Sealing a Crawl Space: Pros and Cons

Written by Blake Heron on . Posted in .

Have you walked through your Virginia or North Carolina home and wondered where the moldy smell came from along the flooring? You know the smell impacts the air quality in the house as you fear that the musty odors could slowly cause health problems. If your home has a crawl space, this area may trap moisture and humidity under the floors. The issues may slowly escalate as you debate the benefits to crawl space encapsulation.

The home’s crawl space allows you, HVAC technicians, plumbers, or electricians to access pipes, wiring, and ductwork under the house. You may also use the area as storage space. Unfortunately, the empty space allows moisture to seep up from the ground. Combining moisture with the humid Virginia climate turns into the perfect conditions for mold growth.

Also, the trapped humidity causes fluctuating temperatures in every room. Constantly turning up the furnace or air conditioning does not solve the problem and only creates higher energy costs. Another problem homeowners experience with crawl spaces involves spotting the telltale signs of insects and rodents nesting under the home.

Crawl space encapsulation offered by BAY Crawl Space & Foundation Repair provides an affordable way to deal with humidity, moisture, and pest infestations under your home. Our services prevent the moisture and humidity from entering the crawl space and coming up through the floorboards. The encapsulation also becomes a barrier against humidity, which lowers cooling and heating costs. Have our experts come out today to inspect your crawl space for signs and mold and to determine if encapsulation would improve your home.

What is Crawl Space Encapsulation?

Crawl space encapsulation involves a multi-tiered sealing system that provides a barrier between the ground, air, and the floor’s wooden structure. The technicians place down a heavy vapor barrier liner that covers the entire ground under the home and around support pillars. They tape down the vapor barrier to create a 100% seal. The workers also install a special vapor barrier foam board along the crawl space’s walls.

After installing the vapor barrier liner and foam board, our technicians seal up all the vent covers as well as any door openings leading into the crawl space. Lastly, they set up a dehumidifier that runs automatically to keep the air dry and at a constant humidity range of under 60%.

This multi-tier encapsulation system works by tackling every issue impacting crawl spaces: humidity, moisture, HVAC energy loss, and mold. It is ideal for homes located in humid areas, such as coastal Virginia and Northeastern North Carolina, that experience increases in humidity and salt water. By tackling these issues, the encapsulation prevents quicker deterioration within the crawl space area.

Is Sealing a Crawl Space a Good Idea in Virginia?

With crawl space encapsulation, this process creates heating and cooling cost savings on a yearly basis. Air from within the crawl space enters and exits the home, impacting the conditioned air that makes your home comfortable for your family. In the winter, the cold air draws out the warm furnace heat from your home. Meanwhile, the cold air escapes and mixes with the outside air in the summer, causing higher room temperatures. You end up using your furnace and air conditioning more often, raising your utility bills.

After encapsulating the crawl space, it creates an insulated barrier under your home. The materials prevent airflow from outside from getting into the area. If you have HVAC ducts under the home, the barrier maintains the desired temperatures of the conditioned air moving through the ducts. So each room of the house is heated or cooled optimally as your furnace and air conditioning do not have to work overtime.

In addition, the high humidity and moisture levels build up underneath the house and may ruin the floorboards. Vapor rises from the ground as drafts from crawl space entrances that lead outside blow the dust, gasses, and even mold or fungal spores into the vapor. Then the vapor rises as the moisture clings to the wooden structures, allowing the spores to attach to the wood. With the constant vapor and mold, the wood can deteriorate faster and lead to cracks that allow more of the contaminants and allergens to enter deeper into the wood.

Mold, mildew, and fungal growth thrive in dark and moist environments. Crawl spaces provide these factors that may lead to mold and fungus taking root and eventually getting into your home to negatively impact indoor air quality. Obtaining encapsulation services allows you to have a 100% sealed crawl space that prevents the soil’s vapors from rising into the home.

What are the Benefits of Crawl Space Encapsulation in Virginia?

While we mentioned previously that sealing a crawl space may offer energy efficiency and a way to control humidity levels and moisture, you may find additional benefits from the encapsulation process. Crawl space encapsulation also deters rodents, insects, and other vermin from nesting underneath the house.

Pest Prevention

Dark and safe spaces become an ideal breeding ground for rodents that may chew holes up through walls to enter the home. They can squeeze through the smallest of cracks and through crawl space entrances to live under the floorboards. Then they take the opportunity to get inside your home to look for food. Also, rodents can chew through wiring which could lead to costly electrical damage and potentially dangerous short circuits that could cause fires. By encapsulating the space, you deter pest infestations and make the environment undesirable for rodents.

Protection from Wood-Eating Insects

Termites and other creatures that feed on wood thrive in damp and moist areas. They may enter through cracks along the perimeter of the house or through exterior crawl space doors.

Once inside, the termites and wood-burrowing insects begin to nest and multiply as they also eat the cellulose in drywall. They will continue to feed and reproduce within the wooden joists, severely damaging the wood. This issue may lead to serious structural integrity instability that can become costly to fix. Preventing the moisture from penetrating the floorboards and other wood structures helps to safeguard your home from these pests.

Foundation Protection

Moisture issues and wet ground conditions may also negatively damage foundations. When the ground absorbs water without drying it, it may shift and settle. This shifting could cause foundation cracks and structural damage created by the damp crawl space.

Settlement of the soil can happen for a variety of reasons. The wet soil may compact. Compaction happens when enough moisture builds up between the dirt particles while forcing the air out. This factor causes the dirt particles to slide together as they compact. As the wet soil compacts, it takes up less space and causes your home’s foundation to move.

Poor drainage can become another serious problem. Typically, the ground around your home is graded to encourage rainwater to move away from the foundation and to prevent water from pooling. For homes with sloped grounds, poor yard drainage, or redirected water from gutter systems, excess moisture instead enters the crawl space. With an encapsulated crawl space, along with exterior house grading and drainage services, the ground stays dry and firm.

What Are the Negatives to Sealing a Crawl Space?

Many homeowners wonder if there are negatives to crawl space encapsulation. The only major downsides to this process involve the initial expense for installation and the continual maintenance cost to keep the encapsulation in good condition.

For initial installation, contractors base the cost figures on the size of the crawl space, condition of the space, the needed materials, and the labor. The contractor may also add on some additional installation fees for foundation maintenance or repair fees if they discover damaged pillars or wood structures. You may also decide to add additional systems at the same time to further help keep the soil dry. If you are dealing with excessive groundwater or poor drainage, you may also install a sump pump, foundation insulation, and/or drainage trenches. Yet keep in mind that the contractor’s costs are one-time only fees.

Another disadvantage involves the continual maintenance costs for the dehumidifier or other systems (sump pump or drainage trenches). The dehumidifier should undergo periodic inspections every year and repair if workers find any operational issues. You should also have yearly inspections to ensure that the encapsulation system is still in working order and sealed properly.

Keep in mind that the initial and continual maintenance costs may still be cheaper than the repair costs that you will deal with from pest infestations, mold growth, wood rot, and foundation cracks or settling. Comparing the installation and maintenance costs against these repair costs and the potential energy savings may help you decide if this service is the right option.

What is the Cost to Encapsulate a Crawl Space in Virginia?

The initial cost of crawl space encapsulation may range anywhere from $6,500 to $25,000. The national average costs dwell in the middle of this price range at $11,000 which also includes the contractor’s expenses for labor and materials. Several factors determine these costs, such as the size of the crawl space, the condition of the existing wood structure, material quality used for the encapsulation process, if foundation wall insulation is required, and the necessary permits and inspection costs to ensure the work follows all building codes.

Crawl space repair costs to fix anything underneath the home before the encapsulation work begins becomes the biggest money factor for homeowners, followed by foundation proofing, drainage systems, and dehumidifiers

A contractor may also offer additional maintenance costs for any foundation repairs, mold remediation, pest removal, or mechanical servicing. The costs may vary depending on the company’s services. While BAY Crawl Space & Foundation Repair tries to provide a close estimate of the crawl space installation, always be aware that costs may increase if any unforeseen circumstances occur during the installation process that may require our contractor to use more labor, order additional materials, or perform other repairs.

Is There an Alternative to Crawl Space Encapsulation?

Yes. BAY Crawl Space & Foundation Repair may suggest a vapor barrier for homeowners who are hesitant to get crawl space encapsulation or who are looking for cheaper alternatives. Our installers place plastic sheets that are moisture-resistant throughout the crawl space. The vapor barrier comes in thicknesses of 6 to 20 mil (1 mil = 0.001 inches). It covers the ground yet does not become installed over the walls.

Homeowners take advantage of lower material, labor, and installation costs when placing in just a vapor barrier. A vapor barrier does offer some damp protection as it keeps the soil’s moisture from reaching the home’s wooden structures. However, since our contractors do not install a vapor barrier against the walls, your crawl space does not gain a complete 100% seal that encapsulation provides.

Encapsulation materials come in thicker plastic liners ranging from 12 to 20 mil. The plastic materials have a reinforced polyester core designed to provide added water protection to the crawl space. Our installers place the materials over every inch of the crawl space such as the floor, walls, and any pillars. Then they tape the sheets together to create a complete seal along the seams.

Keep Your Crawl Space Free of Expensive Maintenance Repairs

Are you interested in crawl space encapsulation for your home? Reach out to BAY Crawl Space & Foundation Repair. We have two locations in Norfolk and Newport News, Virginia as our foundation experts can talk with you about your encapsulation project. Call 757-301-5088 or fill out the online contact form, and we will get in touch with you.

Blake Heron

Written By Blake Heron

Blake has specialized in crawl space & foundation repairs for over 10 years (since 2012). His prior engineering and business degrees from James Madison University in VA prepared him for a mastery of problem solving with crawl space & foundation repair issues. He is one of America’s top experts on crawl space encapsulation. As Founder of both ‘BAY Crawl Space & Foundation Repair’ as well as ‘GridLock Foundations’ he is a leading industry expert on crawl space foundation repairs.


Call: 757-460-0444
Or Click Below

Request Your Free Inspection