How to Get Rid of Moisture Under a House?

Here is a direct breakdown of why moisture collects under a house and how to fix each cause:

 

Common Reasons for Dampness in Crawl Space:

Poor Drainage Around the Foundation

Water from rain or irrigation runs toward the house and pools near or under it.

Fix:

Re-grade the soil so it slopes away from the house.

Install gutters and downspouts that direct water away (at least 4–6 feet).

Add a French drain if needed.

 

No or Poor Vapor Barrier

Moisture from the soil evaporates into the crawl space.

Fix:

Install a plastic vapor barrier (6–20 mil thick) across the crawl space floor.

Tape seams and seal the edges up the walls.

 

High Humidity and Poor Ventilation

Trapped humid air cannot escape and condenses under the house.

Fix:

Open or add ventilation grilles in the crawl space.

Install a dehumidifier for under house if natural airflow isn't enough. The cost of dehumidifier is reasonable. Do not hesitate.

 

Leaking Pipes or HVAC Condensation

Water from plumbing or AC lines leaks into the crawl space.

Fix:

Inspect for leaking water lines and condensation on ductwork.

Wrap pipes or repair leaks as needed.

 

Cracks in the Foundation or Walls

Water enters directly through structural gaps.

Fix:

Seal cracks with hydraulic cement or waterproofing sealant.

Consider professional foundation repair for large cracks.

 

Standing Water After Rain

Indicates water intrusion or groundwater seepage.

Fix:

Use a sump pump to remove standing water.

Combine with drainage and vapor barrier solutions for long-term protection.

 

Recommanded Crawl Space Dehumidifiers

From the professional perspective of a dehumidifier manufacturer, PREAIR suggests the main parameters to consider before purchasing a dehumidifier, which are capacities, control methods, installation, and warranty. A precondition that I suggest you choose the PREAIR dehumidifier is its affordable price. The 70 PPD and 103 PPD can cover almost all the requirements of ordinary houses and other similar spaces. The choice of capacity and the number of dehumidifiers need to be calculated. Four methods of control are designed for our customers. Have a try and choose the most suitable one. When talking about the installation, users must ask professional workers for help because many details and precautions should be considered carefully. Therefore, there is a popular self-installation warning. If the dehumidifier fails after customers install it by themselves, the manufacturer will provide some suggestions for fixing it, but takes no responsibility. Bookmark our website. More and more information about dehumidifiers will be provided for you.