13 Ways for a Clean and Healthy Crawlspace
A clean and healthy crawlspace is an essential part of a house. Clean crawlspace helps to keep the homeowners healthy and maintain structural integrity. To keep the crawlspace clean and healthy, Aqviz experts highly recommend following these 13 ways.
- Waterproof the crawlspace
- Grade the soil around the crawlspace
- Maintain gutters and downspouts
- Install a drainage system in the crawlspace
- Install a vapor barrier in the crawlspace
- Seal foundation vents in crawlspace
- Seal crawlspace air leaks
- Control crawlspace humidity
- Insulate crawlspace walls
- Crawlspace encapsulation
- Add an airtight access door in crawlspace
- Use pest-resistant materials in crawlspace
- Inspect crawlspace twice a year
1. Waterproof the crawlspace
Crawlspace waterproofing helps to keep the crawlspace clean by preventing unwanted water leaks, groundwater seepage, and moisture accumulation that often lead to mold, mildew, pest infestation, and structural decay. A waterproof crawlspace creates a controlled, dry environment that resists the common effects of dampness, such as wood rot, insulation damage, and air contamination.
Crawlspace waterproofing includes sealing foundation cracks, applying liquid waterproof coatings, installing moisture barriers, and directing water away from the crawlspace through interior or exterior drainage systems. As well as you can use waterproofing methods like cementitious, bituminous, EPDM, HDPE, polyurethane, and acrylic for the crawlspace waterproofing. We highly recommend that you install both a waterproofing membrane and crawlspace encapsulation in the highly water-impacted crawlspace.
2. Grade the soil around the crawlspace
Grading the soil around the crawlspace helps to keep the crawlspace clean by directing surface runoff water away from the foundation, preventing pooling, seepage, and ground saturation near the crawlspace walls. Poor grading creates negative slopes that channel rainwater toward the crawlspace. It increases the risk of water intrusion, soil erosion, and foundation pressure. Proper grading is one of the first lines of defense against moisture problems in both vented and encapsulated crawlspaces.
You should maintain a positive slope of the grading at least 6 inches (15 cm) over the first 10 feet (3 meters) away from the crawlspace. This slope ensures that stormwater naturally drains away from the crawlspace instead of settling around the perimeter.
3. Maintain gutters and downspouts
Maintaining gutters and downspouts helps to keep the crawlspace clean by directing roof runoff away from the foundation, reducing soil saturation, and minimizing water infiltration into the crawlspace. When gutters are clogged or downspouts are misaligned or too short, water overflows and pools near the base of the structure, increasing the risk of seepage, foundation cracks, and crawlspace flooding.
We recommend inspecting gutters at least twice a year in spring and fall to remove debris like leaves, twigs, and sediment that obstruct water flow. Downspouts should discharge water at least 5 to 10 feet (1.5 to 3 meters) away from the crawlspace, using gutter extensions or splash blocks. In heavy rainfall zones, adding gutter guards, oversized gutters, and downspout diverters improves performance. Properly maintained gutters always keep the crwlspace clean and free from damage.
4. Install a drainage system in the crawlspace
Installing a French drain system helps to keep the crawlspace clean by actively redirecting groundwater and surface water away from the foundation before it can enter or saturate the crawlspace area. When water accumulates around or beneath the foundation, it increases hydrostatic pressure, which forces moisture through cracks and porous concrete, leading to persistent dampness, mold, and structural issues in the crawlspace.
In order to prevent these crawlspace problems, you can use an interior perimeter French drain, exterior footing drains, and sump pump systems in the crawlspace, but it depends on the property’s grading, soil type, and water exposure.
5. Install a vapor barrier in the crawlspace
Installing a vapor barrier helps to keep the crawlspace clean by blocking ground moisture from evaporating into the air, which is the primary source of dampness in unsealed crawlspaces. A vapor barrier creates a physical seal in the crawlspace that prevents humidity from entering the crawlspace environment, reducing the risk of condensation, mold growth, and musty odors.
Vapor barriers help to improve crawlspace conditions by keeping insulation dry, preventing wood rot, and making the area less attractive to pests. As well as crawlspace vapor barrier also supports energy efficiency by stabilizing temperature and humidity levels.
6. Seal foundation vents in crawlspace
Sealing foundation vents helps to keep the crawlspace clean by blocking the unfiltered outside air, which often brings in moisture, dust, pests, and mold spores. Unsealed foundation vents allow humid air to enter and condense on cooler crawlspace surfaces, leading to mold, mildew, wood rot, and poor air quality.
To seal the foundation vents, you can use a rigid foam board, caulking, or vent plugs with airtight gaskets to completely close the crawlspace openings. This step works best when combined with other moisture control methods like vapor barriers and dehumidifiers in the crawlspace.
7. Seal crawlspace air leaks
Sealing crawlspace air leaks helps to keep the crawlspace clean by blocking uncontrolled air infiltration that brings in outside humidity, dust, allergens, and pest infestation. Unsealed gaps of the crawlspace around pipes, electrical penetrations, rim joists, vents, and access doors are major entry points for moist air, which leads to condensation, wood rot, and poor indoor air quality.
To seal the crawlspace air leaks, you can use several high-performance materials to seal air leaks, including closed-cell spray foam, urethane caulk, acrylic-based sealants, and foil tape for HVAC and duct penetrations. As well as you can use spray foam insulation in hard-to-reach areas like rim joists and sill plates, where air tends to seep through unnoticed, crawlspace areas.
8. Control crawlspace humidity
Controlling crawlspace humidity helps to keep the crawlspace clean by limiting the presence of excess moisture in the air, which contributes to mold growth, structural wood damage, and pest infestations. The ideal humidity in the crwlspace is between 30%-50% RH. When crawlspace humidity exceeds 70, it creates mold and mildew growth in the area. This makes an unhealthy, musty odor crawlspace with huge structural issues.
To prevent higher humidity in the crawlspace and keep clean you can seal all air leaks, install a continuous vapor barrier, and operate a dedicated crawlspace dehumidifier. As additional humidity controlling methods, you can use a sump pump, French drain system, and crawlspace encapsulation in the area.
9. Insulate crawlspace walls
Insulating crawlspace walls helps to keep the crawlspace clean by reducing heat transfer, controlling moisture buildup, and preventing condensation on surfaces. Unlike fiberglass batts between floor joists, wall insulation creates a thermal envelope that keeps the entire crawlspace environment stable. This method also supports energy efficiency by reducing heating and cooling loss, especially in homes with HVAC systems running through the crawlspace.
To insulate crawlspace walls you can use a rigid foam board (XPS or EPS), closed-cell spray foam, and mineral wool, each offering unique benefits for different climates and budgets.
10. Crawlspace encapsulation
Crawlspace encapsulation helps to keep the crawlspace clean by creating a sealed, controlled environment that blocks moisture, pests, and unfiltered outside air. Crwlspace encapsulation involves covering the crawlspace floor, walls, and piers with a thick polyethylene vapor barrier, typically 12 to 20 mil, and sealing all joints and edges with specialized tape or adhesive.
Once the crawlspace is encapsulated properly, it stays dry, improves indoor air quality, and reduces energy bills by minimizing heat loss. Crwlspace encapsulation also helps prevent condensation on ductwork and plumbing, which protects mechanical systems from corrosion. As well as improperly sealed crawlspace encapsulation system traps moisture instead of blocking it with making more problems in the crawlspace area.
11. Add an airtight access door in crawlspace
Adding an airtight access door helps to keep the crawlspace clean by preventing outside air, moisture, pests, and debris from entering through one of the most common weak points in the crawlspace enclosure. Standard access doors are often thin, loosely fitted, or made of wood that swells and warps, leaving gaps that allow humidity and pests to seep in. An airtight, insulated door seals this entry point and maintains the controlled environment inside the crawlspace, cleaner and tidier.
12. Use pest resistant materials materials in crawlspace
Using pest-resistant materials helps to keep the crawlspace clean by deterring rodents, insects, and termites from nesting, chewing, or damaging structural elements and insulation. Pest and insects contaminate the air quality, damage the vapor barrier, create access paths to the main structure of the house.
To control the pest in the crawlspace you can use borate-treated wood, closed-cell spray foam, and non-cellulose insulation like mineral wool or rigid foam board, which resist insect infestation and decay. For vent and pipe penetrations, you can use stainless steel mesh or copper wool, which rodents can’t chew through. We also recommend installing polyethylene vapor barriers with a thickness of at least 12 mil, which resist tearing and discourage nesting. Replacing standard materials with pest-resistant alternatives significantly reduces the risk of infestation and keeps the crawlspace cleaner, healthier, and easier to maintain over time.
13. Inspect crawlspace twice a year
Inspecting the crawlspace twice a year helps to keep the crawlspace clean by identifying moisture issues, pest activity, and structural concerns before they escalate into major damage to the structure. Crawlspace inspections should be done in spring and fall. Crawlspace inspections allow homeowners or contractors to monitor conditions after heavy rain, temperature changes, or long dry periods that can impact foundation movement and humidity levels.
We recommend a detailed inspection checklist for the crawlspace that includes: checking the vapor barrier for tears, looking for standing water or damp soil, inspecting insulation for sagging or mold, verifying air seal integrity, and checking for signs of rodents, termites, or wood decay for a clean and damage-free area. It’s also important to test crawlspace sump pump systems, dehumidifiers, and drainage lines to ensure they’re operating correctly. In order to keep the crawlspace clean, we highly recommend that you to do a proper and regular inspection as per the above instructions.
