top of page

Interior Waterproofing for Crawlspaces

De-Watering is exactly what the name implies—getting rid of water. It should not be confused with waterproofing even though most waterproofing companies offer de-watering systems. Typically, when we de-water a crawlspace, we install a drainage system, usually some type of french drain around the perimeter. Water is intercepted with the system before it has a chance to create puddles on the crawlspace floor. There are two methods of getting rid of the water that the perimeter drainage system has collected—installing a gravity drain or installing a pump system. A gravity drain is a downhill pipe sloped away from the house. It’s often referred to as a ‘tail line’. A gravity drain is the preferred method but there must be a destination for this pipe, or pipes, well below the deepest level of the crawlspace to which the water can flow. If there is no such destination on the property, the second method of water disposal is unavoidable—a pump system must then be used. Sometimes a pump system is opted for because it costs less and is easier to install. 


De-Watering is rarely the method of choice during home construction—it’s more likely to be employed for not-so-new houses with established landscaping, connected utilities, air conditioners, patios, decks, additions, garages, etc. We refer to these situations as ‘retrofit’ installations. 


Over 95% of our business is ‘retrofit’ (going back and re-doing original systems that failed). Over half of these failed systems are less than 10 years old; 30% are less than 3 years old, and many are brand new. Almost all of the failed systems that we replace were originally installed in complete compliance with local building codes, and all passed inspection.


For more information and help determining if Interior De-Watering is best for your crawlspace, please contact us to schedule a FREE inspection and consultation.



Why worry about water in your Crawlspace?

Unlike the people who have wet basement problems, many folks with wet crawlspaces are unaware of the problem—or don’t think it’s a bad problem. The symptoms of a wet crawlspace certainly aren’t as readily apparent as with a flooding basement but the consequences can actually be worse. Deterioration of the substructure of a house can cost a homeowner much more than ruined furniture or carpet—and most insurance doesn’t cover the deterioration because it’s considered a (lack of) maintenance issue. Heavy moisture, standing water, and/or running water in a crawlspace can cause many structural problems. They can also invite a build up of mold, mildew and fungus on sub-flooring, insulation, and on the contents of a crawlspace. Not only can mold lead to wood-rot and costly repairs, it can be very detrimental to your health. Lindsley Waterproofing addresses all of those problems.


The most common BAD ADVICE: "Your crawlspace will be dry if you fix your gutters, extend buried pipes for your downspouts, and grade the surface to slope away from the house.” Not really bad advice to do those things as long as it’s pointed out that those improvements won’t cure a wet crawlspace problem. Only when it’s suggested that doing the above will solve a water problem is it truly misleading advice. A false sense of security can have disastrous results. Without question every drop of water that’s diverted away from a house is a good thing. The above steps are definite improvements. We do them all the time. Just don’t expect those steps to completely solve a water intrusion problem. Simple logic explains why it’s just not enough:


  1. If a crawlspace is getting wet, that automatically means that the in-ground protection is failing. That would be a Waterproofing and/or a Drainage failure

  2. Therefore, when the ground gets saturated, the failure(s) will be exploited.

  3. NO AMOUNT OF GRADING WILL STOP THE GROUND FROM GETTING SATURATED. (If a sloped surface kept water out of the ground, there would be no trees, or any other vegetation on the sides of hills or mountains.)


The 2nd most common BAD ADVICE: “Your crawlspace has a positive drain to let water out so it doesn’t matter if water is getting in.” You might as well say that it’s ok to be bleeding as long as you have a rag to wipe off the blood. Positive drains are outlet pipes at the lowest corner of a crawlspace and are now required for new homes. They prevent catastrophic flooding in the event that water somehow gets into a crawlspace. For example, if a pipe or a water heater breaks, furnaces or other appliances could be ruined if there is not a means to let water out of a crawlspace. The positive drain limits the depth of the standing water resulting from the mishap. A positive drain is similar to an air bag—it’s nice that it’s there but let’s hope that it’s never needed. The presence of a positive drain absolutely does not mean that it’s ok for rainwater to routinely invade a crawlspace. By the time that ground water (which usually enters a crawlspace from the upper sides) finally makes its way to the lower corner and then out the Positive drain it has already done its damage. The ground is wet, there is erosion, there are puddles, and/or the humidity is excessive.


The 3rd most common BAD ADVICE: “You don’t have any standing water in your crawlspace—it’s only wet—so there’s no real problem.” It’s a little known fact that more moisture gets into the air from a square foot of wet soil surface than from a square foot of standing water. The square foot of standing water has exactly 1 square foot of water in contact with the air. A square foot of wet dirt has much more water than that in contact with the air—the soil acts just like a wick. The amount of water in contact with the air determines how quickly evaporation takes place and subsequently how humid a crawlspace can get.


For more information and help determining if Interior De-Watering is best for your crawlspace, please contact us to schedule a FREE inspection and consultation.



Since 1994 Lindsley Waterproofing has been Making Homes Healthy by providing expert waterproofing services to homes and businesses in the Research Triangle region of North Carolina. We can help you if you are in or are near Apex, Benson, Carrboro, Cary, Chapel Hill, Clayton, Durham, Franklinton, Fuquay Varina, Garner, Hillsborough, Holly Springs, Knightdale, Pittsboro, Raleigh, Rolesville, Roxboro, Selma, Smithfield, Wake Forest, Wendell, Youngsville, Zebulon, North Carolina. We repair and prevent structural water damage provide for new & existing structures. Our guaranteed services include de-watering, foundation repair, structural repair, fixing foundation leaks, waterproofing, yard drainage, french drains, crawlspace conditioning, helical pier foundations and ensuring that we help you to create a healthy home.

bottom of page