September 27

Basement Waterproofing FAQs


We are asked many questions as it relates to basement waterproofing, and understandably so given the amount of factors that must be taken into consideration.  Listed below are some of the questions we get asked the most, and a little insight into each one from our basement waterproofing experts.

What is the Average Cost of Basement Waterproofing?

There is not necessarily an “average” cost of basement waterproofing due to a multitude of factors that come into play when waterproofing a basement.  A couple of these factors include labor, severity of damage, materials etc. While there isn’t necessarily an average cost of basement waterproofing,if you are a homeowner in Raleigh, you can expect to pay anywhere between $3000-$5000 for a 1200 square foot basement.

Why Do I Need to Waterproof My Basement?

The most important reason for waterproofing your basement is maintaining the structural integrity of your home to combat some of the harsh weather conditions we have come to expect in Raleigh.  When the structural integrity of a home has been compromised, the living conditions can become overwhelming, having to deal from everything to leaking to damp walls and even potential flooding. The irreparable damage caused will almost certainly be more expensive than taking the initial step of waterproofing your basement.  Vapor barrier installation and other waterproofing services can help save your home from more severe damage.

What are the Benefits of Waterproofing My Basement?

Reduction in Costs of Insurance Claims

Believe it or not, approximately one fifth of all insurance claims made by homeowners are related to water damage.  Everything from slow, small leaks to major storms and flooding can lead to significant structural damage, so making the initial investment to waterproof your basement can save you money in the long run.

Prevention of Structural Damage

Significant structural damage may occur due to water seepage through the foundation of your home, particularly the joints and edges where the flooring and walls meet.  The structural damage may include foundation cracks and buckling of the walls and flooring that can eventually threaten the structural integrity of your house. Waterproofing is an effective measure that will 

Healthy Environment in your Home

Mold or mildew can manifest if excess water or high moisture levels exist in your household.  Beyond the damage mold or mildew can inflict on your property, negative health effects including allergies, breathing issues, and respiratory infections may arise.  While mold remediation can take care of the problem, waterproofing your basement helps prevent mold growth in the first place by minimizing the moisture.  

When is the Best Time to Have my Basement Waterproofed?

Ideally, you want to plan to avoid two kinds of weather: rain and cold winter weather.  Luckily here in Raleigh, we tend to have pretty hot, sunny summers (that sometimes extend to the fall), so you should have ample time to plan accordingly.  

How Rainfall Impacts Waterproofing

Rainfall is incredibly disruptive when waterproofing, particularly during the excavation process.  Wet clay is almost always impossible to work in as it can come close to resembling working in quick sand, you may just end up sinking!  The same can be said for sandy and clay soils, which are particularly susceptible to caving in when rain is present.  

How Cold Weather Impacts Waterproofing

Cold weather, particularly freezing winter cold weather, can be extremely harmful to your home’s structural integrity.  Coating a foundation during the winter must be done with a solvent based product, NOT a water based product. Water based coatings are much more prone to issues with freezing, and if your foundation is exposed to freezing temperatures for several days, the foundation could heave from frost and become very damaged as a result.  Freeze and thaw cycles also increase the likelihood of cave-ins which are extremely dangerous under these conditions, and could require additional excavation.

How Do I Waterproof a Basement on the Outside?

Waterproofing from the exterior can be beneficial for one relatively obvious reason: outside is where the water is.  This water will eventually enter the basement via the soil that surrounds it, either below the foundation or around it.

Installing an exterior waterproofing membrane is the best route to take when waterproofing a basement outside.  An exterior waterproofing membrane creates an impermeable water barrier on the outside of the foundation. Installing an exterior waterproofing membrane is an extremely labor intensive process and requires a huge amount of time, so we recommend reaching out to one of our experts to get the job done.

How Do I Waterproof a Basement on the Inside?

While interior waterproofing of a basement is indeed possible, we recommend exterior waterproofing, as it is the surest way to waterproof your basement walls.  However, if this is outside your budget, there are a few ways you can go about waterproofing your basement from the inside.

Concrete Waterproofing Coatings

These thick coatings are as the name implies, cement-like.  Once dry, they adhere permanently to concrete and masonry walls.  Concrete waterproof coatings cannot be applied to previously painted surfaces, so make sure to check the label when purchasing.

Silicate-Based Concrete Sealers

Also known as densifiers, are also suitable only for walls that haven’t been painted or sealed.  The sealers soak in and chemically react with ingredients in the concrete or brick, forming a hard, waterproof surface.  Due to the fact these are penetrating sealers, they can’t flake off or peel, and you can paint over them, as opposed to the concrete waterproofing coating.

Waterproofing Paint

Waterproofing paint is an acrylic formula, not much different from regular wall paint.  The key difference is you apply the paint a lot thicker than you would a typical wall paint.  One gallon covers 75 sq ft, as opposed to the typical 300 sq ft regular wall paint covers.  

Plastic Sheets and Panels

Plastic sheets and panels are suitable as wall waterproofing only in combination with interior basement drainage systems.  While they don’t totally prevent water from getting through the wall, they can stop water from ruining things.  

What Causes Cracks on my Basement Walls?

There are two kinds of cracks to keep an eye out for: horizontal and vertical cracks.  Both are troublesome and must be attended to as soon as possible.

Vertical and Diagonal Cracks

Vertical cracks and diagonal cracks are typically the result of settling in the concrete foundation and is quite common in new construction.  These cracks usually run vertically or diagonally, and are often located in the middle section of walls and are less than ⅛ inches wide.

You will also find vertical cracks in block foundations.  If you notice cracks located closer to a corner and wider than the typical ⅛ inch, it may be indicative of a more serious issue. 

Horizontal Cracks

Horizontal cracks typically indicate a more serious issue.  They are caused by water pressure from the outside of the walls and can lead to a failure in the foundation.  Additional pressure to foundations due to heavy rains or flooding can create serious horizontal cracks that need to be repaired as soon as possible.  It is extremely important to contact one of our specialists immediately if you see these cracks in your basement’s foundation.  

Contact CBT of NC for Basement and Crawlspace Waterproofing in Raleigh

If you experience a leak or a flood in your home, we’re here to help. At Crawl Space & Basement Technologies, we offer crawlspace and basement waterproofing so if there are leaks, cracks or anything else, the structure of your home will stay safe and secure. Call us at 919-847-7072 or complete our online contact form to learn more about our services!


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