How Bad Is Moisture in a Crawl Space?

Many families have crawl spaces, and many friends like houses with crawl spaces under the first floor because crawl spaces greatly expand our living space. But most crawl spaces will face serious problems: moisture, leakage, and mold.

 

Bad Influence of a Damp Crawl Space

1. Hazards to building structures

Wall cracking and foundation subsidence

Moisture can cause concrete and masonry materials to absorb water, expand, or corrode, leading to structural cracks, wall peeling, and even unstable foundations over time.

Wood structure rots

If there are wooden floors or supporting structures in the crawl space, it will rot and lose its load-bearing capacity in a long-term humid environment, posing a serious safety hazard.

Mold spots and the salt precipitation phenomenon

Moisture causes the wall to "sweat", forming a white powdery substance (salt precipitation), which damages the coating and decoration materials.

2. Hazards to health

Mold growth

Moisture is the ideal breeding environment for fungi, and the presence of fungal spores in the air can cause problems such as asthma, rhinitis, skin diseases, and allergic reactions.

The air quality has deteriorated

The humid environment is stuffy and heavy, with reduced oxygen content and even accompanied by moldy and unpleasant odors. Living in such an environment for a long time can easily lead to fatigue, headaches, and weakened immunity.

Inducing dust mite reproduction

Dust mites prefer humid environments and are a common cause of allergic rhinitis and skin itching.

3. Damage to family property

Electrical equipment is damaged by moisture

The crawl space is commonly used for storing electrical appliances or as a computer room, and moisture may cause problems such as short circuits in wires, rusting of equipment, and data loss.

Furniture decay and mold

Wooden furniture, cardboard boxes, clothing, etc., are prone to deformation and mold growth in humid environments, resulting in property damage or even irreparable damage.

Deformation of the carpet floor

Carpets are prone to mold and odor after absorbing moisture, while wooden floors warp and crack after absorbing water and expanding.

 

Why is the crawl space damp?

1. Large temperature difference between inside and outside, prone to condensation

The temperature in most crawl spaces is lower than the normal room temperature, and condensation occurs when external air enters the cooler crawl spaces. The external air entering the cold crawl space will cause water vapor to condense, especially in humid weather, where the resurgence of moisture in the crawl space will be more pronounced.

2. Poor lighting and ventilation

Most crawl spaces have poor ventilation and lack light, resulting in poor air circulation and an inability to expel moisture, leading to an increase in crawl space humidity.

3. External water seepage

Rooms with crawl spaces need to be waterproofed to prevent external domestic water and rainwater from leaking into the room, causing moisture in the crawl space. Or uneven settlement of the house can cause cracks in the waterproof structure of the crawl space, leading to water seepage and moisture regain in the crawl space.

 

How to deal with a damp crawl space?

1. Waterproofing

Waterproofing is usually done before decoration, especially for villas. After civil construction, the crawl space needs to be waterproofed once, including waterproofing of the exterior walls. At the same time, it is necessary to check for water seepage during the rainy season and promptly address any issues found.

2. Ventilation and moisture prevention

Due to its location, the air circulation in the crawl space is already poor, so it is advisable to consider providing more ventilation in the crawl space. Installing exhaust fans, fresh air systems, and other methods can increase air circulation in the crawl space and reduce the accumulation of moisture. Especially during the rainy season in the south, a fresh air system can be installed to prevent indoor humidity from being exacerbated by opening windows.

3. Floor heating

Northern underfloor heating is a necessary heating facility in winter, and rooms using underfloor heating are usually relatively dry. Therefore, underfloor heating can be installed in the north during winter to prevent crawl space moisture from returning.

The use of gas wall-mounted boilers and ventilation can also accelerate the evaporation and discharge of accumulated water in the crawl space, making it dry.

4. Dehumidifier

Using dehumidifiers is a good method of dehumidification, which can be combined with air conditioning or underfloor heating to accelerate the dehumidification speed. There is a kind of under home dehumidifier that is ceiling mounted to save space. It can be connected to the HVAC system to control humidity and improve the efficiency of other appliances (eg, AC, heater). Preair is a professional home dehumidifier manufacturer. Contact us if you need bulk crawl space dehumidifiers.

5. Desiccant

If the crawl space is not particularly humid, some desiccants, activated carbon, etc. can also be used for dehumidification treatment, but only for spaces such as cabinets and drawers, and cannot dehumidify the entire room.