978 after learning that a child living there has a high blood lead level, or because of requirements for housing receiving federal funding, among other reasons. If lead abatement is needed, EPA’s

Lead Background

Although the federal government banned lead-based paint for residential use in 1978, it is estimated that 31 million pre-1978 houses still contain lead-based paint, and 3.8 million of them have one or more children under the age of six living there. Lead-contaminated dust is one of the most common causes of elevated blood lead levels in children, and even low levels of exposure can be harmful. Lead dust commonly results when lead-based paint deteriorates or is disturbed. Due to normal behaviors such as crawling and hand-to-mouth activities, young children are particularly at risk of higher exposure to ingesting this lead-containing dust.

Historically, EPA set the same standard for the level of lead found in dust from old paint that has to be reported and the amount of lead that can remain in dust on floors, windowsills and window troughs after a lead paint abatement occurs. This action decouples the two levels, which were last updated in 2019 and 2021, respectively. This is being done in accordance with a May 2021 Ninth Circuit Court of Appeals opinion, which explains that dust-lead reportable levels (previously called dust-lead hazard standards) must be based solely on health factors, while the dust-lead action levels (previously called dust-lead clearance levels) must consider the additional factors of safety, effectiveness and reliability. Today’s rule aligns both standards with the best available science, further strengthening EPA’s efforts to protect children from lead hazards.

Environmental property inspections started with Superfund. The first standardized Phase I Environmental Site Assessment (ESA) was published by the American Society for Testing and Materials (ASTM) in 1993 as ASTM E1527-93. While informal environmental audits emerged in the 1980s following the 1980 CERCLA/Superfund legislation, the industry-standardized practice was formally developed to meet "all appropriate inquiries" requirements desired by lenders.

In theory, commercial properties bought and sold since the 1990’s would have had a Phase I or Phase II completed. Since Phase I has a shelf life of 180 days or 6 months, many properties would have had a few environmental inspections under their belt. Following this logic, as long as the operation of the property did not have an environmental impact to the property, subsequent inspections should not encounter issues.

Unfortunately, what I wrote is wishful thinking; environmental evaluations have gotten better over the years, and it is fairly common to find that older reports missed things. 1030 exchanges often circumvented environmental due diligence and old school purchases (read we did no environmental) side-stepped a Phase II ESA and therefore missed any Phase II testing. Curren Environmental is coming across an endless stream of properties that have never had environmental inspections performed, due to negligence. These sellers are taken back by buyers who want environmental inspection and associated testing. The rub is in today’s environment, lenders and buyers require environmental inspections, and anything that is found is the responsibility of the seller, even if historic contamination is found that was caused by a long-gone owner/operator of the site.

Environmental regulations are unfair and place environmental cleanup on the owner of the property, not the one who caused the contamination. Of the sites we come across with contamination, the owners who step up and address their obligation, however unfair, get their properties sold faster. The owners who bury their head in the sand, drag out transactions, and buyers walk away.

Bottom line, if the property you are selling doesn’t have a recent Phase I or has never had recommended Phase II testing, you would be best served to get ahead of things and complete an environmental evaluation. The huge advantage of this approach is that you will sell the property faster. You can also price the property sale, taking into account the money you spent on environmental evaluation and cleanup. You can’t do that after a property goes under contract.

If you have real estate-related environmental questions, Curren can provide answers and guidance.

Call the Due Diligence Experts

We get this request weekly. Someone wants to buy a house that has a buried oil tank. Sometimes the tank is being used, other times the tank is no longer in service. Let me cut to the chase, NO, you cannot accurately inspect the tank, it’s buried and is rusting, which no one can see, but you know it's true. Every buried tank will fail. When you fill up your vehicle at the gas station, those tanks have corrosion protection and very expensive monitoring and leak detection systems.

If you have a buried tank that is being used and it’s older than 20 years, remove and replace it. If you are buying the property, negotiate with the seller to remove and replace the tank and offer monies to perform this work, payable at settlement. While you may not want to open your wallet any further, you did ask about paying for an inspection of the tank, so use that money for removal and replacement.

If you have a buried tank that is not being used on a property you are buying, request that it be removed and soil sampling be completed during removal. The tank is a financial liability that someone ignored and wants to pass the problem to you.  For a matter of reference, a small tank leak can cost $10,000 to $15,0000. Removing an oil tank, maybe around $20,000.00

We just had someone call asking about inspecting an out-of-service buried tank on a property they want to buy. Turns out there is a new oil tank in the basement, which they installed to replace the perfectly functioning buried tank. Good money was wasted installing a new tank because the buried tank is fine. Excuse my sarcasm, the new tank 99% of the time was installed because the buried tank was having issues and the owner didn’t dig up the tank because they don’t want to find a problem. They would rather ignore the issue and pass it along to the next person.

Truth be told, we do test buried tanks, and we remove them in three states. But time and time again, testing is a waste of money, and the better financial approach is to remove and test the tank this 100% removing the liability of the tank in the future and is 100% accurate.

Tank Questions?

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888-303-1050

Phase I ESA Peer Reviews

What is a Phase I Peer review?

It is a professional review of the ESA report to confirm that they meet industry benchmarks for pre-acquisition due diligence.   In short, it is a peer review to see if the research that is crucial to the Phase I was properly interpreted and if there are necessary next steps to complete, aka a Phase II, which is testing. A peer review is typically done when a Phase I is brought to a transaction, and it is completed by a third party not associated with the buyer or lender.

What is a Phase I Environmental Site Assessment?

AKA ESA, or Phase I ESA, is completed to research potential environmental liabilities regarding the current and historical uses of a property as part of a commercial real estate transaction.  The report is meant to assess if current or historical property uses may have impacted the soil or groundwater beneath the property, and whether the property has an environmental liability that the owner would be responsible for. The lender is subject to the potential liability if the mortgagee defaults.

It is safe to say most commercial properties should and do undergo a Phase I ESA prior to settlement. But some transactions fall apart, and new buyers swoop in and utilize the prior buyers' Phase I. This practice is fraught with issues.   Relying on a Phase I you do not own is subject to liability. Now you can obtain a reliance letter, so you have rights to the report, but how accurate is the report? That is when a Phase I Peer Review is performed.

A Peer Review will 100% of the time be completed at a desk, but some reports are so thin and loose on quality, a site walk is also necessary.  Case in point, the photo to the left. 

This photo shows a sale involved at a heavy equipment repair facility.  The Phase I report lacked clear detail on the work area where petroleum fluids would be encountered, and,  from experience, this was too big a data gap, so a site visit was also necessary. The photo was just one of many areas where staining was evident, the concrete floor was not intact (heavy equipment weighs a lot and concrete cracks), and yes, testing was required, and remediation was necessary. 

Curren completes thousands of Phase I peer reviews every year, and the quality varies widely. Inexperienced people miss issues that should be noted and investigated. Unfortunately, some of these reviews are completed years later, and anything that was missed is well past any recourse. Not as bad as it is when the Peer review is performed before settlement, and something was indeed missed that requires further evaluation, which means several weeks of delay in settlement.

Let me discuss two real-world scenarios.   A seller gave a buyer their Phase I, which they used to purchase a property through a 1030 exchange. Years later, the property is being sold, the prior Phase I is too old to use, and a new buyer completes a Phase I and Phase II, which leads to $64,000 of environmental cleanup that was associated with prior, not current, uses. In short, in Phase I, the buyer, now seller, relied upon missed issues.

Have due diligence questions?  

I can't think of a more boring title for an environmental blog, but crawlspace oil tank removal should rank in the top 10.  As boring as it is, old metal tanks that store petroleum compounds such as diesel or heating oil are ticking time bombs, as the low sulfur content of these fuels allows interior corrosion of the tank.  Exterior humidity/moisture causes the exterior of the tank to corrode, so you have two opposing forces generating rust, and when tank integrity breaches, oil will flow.  The average cleanup cost of an oil leak in a basement is $15,000. A crawlspace oil tank leak doubles that cost simply due to the limited access to a crawlspace.

I refer to abandoned tanks as deferred maintenance because it is a project that doesn't get addressed, and when the stored oil leaks, it is now an immediate problem, with a cost much higher than if the tank had been addressed before the leak occurred.  Curren has over 30 years of experience managing tank issues and crawlspace tanks while not a favorite, are part of our overall program.  Removing a crawlspace tank is less expensive than cleaning up a leak.

Let's walk through the process, a crawlspace no matter how nice yours is it is called a crawlspace because access is limited.  The access to the crawlspace to the left is through a small hatch in the floor.

Once you get into the crawlspace, you will see a tank on the other side of the area.   The tank was likely installed after the foundation was installed but before the floor was installed, meaning the tank is wedged into the area, a great reason why no one addressed this tank 10 years ago when they converted to natural gas.  Of course, Curren got called because an oil smell was permeating the home, because the tank finally started to leak.   Fortunately, the tank was on a rough finish concrete floor, but there were still physical issues in trying to remove the tank.   As you can see, we had to cut the HEAD or end of the tank off to access the tank for cleaning, and ultimately cut the tank into 8 pieces to remove it.

If you have an out-of-use metal oil tank, call Curren  

The metal is going to rust, oil is going to leak, you will then be forced to address the tank, which is going to cost more now because you have to clean up the oil from that empty tank.

Environmental regulations are simple and unfair.  Own a property with an environmental problem and you own the problem, even if you just bought the property and didn't know or cause the environmental problem.

That is why you do a tank sweep before you purchase a property, to look for undisclosed buried oil tanks.   Only one appropriate method should be used to perform a tank sweep, and that is Ground Penetrating Radar or GPR.  GPR is used on commercial properties, so you are using a commercial technology or approach to finding tanks, which translates to a moreeffective tank sweep.   GPR, in layperson's terms, sends radar signals into the ground which will reflect off of solid objects such as pipes, tanks, etc. You get a signal like in the photo, which represents an oil tank.

A tank sweep is due diligence, an evaluation to protect a buyer of a property.  Unfortunately, people do not know what they are getting, and a metal detector is commonly misused to perform a tank sweep, with inaccurate results.  Since metal detectors can only detect metal and provide no image, the data is open to misinterpretation.

The photo shows a small pile of metal pipes, which a tank sweep said was a tank.  Curren got permits to address the alleged tank and found old sewer pipes.  Thinking that perhaps the tank sweep mismarked the tank location, we performed further evaluation with the thought that there was indeed an oil tank.  

Further evaluation found a buried object with a FLAT top, which is not a signal for an oil tank, the area was excavated, and we found an old cesspool.   This rather large object apparently was missed by the metal detector, and we determined the presumed tank was actually the buried pipes.

GPR would have found the cesspool and determined the metallic signature was buried pipes, but since GPR was not used the owner had to spend time getting permitting and digging up his yard to not find an oil tank, but now they have an old cesspool to address as cesspools are a safety issue and are a disclosure when you list a home for sale.

If you want accurate tank sweep results, use GPR

If you need a professional to complete your tank sweep, call Curren

Adding lead to paint made the paint stronger, dry faster, and moisture resistant.

Approximately three-quarters of the nation's housing built before 1978 contains lead-based paint, stain, or varnish. When properly managed and maintained, lead-containing building materials pose minimal risk. Lead-based paints were banned for residential use in 1978 due to health concerns, which means homes built after this date are unlikely to contain lead paint, stains, and varnishes on building materials.  But if you go antiquing and buy a vintage mantle, corner cabinet, and build it into your new home you may have brought lead into a post-1978 home.

Lead becomes a concern when paint, varnishes, and stains deteriorate through peeling, cracking, or chalking. As the paint, varnish, and stains break down, it create lead chips and dust. High-friction surfaces—such as windows, doors, floors, porches, stairways, and cabinets—are particularly prone to generating lead dust through normal wear and tear. While intact lead coating materials are not inherently dangerous, any activity that creates lead-contaminated dust or fumes, including sanding, scraping, or friction, can create exposure risks.

When Lead Testing is Necessary

Homes built before 1978 should be tested for lead-based paint, stains, and varnishes, particularly if you're planning any renovation, repair, or remodeling work. Testing identifies where lead is present so you can make informed decisions about how to manage it safely. If paint appears to be in good condition, knowing the location of lead-based paint helps you monitor those areas and prevents accidental disturbance during future projects.

Homes built in 1978 or later generally do not require lead testing, as lead-based paint was banned for residential use that year. However, if you have reason to believe older painted materials or components were incorporated into your newer home, testing may still be warranted.

Lead Exposure Pathways

Understanding how lead exposure occurs helps you prevent it. Lead-coated surfaces in good condition present minimal risk, but once lead-containing material separates from building surfaces through deterioration or disturbance, an exposure pathway is created. Children under six years old are most vulnerable to lead exposure because:

• They may chew on surfaces such as windowsills and door edges
• They can ingest flaking paint chips
• Their natural hand-to-mouth behaviors increase the likelihood of ingesting lead dust
• Lead can have a sweet taste, which may attract children

Lead Questions?

Call the experts 888-301-1050

Both children and adults are exposed to lead primarily through ingestion or inhalation of lead dust and fumes. Common sources include deteriorating lead paint, contaminated water and soil, certain toys and jewelry, and some imported candies or medicines. Adults face additional exposure risks through occupations and hobbies involving lead-based products, such as construction work, pottery, metalworking, or firearms handling.

Renovation and Remodeling Considerations

Renovation and demolition activities can release lead into a home's environment, which is why testing building materials in pre-1978 homes is essential before beginning any project. Federal law requires contractors performing renovation, repair, or painting projects that disturb lead-based paint in homes built before 1978 to be EPA-certified and follow specific work practices to prevent lead contamination. If you're planning a DIY project in a pre-1978 home, consider hiring a professional to test first. This allows you to either hire a lead-safe certified contractor or take appropriate precautions if you proceed yourself.

Lead Exposure Prevention

Preventing lead exposure focuses on maintaining your home and establishing good household practices:

• Ensure children cannot access peeling paint or chewable surfaces painted with lead-based paint
• Maintain all painted building materials in good condition to prevent deterioration
• Regularly wet-mop floors and horizontal surfaces, as household dust can contain lead particles
• Pay special attention to windowsills and window wells, which tend to accumulate more dust
• Keep all surfaces clean through consistent maintenance
• Wash children's hands frequently, especially before meals
• Wash toys and pacifiers regularly

Managing Lead Paint as a Homeowner

If testing reveals lead-based paint in your home, don't panic—lead paint that is intact and in good condition can be safely managed with proper maintenance and awareness.

When Lead Paint is Intact and in Good Condition:

• Regular inspection is your best tool. Check painted surfaces periodically for any signs of wear, chipping, or peeling, especially in high-traffic areas
• Maintain painted surfaces by addressing any minor damage promptly before it becomes a larger problem
• Clean regularly using wet-mopping and damp cloths to capture any dust. Avoid dry sweeping or dusting, which can spread particles into the air
• Control moisture by fixing leaks and addressing condensation, as moisture accelerates paint deterioration
• Monitor friction surfaces like windows and doors more closely, and consider applying fresh coats of non-lead paint over intact lead paint to provide an additional protective barrier (this is called "encapsulation")
• Educate your household about which surfaces contain lead paint so everyone can avoid creating dust through activities like furniture rubbing against walls

When Lead Paint Shows Signs of Deterioration:

• Address the issue promptly before it worsens. Small areas of chipping or peeling should be stabilized
• Hire a lead-safe certified contractor for any repairs or renovation work in areas with lead paint. These professionals are trained in containing dust and preventing exposure
• Never attempt to sand, scrape, or remove lead paint yourself without proper training, equipment, and containment measures
• Consider encapsulation or enclosure methods, which cover lead paint with new materials rather than removing it—often a safer and more cost-effective solution

LBP Survey

If you question if lead-containing building materials are in your home, a Lead-Based Paint Survey will assist you in knowing for sure.   Surveys are like LBP inspections in that an electronic lead paint analyzer is used on-site to test for the presence of lead. Curren utilizes a SciAps X-550 X-Ray Fluorescence (XRF) Lead Paint Analyzer to determine the lead content of the painted surfaces. The XRF will determine if lead exists on the component tested (within seconds); if the test is positive, the condition of the component is evaluated. Even if lead paint is detected via the XRF, the condition of that paint will determine if further action is warranted. 

Can you think of anything more boring to talk about than a crawlspace?  Tough to keep readers after that statement, but wait one minute.  Crawlspaces are important because:

1. As much as 50 percent of the air inside your home comes up from the crawl space.
2. Crawlspaces, attics, and unfinished basements are the 3 most common areas to find mold in a home.
3. Many Crawlspaces have HVAC ducts that can pull air from the crawlspace into your home. If the crawlspace isn't clean, neither is the air inside your home.
4. Damp crawlspaces will breed termites, spiders, ants, and other insects.
5. About 90% of crawlspaces we evaluate are in need of attention.

Here is the good news: Curren consults on environmental building issues, and I can explain both the DIY crawlspace management as well as hiring a company to address the crawlspace.    To be objective, both DIY and professional crawlspace management can have VERY similar results; the thousands of dollars between the two rarely justifies the marginal increase professional management achieves.

Water proofing (ahem, water management) companies that do crawlspaces will not want you to read this.

Why do Crawlspaces have mold growth?

Traditionally, builders either insulated the floor above the crawlspace or left it uninsulated, while keeping wall vents open for ventilation. This approach assumed that vents would remove moisture, but in humid climates, they actually allow moist air to enter. When this air contacts cooler crawlspace surfaces, condensation forms. This process often results in drooping insulation and mold growth on exposed wood.

Crawlspaces are typically cooler and less humid than outdoor air during summer, which draws moisture inside. Humid air then condenses on cold wood and concrete surfaces, creating a persistent moisture source. This design results in a high likelihood of mold growth, with a 90% probability.

 A crawlspace will, by nature, be cool in summer and less humid than outdoor air, so moisture and humidity will be drawn to the space, allowing the humid air to condense on the cold surfaces of wood and concrete in the crawlspace. This provides a continuous source of moisture in the crawl space.  This type of design has a 90% chance of allowing mold to grow.

This photo shows a crawlspace that has ATTEMPTED to control moisture; there is a black poly vapor barrier on the floor.  But if you look closely, you can see it doesn't cover the floor 100% (there is exposed soil).  There are also open vents that you cannot see.  Bottom line, the poor management of moisture is allowing mold to grow; you can see the white staining on the wood.

On a basic level, humidity is a real driver of mold growth in a crawlspace, but you can also have other sources. Physical water intrusion, gutters, plumbing leaks, as well as improper exterior management, can be contributing factors.

The historic design of a crawl space creates a perfect environment for mold. It has oxygen, it is dark, there is ample food (dirt, wood, insulation, animal waste), and as discussed, the temperature and humidity level create the perfect ecosystem for mold growth.

Crawlspace Management

Exterior of the Crawlspace

If you want to have a well-maintained crawlspace, let's start with easy to hard things you can do.  On the exterior perimeter of the crawlspace, all soil should be sloped away from the foundation, allowing water to flow away, not toward the crawlspace.   I would say 60% of inspections find the exterior grading in need of improvement.   Next, your roof leaders (gutters to the layperson) should have 5' to 10' extensions so rainwater flows far away from the foundation.  Understand that water in the soil around a foundation and even the masonry foundation will draw moisture into the crawlspace, so reducing the water around the foundations also decreases moisture in the space.

The easiest way to know if you need to do any of this is to actually go into the crawlspace when the weather is nice and again after or during a rainstorm to see if you are getting water entry.  You can also walk the exterior with an umbrella when it's raining to see if water puddles near the foundation; those are the problem areas.

Interior of the Crawlspace

There are three things you need to do to reduce moisture inside the crawlspace. 

First, seal all exterior vents in the foundation; this can be performed with rigid foam board, cut to fit.  Spray foam can be added along the edges to really seal the opening.   When you have the can of spray foam going, seal any penetrations in the foundation where you can see sunlight entering, like for hose bibs, utilities, etc.   You can also install plates on the outside of the foundation, like the photo to the left.  It's best to do both, as the foam board also insulates the opening.  An overlapping layer of plastic sheeting is placed on the floor of the crawlspace.  Home Depot sells a 6-mil roll of poly sheeting, 20' by 100', for $127.  You can use bricks to weigh down corners and along the seam.   A double layer is best; the hardest part is having to cut around internal supports in the space.

Install a dehumidifier with tubing that allows it to drain outside the crawlspace.  You will need electricity and installation in the approximate center of the space is best.  Every three months, you must pull out the screen and run it under water.   The photo to the left is a screen the owner never knew existed.  For a baseline, if you hold a clean screen up to your face, you can see through it; this one failed.

This DIY fix, excluding your labor, is approximately $1,000.00.  This is with about $300 in plastic, $350 for a decent dehumidifier, and the balance for other materials.  Larger spaces will cost more in materials. This assumes you have an outlet in the crawlspace to plug a dehumidifier into; otherwise, you need an electrician.   

Naysayers will tell you this approach doesn't 100% air seal the space. Well, guess what, none of them do.  Does every person use a dehumidifier in their basement?  It runs right? collects water, and your basement has walls? a floor and a ceiling?  Is it pretty sealed?  But not 100% apparently.

Pro Tip: If you are going to address your crawlspace for moisture, you should also address mold that likely formed before your fixes. Mold Remediation

Mold remediation of a crawlspace will remove existing mold and future-proof the space by applying a fungistatic coating (mold inhibitor) to the wood, which is the mold's food source.  Mold-resistant coatings have 10-year warranties to prevent mold growth on the surfaces where it is applied.  But in practice, you will be dead before mold grows on it as UV light breaks it down which your crawlspace doesn't receive.

Professional Crawlspace Management

You just received professional advice on managing your crawlspace.  But maybe you are physically unable to perform the recommended tasks.  Google "crawlspace management", scroll down about 8" on the page, scrolling by all the companies that are paying for placement of their ads, and look for organic search results.

• Installing a Vapor Barrier: A thick (typically 8 to 20-mil) polyethylene liner is installed across the entire floor and up the foundation walls and piers to help minimize moisture from entering the space.
• Sealing Foundation Vents:  Crawl space vents, air leaks, gaps, and cracks around plumbing and wiring penetrations are sealed to prevent unconditioned outside air and pests from entering.
• Insulation of foundation Walls: Foam board insulation is often installed on the interior foundation walls to stabilize temperatures and improve energy efficiency.
• Humidity Control: Installing a dehumidifier to remove any remaining moisture from the air and maintain optimal humidity levels (ideally between 45% and 55%).
• Drainage (if needed): In cases of active water leaks or potential flooding, an interior drainage system and a sump pump may be installed to remove standing water before it becomes an issue

The photo to the left shows a crawlspace with a vapor barrier on the walls and floor.  

Some companies will extoll the virtues of a conditioned crawlspace, meaning HVAC vents in the space are open to heat and cool the space.   Not a huge fan of conditioned crawl spaces since you are heating and cooling an area that is not habitable. 

The photo to the right is another crawlspace, which had a concrete floor;  no vapor barrier was needed.  The walls were insulated with foam board, and the outside vents were sealed.  This is a much cheaper approach, but really,  it could have been a $100 fix by just sealing the vents.  Here is what you do not see but should visualize:  that there is zero mold in this space, nor was there ever; the owner told me so as they paid for the insulation on the walls.  They are elderly, and they said they were told it was dangerous not to do the insulating - scammed. 

Want professional advice on a crawlspace? Call Curren.