What is Crawl Space Waterproofing?

Article Details
  • Written By: Anna B. Smith
  • Edited By: Michelle Arevalo
  • Last Modified Date: 22 September 2019
  • Copyright Protected:
    Conjecture Corporation
  • Print this Article
Free Widgets for your Site/Blog
There is a railway line in the hills above Budapest, Hungary, that has been operated by children for over 70 years,  more...

October 13 ,  1943 :  In a major turn of events in World War II, Italy declared war on Germany.  more...

Crawl space waterproofing is the process by which the area beneath a home’s foundation is treated with a variety of water-prevention methods to prevent water damage and moisture condensation. It can reduce the likelihood of foundation rot and mold growth over time. This can also help insure the general good condition of the home, and health of its occupants.

Crawl spaces are spaces located beneath the home, that induce air circulation throughout the foundation. They also allow access to piping, duct work, and insulation placed beneath the home. These areas are generally two to three ft (.60 to .91 m) in height, and run the length and width of the structure. Most homes with crawl spaces are built on cinder block foundation framing. These blocks form the exterior walls of the crawl space.

Water build-up in a crawl space area presents a danger due to its high potential for breeding mold and fungi. As air circulates through the crawl spaces and heat rises, the air filtered through the house from the crawl space beneath may be contaminated with mold and fungi spores. These can also begin to penetrate the cinder block and wood framing of the home's structure, and eat away at the framework’s integrity.


A variety of methods are available for crawl space waterproofing, to prevent moisture build-up beneath the home. One of the most common is spreading plastic sheeting around the entire area. This is achieved by placing a polyethylene vapor barrier over the dirt ground surface of the crawl space. The sheeting should overlap by roughly two feet (.60 m) where the pieces meet, and be sealed by duct tape. The sheeting should then reach all exterior walls of the home and be taped into place roughly six inches (15.24 cm) or more above ground level.

Many home improvement companies offer crawl space waterproofing services. These businesses generally install a water barrier that covers the dirt flooring and exterior walls of the crawl space. Several also recommend closing open ventilation windows to prevent the introduction of humid air from outside the home. Once this is closed, conditioned air may be pumped into the crawl space to maintain a dry environment. Generally, home improvement companies will complete the waterproofing process by spraying foam insulation into any areas of the home’s flooring that allow air leakage between the two areas.

Sump pumps are also used in the waterproofing of crawl spaces. A sump pump is a machine that manually pumps water away from an area. These are valuable in homes where the natural grade of the land beneath the foundation does not allow for adequate drainage of water. These pumps may be installed manually or by professional contractors.

To prevent water from leaking in and compromising the crawl space waterproofing methods used, property owners may benefit from redirecting gutter down spouts away from the home. A down spout should be directed roughly eight to ten feet (2.43 to 3.04 m) away from the home. These should also be cleaned regularly to prevent water build-up due to leaf and silt congestion.


You might also Like


Discuss this Article

Post your comments

Post Anonymously


forgot password?