Crawl Space Encapsulation

Crawl Space Encapsulation – Protecting Your Home and Health

Crawl space encapsulation is a simple technique that improves indoor air quality, reduces energy costs, and can prevent structural damage caused by humidity. Crawl spaces are typically composed of dirt floors, concrete walls, and wood foundations. They are dark, damp areas that attract insects, rodents, and other allergen-inducing organisms. Humidity creates an environment conducive to wood-decaying fungus and promotes mold in crawl space growth, a well-known allergen that can cause a plethora of major and minor illnesses.

Crawl Space Encapsulation – What is It?

Most structures are built with crawl space vents that were once thought to allow humid air to escape from the space. However, new research shows that a traditional crawl space vent, even those built according to current International Residential Codes, can worsen the problem of moisture in crawl spaces.   This is because as humid air enters the space, it is cooled and can cause relative humidity levels to rise to 100%. Since moisture can do so much structural damage and cause serious health issues, controlling the environment is an imperative part of maintaining a healthy home.  (Alternatively, vents can also allow cold air to circulate through the home during cooler seasons, making it more expensive to heat the home. )

crawl space encapsulation

Crawl space encapsulation significantly reduces the humidity level beneath the structure and therefore, the amount of moisture condensing in the crawl space and circulating around the structure. In simple terms, encapsulation involves lining the walls and floors of the space with sheets of a plastic-type material (usually polyethylene) that works to trap moisture and prevent it from entering the crawl space. Plumbing and support features that enter the space through the dirt or foundation are also sealed during encapsulation, leaving only the areas required for proper termite inspection vulnerable to moisture.  Crawl space encapsulation also includes properly venting the space. This can be accomplished through vents that allow air from inside the structure to circulate through the crawl space or by utilizing the air-conditioning system of the home to force air into the area.

Crawl Space Encapsulation – Why it is Important

Moisture traveling through the crawl space and into occupied parts of the structure must also pass through framework for flooring and other structural supports causing wood to soften and decay. “Wood rot” is not only expensive to repair, but can be dangerous for occupants as floors and supporting walls begin to deteriorate. Moist wood provides an environment where fungus that exacerbates rotting can thrive.  As with crawl space encapsulation, a thoughtfully installed crawl space dehumidifier will also significantly reduce the amount of moisture circulating through the space and structural framework. Moisture damage can reduce resale value, cause illness, and make it dangerous to even occupy the structure.  Some homeowners are also vulnerable to radon emissions from the ground beneath the structure. Crawl space encapsulation can help to limit radon and other environmental toxins from entering the home.

crawl space vapor barrier

Encapsulation works because it includes a crawl space vapor barrier that will considerably decrease the number of air-born allergens that enter the living space.  According to some estimates, 40% of the air inside of a typical home was once in the crawl space. So the health of the air inside of a structure hinges on the quality of the air beneath the structure. Crawl space encapsulation is a simple and cost-effective method to reduce the number of allergens living in the crawl space, which will result in better air quality inside of the structure.

Recommended Reading

• Crawl Space Encapsulation
• Crawl Space Vapor Barrier
• Mold in Crawl Space
• Crawl Space Vents
• Crawl Space Dehumidifier

Mold in Crawl Space

Mold in Crawl Space – What To Do About It

Finding mold in crawl space areas is an indicator that the relative humidity beneath a structure is too high. When humidity is allowed to enter and saturate the space, moisture-loving mold will begin to develop fairly rapidly. Crawl space mold is difficult, but not impossible, to completely eliminated once it has manifested into something easily detectable. It is important to note that some fungus in crawl space areas are naturally occurring due to ground moisture. Not all molds are inherently “bad”, but the underlying cause (moisture) can significantly damage the structure. That being said, mold formations that cover the ground or parts of the structure can and should be prevented. Mold on the structure itself should be cleaned to prevent health risks.

The effects of mold in crawl spaces can be moderate to severe; not only is the structural integrity of the home in jeopardy because of the moisture, but serious consequences to the health of the occupants can occur if mold spores are inducted through ventilation systems or updrafts into the occupied part of the structure. At best, headaches, nausea, and common allergy symptoms will develop. However, asthma, fibrosis, and various forms of cancer have also been linked to long-term mold exposure. Prevention is best, but once mold has been discovered in a home, it’s time to take swift action to get rid of it.

Mold in Crawl Space

Preventing Mold in Crawl Spaces

As a reminder – not all molds are bad. There are many natural forms of mold that are purely cosmetic and harmful to neither humans nor building materials. It is advisable to have mold samples professionally tested before declaring a “mold problem” and entering into an arduous, often expensive, process of mold removal. Molds that are cosmetic may be covered up with drywall, insulation, paints, and other aesthetics if necessary. Molds that feed on the materials of the structure or are harmful to mammals need to be addressed.

Before attempting clean-up, one should correct the moisture balance that is causing mold in crawl spaces. There are many ways to address the causes of mold, but one must first identify the cause and conditions surround the mold formation. If the space is commonly damn and humid, crawl space sealing with encapsulation techniques and a dehumidifier might be appropriate prevention methods. If mold in crawl spaces is a new problem, it may be that a pipe leak or damaged drainage system is the culprit. Addressing these issues first will prevent future occurrences.

Cleaning Mold in Crawl Spaces

Once the cause of mold is deduced and addressed, cleansing may begin. Crawl space cleaning requires personal protection equipment (PPE)and a lot of effort. A few basics to remember about mold; it can be airborne, it can get in the eyes, and it can get in the lungs. Cleaning mold in crawl spaces means wearing protective glasses, a dust mask (at minimum), and gloves. While detergent and a scrubbing will remove most surface molds, many varieties seep into woodwork. When mild detergents are successful, mold stains will often remain and can be covered if necessary. There are chemical treatments available for deep cleaning, though many are toxic and require advanced PPE and ventilation for safe application.  However, if mold has been allowed to manifest cleaning may be futile. In severe cases, replacement is the only way to completely remove the mold.  Since it is a laborious task posing significant health risks, hiring a professional cleaning company for this task may be the best way to remedy mold in crawl spaces.

Recommended Reading

• Crawl Space Encapsulation
• Crawl Space Vapor Barrier
• Crawl Space Vents
• Crawl Space Dehumidifier
• Crawl Space Vapor Barrier

Crawl Space Vents

Crawl Space Vents – The Challenges and Benefits

A crawl space vent is built to allow humid air to escape from the foundation of a structure and to allow dry air to enter the crawl space of a structure, thereby pushing humid air out and creating circulation. Recent studies have proven what many builders already know; typical vents for crawl space usage do little to accomplish either of those objectives one-hundred percent of the time. While eliminating vents altogether may be accomplished with encapsulation, there are several techniques that will allow vents to get the job done. In many cases, it will suffice to simply modify the way the air circulates through the crawl space. Assessing the need for ventilation and then creating a solution that is aligned with the temperament of the surrounding climate can negate the need for major crawl space modifications in some cases.

Crawl Space Vents Present a Challenge

In cooler climates, crawl space vents allow cold air to enter the space beneath the structure and can make it difficult to heat the occupied areas of the home. Cool air that enters the crawl space is drafted up and through the structure, finally exiting as warm air through roof ventilation. While this system is working as designed, all of that cool air coming through the home can make it difficult to maintain a comfortable internal temperature.  As a direct result of this flaw in temperature regulation, energy consumption and costs will rise.

Though a purpose is to relieve moisture, unassisted vents in humid climates do little to effectively remove humidity. Studies indicate that crawl space vents built according to International Residency Codes may actually allow more humidity to enter the crawl space if there is high relative humidity outside. High relative humidity leads to condensation that can saturate wood and concrete leading to rot, mold, decay, and fungus. Humidity is also a breeding ground for a myriad of harmful bacteria. Because structures are designed to allow bottom to top ventilation, much of the air in the crawl space will eventually make its way into the home, leaving occupants vulnerable to illnesses cause by the mold, fungus, and various other bacteria.

crawl space vent

Benefits of Improved Crawl Space Vents

Crawl space vent covers were designed to be placed over vents in the winter and can be an integral part of encapsulating a crawl space – a technique that completely seals the crawl space and allows much greater control over the regulation of moisture and airflow through the entire structure. Crawl space venting may also be temporarily capped if an exceptionally cold period is expected for a limited amount of time. Crawl space vents attempt to address an important part of a healthy home, so permanent capping is only advisable if the space is outfitted with alternative venting methods or after professionally installed crawl space encapsulation.

When used in conjunction with fans, vents are a sound method of dehumidifying in dryer climates.  Crawl space ventilation fans work to draw moist air out of the space and greatly improve airflow. Fans are typically motorized vents that replace all or some of the vents in the area. A common technique leaves a traditional vent on one side of the space and placing a motorized fan on the opposite side. This allows the outdoor air to come into the space and then draws it through the outfitted crawl space vent, expelling humid air out on the other side.

Recommended Reading

• Crawl Space Encapsulation
• Crawl Space Vapor Barrier
• Mold in Crawl Space
• Crawl Space Dehumidifier
• Crawl Space Vapor Barrier

Crawl Space Dehumidifier

Crawl Space Dehumidifier – Do You Need to Install One?

A crawl space dehumidifier is an appliance that draws in moist air and replaces it with dry air. Designed for the specific purpose of reducing crawl space humidity, these appliances regulate relative humidity to prevent mold and structural damage due to moisture. Unlike indoor dehumidifiers, crawl space units require properly installed drainage system to allow water run-off to occur away from the crawl space. A dehumidifier is often a component of a larger, more complete crawl space waterproofing system in which the entire space is encapsulated to prevent and manage moisture.

How to determine if a Crawl Space Dehumidifier is Necessary

Ideally, the first step in diminishing moisture is the completion of  a crawl space repair such as replacing leaking pipes, correcting duct work inconsistencies, and repairing improper drainage. Following repairs, initial moisture control can be accomplished with a vapor barrier and proper venting that will further prevent moisture from entering and filtering throughout the structure. If these items have been addressed and humidity or condensation is still problem, installing a crawl space dehumidifier will likely clear up any remaining moisture issues.

crawl space dehumidifier

Other considerations must be made when choosing the appropriate unit to dehumidify crawl space areas; airflow, relative humidity, and drainage are important components to consider. To effectively process the air in a crawl space, the dehumidifier must be able to filter all of the air in that space at least five or six times in an hour. It must also be capable of extracting an effective amount of moisture from the air and then drain properly into a sump pump, the structure’s HVAC drainage system, or another custom drainage system.  If the unit is not powerful enough to circulate all of the air in the space, extract moisture at a rate greater than that in which vapor enters the space, and properly move the moisture away, the crawl space dehumidifier will not provide the required results.

Where to Place a Crawl Space Dehumidifier

The crawl space itself is the prime location in which to install the dehumidifier, provided that the area is large enough accommodate the unit.  Many dehumidifiers are compact and will easily fit into most crawl spaces. However, they may not be powerful enough to treat large areas or spaces in which the relative humidity is exceptionally high. Waterfront structures and those with nearby springs will have a higher relative humidity.

In most cases, the center of the area is the preferred location to achieve maximum results from a crawl space dehumidifier. However, there are instances when this isn’t an option; convoluted spaces, divided spaces, and large areas may prevent ideal placement of the unit. Dehumidifiers with ducting options are ideal in this type of situation. For divided or compartmental crawl spaces, units with ducting can be placed anywhere in the home. The dehumidifier may be placed in a garage or an inside room of the house with ductwork leading to and from the crawl space. Since the primary goal of the appliance is to process enough air and extract enough water to reduce relative humidity, extra effort must be put forth to ensure that ducts are sealed and properly configured. For divided spaces, duct-ready crawl space dehumidifiers will make it possible for the single unit to effectively treat multiple areas of the space.

Recommended Reading

• Crawl Space Encapsulation
• Crawl Space Vapor Barrier
• Mold in Crawl Space
• Crawl Space Vents
• Crawl Space Vapor Barrier