What Is the Best Way To Insulate a Crawl Space With a Dirt Floor?

The main challenge of crawl spaces with dirt floors is the penetration of outside moisture and underground water into the house. These elements expose your home to water damage and mold growth. Therefore, insulating your crawl space with a dirt floor is the best way to protect your home from water damage and mold.

The best way to insulate a crawl space with a dirt floor is to encapsulate it with a heavy-duty barrier that can withstand foot traffic and movements. Such a barrier prevents the evaporation of underground and outside moisture into the home.

In the rest of this article, I’ll take you through insulating your crawl space with a dirt floor. I’ll also cover the benefits of protecting a crawl space with a dirt floor. 

Encapsulate the Crawl Space With a Heavy Duty Barrier

Encapsulation works hand-in-hand with a dehumidifier in the crawl space to ensure low humidity levels, irrespective of the season.

Encapsulation creates a building envelope that separates the conditioned space of your home from the unconditioned crawl space. This envelope usually contains a vapor barrier, an airtight seal, and insulation.

You can use different materials to create this encapsulation, but the most common are:

  • Visqueen
  • Polyethylene sheeting
  • Polyurethane

The following process will help you encapsulate your crawl space with a dirt floor correctly:

Read: Is It Ok To Have A Furnace In The Crawl Space?

How To Insulate Your Crawl Space Through Encapsulation?

There are several steps to take to conduct a successful encapsulation of your crawl space. These steps are essential to ensure that your crawl space is correctly insulated and that you won’t experience any problems further down the line. Let’s get started!

Eradicate Mold, Drainage, and Combustion Issues

Some crawl spaces are not ready for encapsulation due to molds, drainage, and combustion failures. You must ensure:

  • The crawl space has sufficient foundation drainage. Poor drainage in the foundation makes it easy for underground water to seep into the crawl space.
  • No mold exists in the crawl space. Clean all the mildew from your crawl space, if any. This process is to prevent the encapsulation material from trapping moisture and mold.
  • There is no back drafting from combustion appliances. If you have a furnace, water heater, or any other combustion appliance in the crawl space, ensure that it is not back drafting.

Install a Crawl Space Vapor Barrier

The most common way to encapsulate a crawl space with a dirt floor is to install a vapor barrier on the ground. This barrier prevents moisture from evaporating into your home. Some ways to achieve this are:

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  • Adding a plastic vapor barrier to the crawl space’s floor: A vapor barrier keeps moisture from the ground of the crawl space. However, you must ensure that the plastic barrier is attached to the piers and foundation walls.
  • Install a thermal barrier to the walls: You must prevent outside moisture from entering the crawl space. The best way to do this is by attaching a thermal barrier to the crawl space’s walls. Foam insulation is an excellent thermal barrier.

Read: What Size Dehumidifier Do I Need For My Crawl Space?

Install an Airtight Seal Around Openings

After you’ve installed the vapor barrier, you need to create an airtight seal around all openings in the crawl space. This barrier stops outdoor air from getting into the crawl space. 

You can use different materials to create this seal, such as:

  • Caulking
  • Foam insulation (spray foam)
  • Weatherstripping

Your focus should be to:

  • Seal all vents and openings to the outside: Sealing vents to the outside prevents humid air from getting into the crawl space and worsens the situation. 
  • Air-sealing all gaps and cracks: You must pay attention to holes like band joists, plumbing penetration, wiring, and drain line runs. Such gaps, if left unsealed, will allow humid air into the crawl space.

Maintain a Dry Environment in the Crawl Space

Vapor, air, and thermal barriers don’t work alone to keep the crawl space insulated throughout the year. You must aid these barriers in maintaining low humidity in your crawl space. The best way to do this is by using a dehumidifier.

A dehumidifier removes moisture from the air and keeps the relative humidity (RH) levels in check. The ideal RH level for a home is between 30-40%. You can use a hygrometer to monitor RH levels in the crawl space.

It would be best if you positioned the dehumidifier near the supply ductwork to work efficiently. Moreover, it would help if you had the right size dehumidifier for your crawl space. A good rule of thumb for the right size of dehumidifier is the smaller the crawl space, the smaller the dehumidifier, and vice versa.

The device will have to work overtime if you choose a smaller dehumidifier for an ample crawl space. This process leads to more energy consumption and a shorter lifespan for the dehumidifier.

Holding Water and Moisture Back

Holding back water and moisture is another way to insulate your crawl space with a dirt floor. Water and moisture are the main culprits for water damage and mold growth. According to The United States Environmental Protection Agency, mold spores can’t grow without moisture.

It’s worth noting that a dirt floor can absorb water or moisture and release it into the crawl space. That’s why you must find a way to hold back this moisture. The best way to do this is by installing a drainage system and sump pump in your crawl space.

You should install a sump pump at the lowest point of the crawl space. It removes accumulated water in the sump pit and pumps it out of the crawl space.

A drainage system, on the other hand, is a network of pipes that diverts water away from your home’s foundation. You install this system around the perimeter of the crawl space.

The two work hand-in-hand to keep your crawl space dry. Moreover, the combination prevents hydrostatic pressure from building up and causing cracks in your foundation.

Read: Do Dehumidifiers Use A Lot Of Electricity?

Steps To Take After Installation

Once you’ve installed the drainage system and sump pump, there are a few steps you need to take to ensure that they’re working correctly:

  • Check the system regularly. Check for any leaks or cracks in the pipes. Moreover, ensure that the sump pit has no debris that could clog the pump.
  • Clean the sump pump. Remove any residue that might have accumulated in the sump pit. This process will ensure that the pump can work correctly and doesn’t get damaged over time.
  • Test the system regularly. Test the system by adding water to the sump pit and ensuring the pump kicks on.

Benefits of Crawl Space Insulation

Insulating your crawl space is among the best decisions you can make for your home and family because:

  • It prevents molds: According to Rhode Island’s Department of Health, exposure to mold spores causes sneezing, watery eyes, coughing, wheezing, itching, difficulty breathing, and fatigue. You can prevent these issues by insulating your crawl space to prevent moisture penetration into your home.
  • Prevents water damage: Water damage is one of the main problems uninsulated crawl spaces face. Water can enter through the dirt floor, cracks, and gaps in the foundation and cause severe structural damage to your home.
  • Energy efficiency: An uninsulated crawl space lets heat escape, which forces your HVAC system to work overtime—leading to higher energy bills.
  • Prevents pest infestation: Pests are attracted to uninsulated crawl spaces because they’re dark, humid, and full of cracks and gaps. You make your home less attractive to pests by sealing these off.

Read: Can You Install A Furnace Yourself?

Final Thoughts

Crawl spaces are essential as they support the living areas by providing a buffer between the house and the ground. However, these spaces can cause various problems, from mold and mildew to water damage and pests if left uninsulated. 

Therefore, you should ensure you insulate your crawl space by either encapsulation or water control to protect your home and family from potential hazards.