Crawl Space Air Quality
Crawl space air quality is affected by the inadequate ventilation to the crawl space where there is a meeting of warm and cool air (6) (7). There is usually an increase in relative humidity (8) in that area, which in most cases is above 100% (9), which can influence the crawl space air quality. This is a problem not only because of regular pandemics (2), but also common flu (1), stack effect (5) and the detection of radon gas in the soil (11), wherein studies have linked radon exposure and lung cancer (3) even in non-smokers (4). It has been found that the humidity will change into water once it gets above 100% (10), usually causing condensation on cool surfaces (12) (13). Therefore, we will indicate how to keep humidity in a 30% to 60 % (14), leveling out at an average of 56% to avoid mold (16), or even less than 50% according Oxford (15).
Crawl space air quality issues arise from inadequate ventilation.
Let us begin with the foundation, or, more precisely, the crawl space. To be quite honest, a ventilated soil floor crawl room is a terrible idea. The arrangement is faulty, resulting in a reduction in the quality of the indoor air in the house above. A home built on top of a crawl space serves like a massive sponge, absorbing moisture from the surface.
The soil in a crawl space is often drier than the ground surrounding the foundation. As a consequence, moisture from the soil outside wicks into the crawlspace area. Once within the crawlspace, moisture evaporates into the air and water vapor rises to deposit on ducting, floor joists, subfloor, and floor insulation.
Generally, the air and surfaces within a crawl space are cooler than the air outside during the summer. Since warm, humid air enters a crawl space through foundation vents, it cools, resulting in a rise in relative humidity, as heated air can retain more water vapor than cool air. Condensation accumulates on ducts, floor joists, subfloor, and/or floor insulation, which promotes mold development.
Much of the current interest in air quality may be attributed to the emergence of novel viral strains and our desire to prevent infection. In the past decade or so, there have been a number of significant worldwide pandemics and regular epidemics.
Crawl Space Air Quality Issues
During the warmer months, warm, damp external airflow enters your crawlspace and condenses on colder crawlspace surface, providing a perfect habitat for mold, allergies, and dust mites to thrive.
Additionally, excessive moisture adds to the decay of wood over time. Damp wood attracts insects such as termites as well as carpenter ants and other critters, whose colonies wreak havoc on the structural integrity of your home’s woodwork.
Fiberglass insulation is readily absorbed by moisture, causing it to droop and collapse to the bottom of your crawl space. Winter months add extra complications since your home’s flooring depend on insulation to stay warm, but when it comes to insulation, it has been compromised due to the high moisture content, resulting in a higher heating expenditure.
Undesirable odors, mildew, ceiling and wall condensation, bug infestations, and unanticipated allergy-like symptoms are all indicators that your home’s crawsl space air quality has been compromised by its poor maintenance.
Relative Humidity (RH) is the amount of water in the air relative to the maximum amount of water the air can hold at a given temperature. The higher the RH, the higher the moisture content in the air.
A low level of indoor air quality produced by high indoor relative humidity levels (RH level) may result in a variety of issues that have an effect on your house and the people who live in it. Crawl spaces, which have high relative humidity, are ideal breeding grounds for dust mites and insects. According to the Environmental Protection Agency, dust mites are the most commonly reported cause of indoor asthma episodes.
Evaporating moisture, whether it comes from stagnant water following a sustained rainfall or just from the ground, may cause damage to wood and insulation, and it can ultimately find its way into your house. Mold growth in the crawl space and upstairs living spaces is a frequent issue that is caused by an excessive amount of moisture in the home.
Mold and mildew thrive in dark, humid environments, and damp air encourages their growth. Mold reproduces by releasing spores into the atmosphere. Mold spores are a significant allergen, and inhaling mold spores has been associated in the past with an increased chance of developing asthma in the past.
When mold develops, it produces mycotoxins, which may infiltrate into your house through the floorboards and cause illness. Mold is also difficult to cure because mold spores spread through the air, occupying any area where there is moisture.
Subflooring can become quite distorted as a result of moisture accumulation, and the structural integrity of your home can be compromised if it is subjected to high levels of moisture, condensation, and humidity on a regular basis. For this reason, it is critical that you take care of any crawlspace you have as though it were a normal part of your home.
The management of moisture is one of the first stages in having a crawl space that is pollution free and hygienic. In an ideal situation, moisture should be able to return to the atmosphere through evaporation. When moisture condensation collects around wood, it creates an environment in which mold and mildew may thrive. Your home’s structural integrity may be jeopardized if left unattended. Making certain that exterior water sources, such as your gutter system, are diverted away from your house may help prevent your crawlspace from becoming wet. In addition, raising the soil levels so that water may be able to drain freely from the house is a smart idea as well.
It is possible for water to find its way into crawlspaces as groundwater rises after heavy rains, or even via capillary action, in which surface tension pulls water through the soil and straight into your crawl space. Furthermore, if your crawlspace happens to be located below the water table line, you may have difficulties. Whatever the cause, it is critical to identify the root of the issue and rectify the situation. Standing water in your crawl area is harmful to your home’s environment because it encourages excessive moisture, mold development, and, in certain cases, bugs and other animals to enter. This noxious air will find its way straight into your home, where it may have a negative impact on your family.
Service providers may provide you with a drainage system for your crawl space that will help manage the amount of water in the area and prevent floods from occurring. It is also possible for them to build an encapsulation system, which would transform your crawl space into a brighter, cleaner, and healthier storage area.
And here is where we start to connect all topics together: how moisture affects the crawl space air quality and what can we do to solve it.
To allow for the evacuation of heated air, homes are ventilated via the roof. Warm air from inside your house rises and gradually exits via the roof. Simultaneously, air is drawn into your house from the crawl area underneath. The stack effect is a mechanism that draws moisture from the ground into your house. Condensation, mildew, fungus, musty smells, and, most importantly, a hazardous environment may occur in damp crawl spaces. Crawl space dampness promotes mold growth and spore release. A damp crawl area will continuously flood your house with microscopic mold spores that are floating through the air and are invisible to the naked eye.
There is a high possibility that spiders, reptiles, whiteflies, rats, rodents, or even termites may establish a home in the shaded, wet crawlspace below a house, especially if there is moisture. Moisture-induced rot and decay may cause structural damage to your house. If you have mold, you almost surely also have dust mites in your home.
How can crawlspaces become so humid? Rooftop rainwater may be dripping into your house. During a one-inch rainfall, a normal roof may generate up to 1,100 gallons of water (4100 liters, approximately). If this rainwater is not adequately directed below the surface of the property, it may flood the soil around it. Summer watering of the landscaping and flowerbeds may generate an excessive amount of moisture near the foundation. If your house is situated on a gradient, and collect near the foundation. Even if there is no standing water, this wet earth will evaporate into your crawlspace, as stated above via capillary forces.
The presence of moisture in the crawlspace area attracts spiders, rodents, vermin, reptiles, insects, and other nefarious creatures. Due to the fact that the crawlspace is often left unattended, it offers a secure refuge for animals in need of a comfortable home. Pathogens in rodent feces and urination may contaminate the air in your house.
Dust mites are the primary cause of indoor allergies and asthmatic episodes, according to the EPA. Due to the fact that dust mites flourish in humid settings, crawlspaces end up being an appealing breeding site, posing a threat to homeowners.
Once the crawl space air quality is analyzed, it can be defined that you require to have a radon mitigation system installed. This is not common as most of the crawl space air quality issues can be solved through vapor barriers, encapsulation, and probably the installation of a dehumidifier system.
Although radon gas is invisible and odorless, it is present in nearly all soils. It results from uranium’s decomposition process and travels upward through the earth, into the air above, and ultimately into your house. Radon exposure has been related to lung cancer in research. Indeed, Yale reports that radon is one of the leading cause of lung cancer among non-smokers (EPA).
You may be worried about the presence of soil gases in your crawlspace, or maybe you have had already had a foundation inspection that confirmed the presence of ground gases in your crawl space, including this item in the inspection checklist.
Considering that subsurface gases may be hazardous and even deadly, it is critical to take measures to minimize the possibility of them being released into the crawlspace region. Whatever impacts the crawlspace environment will have an effect on the living conditions in your property as well.
Because EPA recommends testing for radon on the lowest lived-in level of a home, even if you’ve previously tested, if you have not tested in the basement, you should test again. Because fixing a radon problem will usually be easier and less expensive before the basement is finished, you should test before you begin your remodeling project.
4. Air Filtrations From The Exterior
Even though the majority of crawl spaces consist of vents, these systems are still essentially passive, which means that the ventilation happens solely as a consequence of pressure fluctuations and airflows through the vents.
Not many crawlspaces are equipped with motorized ventilation systems, that might provide an entirely different set of problems of their own. Stagnant air accumulates as a consequence of insufficient ventilation. Mold, radon, and moisture (which is attracted to a variety of pests and is also a magnet for rats) may accumulate to hazardous levels in this environment.
Warm air trapped within a house rises and exits via the attic, attracting cooler air from lower levels, including outside air and crawl space air. By utilizing exhaust fans in the kitchen and bathroom, a negative pressure is created inside the house. Additionally, this negative pressure pulls in air from the outside of the house and from the crawl area.
It is likely also that your foundation is not entirely airtight, and this is fine. In fact, most houses have ventilation systems installed so that fresh air can circulate easily.
However, this can contribute to damaging the indoor air quality by allowing pollen, dust, and other microbes from the outside to get into your home through the wind. As the filter in your HVAC system may assist in removing these particles, keep in mind that this is only while it is in operation. The remainder of the day, these allergens circulate freely throughout your house.
If indeed the oxygen outside is more contaminated than the oxygen within the property, venting into the crawlspace would enable this contaminated external airflow to enter the crawlspace and ultimately into the house. Poor air quality may aggravate allergies, asthma, and other respiratory problems.
5. Ducts And HVAC Systems Installed In The Crawl Space
Your crawlspace area may serve as an open-air superhighway, transporting all of the dust and dampness as well as rodent droppings and pollutants from the crawlspace through your living quarters and into your indoor air.
It is common practice to install HVAC equipment in the crawlspace, which is usually considered a poor idea. and at the duct boots may be found in almost all HVAC systems, even many newer installations. Because of these leaks, the system’s effectiveness is reduced, and filthy crawlspace airflow is permitted to enter inside your living space.
Despite the fact that the crawlspace does not constitute a part of your living quarters, homeowners should consider it an extension of the home’s breathing space from the point of view of indoor air quality. The crawl space air quality is affecting your wellness, directly.
It goes without saying that your heating and air conditioning systems are responsible for controlling the temperature in your home. What many of us do not realize is that the HVAC system is responsible for this. It circulates air around your house, heating or cooling it as needed. When it accomplishes this, it is not sterilizing the air; rather, it is simply filtering it. Furthermore, it only filters while the heat or air conditioning is actively operating.
Ducts that are properly placed and sealed should not be a problem, but the truth is that ducts in the crawl space are often improperly installed and unprotected from the elements. Condensation issues may occur when cold air is forced into a damp crawl area via ducts.
6. Vapor Barriers That Allow Airflow Infiltration
Crawl spaces with a real floor are very rare. There is a general tendency for crawl spaces to have dirt-covered surfaces, which enable water vapor, smells, and pollutants such as radon to infiltrate into your house via the cracks in the foundation. If you have a vapor barrier placed in your house, this may assist to minimize the problem.
Vapor barriers are thin pieces of plastic that are used to cover the soil, but they are not properly sealed along the joints, around the edges, or around columns or pipes. It is usually simply placed carelessly on the surface to serve as a physical barrier between two points.
7. Influence Of The Stack Effect
Warm air rises to the surface, while cold air descends. In the winter, there is a phenomenon known as the stack effect by which cold air pushes warm air upward and out of your house, creating a draft. In the estival season, it has less of an impact on your house, but it is still there and active. The most essential thing to understand for the purposes of this article is that the airflow in your crawlspace area is pulled into and through your house.
The stack effect occurs as a result of excessive amounts of moisture and water accumulating in your crawl space, resulting in greater humidity levels in the area.
Throughout a warm period of time (as the air heats), water vapor is drawn up from the crawlspace through the foundation of your house (subflooring and surface ground floor), which will cause all of the air previously underneath you to remain in your home’s living spaces. Because the moisture from your crawlspace area rises into your house and mixes with the surrounding air, increased humidity levels may result in greater heating and cooling expenses as well as a decrease in the value of your property. It is possible that your crawl area is responsible for up to fifty percent of the air that you breathe inside your house.
As a result of a phenomena known as the “Stack Effect,” as much as 50% of the air you breathe inside your house may come straight from the crawl space, which is a significant source of indoor pollution.
Heat rises and exits via the higher floors of your house, and is replaced by unpleasant crawl space air, resulting in a phenomenon known as “pulling,” which exposes you and your family to poor air quality in the living areas of your home.
Crawl area conditions become wet and damp as a result of water infiltration and external dampness. In response to the rising temperature of the air, it is drawn upward and out of the crawl space, and into the living sections of the house. Strange odors in the house, excessive levels of indoor humidity, and bug infestations are all common consequences of this phenomenon.
Even houses that do not have obvious crawl space moisture issues may suffer excessive levels of humidity within the home as a result of the impact of the stack. This is most often caused by water vapor traveling through the crawl area and flooring of the home. Mold and condensation are two of the most serious problems.
Solutions To Improve Crawl Space Air Quality
In order to effectively seal off the crawl space, a durable liner such as a vapor barrier is recommended, in a process called encapsulation. Thus, a drainage system and a sump pump must be installed as well.
This is the method that we suggest for encapsulating your crawlspace area since it will provide you with the greatest amount of protection from contaminants, will substantially enhance the crawl space air quality, and will sanitize your surroundings.
All that we have mentioned so far will be addressed, and you will have a pristine, and almost sterile environment beneath your residence as a result of the aforementioned “encapsulation”.
Homeowners utilize their now-encapsulated subterranean spaces to store items such as Christmas decorations, out-of-season clothes, and other belongings.
If you have a wet crawlspace, you must handle the problem immediately and ensure that water is drained out of your household as quickly as possible. Using waterproofing, you may gather moisture in your house, capture it, funnel it into the sump pump, and then discharge it out of your residence. Water is diverted away from your foundation, which prevents a number of problems from developing.
Correcting moisture problems may be as simple as redirecting downspout runoff away from the foundation. It may involve re-grading the ground around the house so that it slopes down away from foundation, or venting the dryer to the outside (something that should be done in all homes). Sometimes, however, there are more extensive problems which can be expensive to correct. In any event, the problems should be addressed before you begin other work.
You may begin inspecting and cleaning the crawl space itself once you have removed any external sources of moisture. If you have dirt floors that are exposed to the elements, then perhaps it would be a good idea to seal them with a moisture retardant.
In a dirt flooring, moisture naturally accumulates, which may be drawn upward onto the airflow from the flooring above by the vacuuming action thereof.
As insects and rodents burrow their way through the earth, dirt serves as an entrance point for them.
Cleaning your crawl space on a regular basis may assist to maintain it clean and free of dampness. If your crawl space has already been impacted by things like standing water and/or mold development, it may be essential to bring in a professional to clean it out completely.
The installation of an encapsulating system, together with the installation of an air quality management system, is the most effective way of controlling moisture and smells in the crawl space. This technique also helps to keep the humidity levels from rising too high.
Purchase An Humidifier
If you have followed the previous step and you already have the water surfaces confined and under control, then it is time to remove the moisture from the air in a permanent way.
A dehumidifier is an important component of the overall encapsulation procedure, and it may greatly enhance the crawl space air quality.
Several studies have shown that dehumidifiers are an efficient way to eliminate the risk of viruses spreading throughout your home. At 50 percent humidity, there is a tipping point when things start to become interesting. This is the optimal humidity level for decreasing or eliminating germs, viruses, fungus, mites, and allergies, thus lowering your risks of contracting a respiratory condition or other illness.
Installing an air quality management system will assist in reducing the amount of excess moisture in the air as well as filtering the air that is located underneath your home’s foundation. In the long run, this will help to maintain the air quality in the house above better and avoid the development of mold and mildew in the crawlspace.
In addition to keeping water from harming your crawlspace, the ability to regulate moisture levels and enhance the air quality is the most essential aspect of crawlspace encapsulation. Because a significant part of the airflow in a house will flow up via the crawlspace, it is critical that this airflow is of the best possible quality before entering the living quarters.
People’s general health may be improved by breathing clean air, and it can also assist to avoid the development of mildew and mold in the crawlspace, which can be dangerous.
According to the Environmental Protection Agency, the issue of indoor air pollution has emerged as one of the five most serious environmental health hazards. Among the most common causes of indoor air pollution include construction products, furniture, and furnishings such as insulations, wet carpeting, and certain kinds of furniture, as well as home cleaners, humidifiers, and even pollutants from the outside. It is possible to minimize the effect of these pollutants while also controlling the general relative humidity in your house by installing a crawl space air quality filter and dehumidification system.
The perfect dehumidifier for crawl spaces should be able to maintain the humidity level clearly under fifty percent what will prevent the generation of mildew. Apart from removing the spores of fungus and the excess of moisture, it can perform the purification of the environment.
Encapsulation Of The Crawl Space
By encapsulating your crawl area, you can regulate the relative humidity and avoid outside weather intrusion. This may benefit the general health of your house and everyone who lives there.
The waterproofing technique is the most effective way to prevent having a damp crawl space in the first place. Additionally, encapsulation is included in the process of waterproofing, which is the act of closing off the space to prevent outside dangers from infiltrating it. Licensed waterproofing professionals will evaluate your crawl area to identify the source of the leak. If required, experts may drain water from concrete walls that are retaining it, build a trench to drain the water, and place a sump pump in a catch basin to collect the water and direct it elsewhere.
Encapsulation consists of the installation of a vapor barrier and a water-resistant mat that provides protection for the crawl space against flooding, water damage to be more precise, or other moisture intrusion.
According to the EPA, the most effective method to avoid mold development is to manage moisture. A high-quality vapor barrier may assist in removing moisture from your crawlspace, thus avoiding the development of fungal diseases and mildew that can be detrimental to the state of your pulmonary system.
To maintain appropriate humidity management in the crawl area, it must be encapsulated from the outside air. Then , and only then, is it possible to carry out the process of decreasing the relative humidity.
This is done by laying down a thick plastic barrier (approximately three or four times thicker than a vapor barrier), connecting it to the walls, and sealing all columns, piping, and connections. This will prevent gases from leaving the soil, as well as pollen and contaminants from entering at the ground levels. While encapsulation does not remove the stack effect, it does limit it to a temperature issue. The reason for this is that many of the openings in your foundation are likewise sealed, converting your crawl space into a climate-controlled room similar to the rest of your house.
Encapsulating your crawl space is not the same as waterproofing your basement; it entails the installation of a heavy-duty liner, as well as a specifically engineered drainage system and sump pump to remove water from your house.
Encapsulating your crawl space has a number of advantages and features, among them the following:
- Your home will gain additional storage space with an encapsulated crawl space that is bright and clean.
- It is a helpful action to avoid the effects of hydrostatic pressure in the basement, but it is not the main solution.
- It can protect the floor joists located within the crawlspace, avoiding at least partially, the necessity of sistering old joints of any dimensions.
- Insulation can make a big difference in reducing the energy bills of your home. The use of encapsulation can result in an average of 19% reduction in energy bills.
- Insects, gasses, odors, and moisture are all blocked by the wall and floor liners, improving the quality of the air throughout the entire living space, resulting in a healthier and happier home.
- Your home can be resold at a higher price if you renovate it. Selling a house with water problems could alienate buyers. Having an encapsulated crawl space makes a home more appealing to potential buyers.
- A well-encapsulated room provides better indoor air quality, which makes it easier to breathe.
- By encapsulating the air, humidity is kept under 60%. Furthermore, an enclosed crawl space can prevent the migration of vapor through the air into other areas of your home. A humid environment is often a breeding ground for a variety of bacteria. Maintain a humidity level of no more than 60% in your home, according to the CDC
- HVAC systems can be extended in life through encapsulation. In a conditioned environment, both the equipment and the ductwork will last longer.
- In addition, pest control chemicals are less needed since encapsulation eliminates their use. Although an enclosed crawlspace will not completely eliminate pests, it can greatly reduce the chances of infestations, which often require the use of harmful chemicals in pest control in order to fix the problem. You and your family may develop respiratory illnesses as a result of these chemicals that are spread through the air throughout your home.
Encapsulation Process To Improve The Crawl Space Air Quality
Following the removal of the homeowner’s possessions and the establishment of a rough grade, service providers proceed to the installation of a floor lining on top of the surface, which serves as the foundation for the encapsulation system.
These floor liners aid in the dispersion of soil vapors and the improvement of the drainage of water under the floor liner. An interior wall liner is next installed over the whole floor and walls of the crawlspace in order to completely enclose the space and separate it from the outside environment.
Wall liners must be completely waterproof and should provide a barrier against moisture, gases, insects or smells, and that they will not promote the development of mold. Because they are intended to divert any wall seepage directly into the sump pump unit and drainage system, they may assist you in maintaining the crawlspace air quality.
Water Vapor Barriers
Once your crawl area has been thoroughly cleaned, you may look for any entrance spots that rats may have gained access to and seal them up. It is important to remember that even the tiniest gaps and crevices may serve as entrance points for rats on their journey. It is still necessary to enable enough ventilation in your crawl area. In order to enable crawl areas to vent while still keeping bugs and other undesirable guests out, water vapor barriers are a great option.
Your crawl space may also act as a deterrent to the migration of soil gases if it is enclosed by a thick, high-quality vapor barrier that is properly installed and securely sealed to the outside.
After the ventilation outlets and vapor barrier have been placed, the insulation may be added on top of them. Fiberglass batts such as the R21 are the most frequent and widely used insulating option for crawl spaces, and they may be placed between floor joists to provide additional warmth and comfort.
However, when combined with spray foam insulation, a very tight seal is created that will prevent heat from being transferred through your home’s first level of flooring and also prevent air from moving through, making it a more energy-efficient option.
A small coating of spray foam may be sufficient in order to secure the air in the small cracks and crevices of a crawl space, thus aiding in the retention of warm air and the expulsion of cold air. Styrofoam is also advantageous since it is impervious to moisture, preventing the growth of mold and mildew.
Frequent Change Of HVAC Filters
The federal agency EPA recommends the statement furnished by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Journal. Its text indicates: “A good choice for a central HVAC system filter is one rated at a minimum efficiency reporting value (MERV) of 13 or higher.”
Some readers were asking in the comments section for a solution that was to pour concrete in the floor and have a concrete flooring to eliminate dirt, moisture and improve the crawl space air quality.
I find the idea quite reasonable but I finally discarded it for the reasons I explain below, mostly related to the levels of moisture in concrete, something that I have suffered when I was affected by hydrostatic pressure. Please read my objections in the next three bullet points and let me know in the comments section your opinion.
- The addition of fresh concrete will result in thousands of gallons of humidity being introduced into the already wet crawlspace air (concrete mix is between thrity to fourty percent water).
- In most cases, the concrete is pushed further into crawlspace to a depth of about 2 inches. This kind of concrete will fracture and will have porosity, enabling moisture to penetrate through it and migrate into the upper level of the building..
- The finishing on the injected concrete will not be steel troweled (as is the case with your basement flooring), and it will be rough and dusty at all times, making it filthy.
The majority of crawl space spaces were constructed with vents that enable for the passage of exterior air into the interior. Over the last several years, specialists have discovered that by insulating or encapsulation of your crawlspace, you may remove dampness and smells, as well as gases and an entrance that enables creatures to burrow in your crawlspace. In accordance with the Environmental Protection Agency, a bad crawl space air quality is one of the top five health hazards for those who inhale the air that has permeated from the crawlspace into their living space. Given the fact that up to 50% half of the airflow in your property may originate from below-grade sources, it is critical to ensure that this region is dry and free of hazards.