I Discovered Water in My Basement: What Now

The discovery of a wet basement calls for more than headache medication. What can appear to be a small puddle or tiny trickle can turn into a much bigger issue for homeowners.

Moisture that accumulates in your home’s basement causes expensive, time-consuming problems and likely damage.

With problems ranging from structural damage to toxic mold, that” little leak” needs to be addressed immediately.

Humid, damp, and wet basements result in peeling paint, extreme mildew growth, and damage to any stored items. This article will fill you in on basement waterproofing’s hows and whys and give several “insider tips and tricks” on doing it right the first time.

What Is Basement Waterproofing

Basement waterproofing has the goal of preventing water from entering the basement of a home or building. Waterproofing a basement below ground level is no simple task and will require sealant materials, drains, sump pumps, and more.

There are two general methods to waterproof a basement; sealing the exterior, and sealing the interior. You do not need to perform both types of basement waterproofing to be effective in your sealing efforts.

House basement walls covered with black parge coating for exterior waterproofing

What Causes Flooding or Leaking in the Basement

The biggest reason a basement may flood is from improper drainage and soil systems surrounding the home’s foundation. This means the rain and groundwater cannot effectively drain away from the home’s exterior and will begin accumulating around the foundation.

Poorly installed and maintained gutters only add to this problem. If your gutters aren’t installed correctly or are too clogged, water will drain directly to the foundation rather than away from it.

Another cause of water in the basement could be an improper slope of the grade around the home. When built below grade, basements tend towards moisture problems more easily.

The ground surrounding your home is supposed to slope away from the foundation at a rate of 6 inches vertically for the first ten feet horizontally. An insufficient slope can guide water towards the home rather than away from it.

Hydrostatic pressure can also cause basement flooding. Hydrostatic pressure occurs when water collects around the home’s foundation and builds up pressure.

Once built up, this increased pressure forces water through any floor or wall cracks. This can cause more and more damage to the foundation walls. The hydrostatic pressure forces can become so strong as to generate more cracks to form, even in cement basement walls.

The last cause of dampness could be cracks in the basement walls or slab.

Although the home is not built with cracks, they tend to form over time due to shifting in the foundation typically caused by differential settlement of the house and other mechanical forces acting on the foundation.

When the soil outside becomes saturated, water can seep through the cracks in the walls. Even sound basement walls can absorb moisture from the soggy ground, making the walls appear wet.

When this water evaporates, it will evaporate inside the home, increasing relative humidity and leave dried mineral deposits on the basement walls, known as efflorescence.

A humidifier could solve the condensation issue short-term, but you will need to waterproof the basement walls for any long-term solutions.

When to Waterproof Your Basement

Because of the texture of concrete walls, you can often see wet streaks where the water is coming in. Check for streaks along any cracks, corners of windows, or around pipes. If entire wall surfaces are wet, you may need to do a condensation test.

A simple but easy way to begin figuring out the extent of the issue is with a 1-foot square piece of aluminum foil. You take the piece and tape it to the inside of your basement walls for 24 hours. After 24 hours, if there is condensation on the outside of the foil but not the inside, you have high humidity in the room itself.

High relative humidity in the basement can easily be fixed with a whole-house dehumidifier system or a smaller single room dehumidifier.

If the foil has condensation on the inside surface (the side facing the wall), this indicates moisture may be intruding from the soil around your house. In this case, waterproofing the walls in your basement would be the ideal option.

Here are the Top Basement Waterproofing Methods

Interior fixes are the most helpful in cases where the water leakage is minimal. If there are signs of fine cracks that seep slowly or look wet, then a quality interior sealant could help.

The majority of heavy-duty interior masonry sealants only work on unpainted walls, so ensure to check beforehand that the application surface is unpainted.

Available in various sizes from one and five-gallon buckets. The sealants require heavy-duty brushes or rollers, and the cost ranges from $50-$500, depending on the size of the area needing cover.

Cracks are often found at the bottom of the basement walls, where the concrete floor meets the wall. When a foundation is built, the base is poured first, and then the walls are poured after that hardens.

Although this is a standard procedure, it can create something known as a “cold joint” or a weak spot where the floor and the wall meet. This weak spot can result in cracks and crevices, allowing for unwanted water penetration into your basement.

Fortunately, sealing cracks and gaps is an easy DIY fix. Just filling them with hydraulic cement helps immensely. Hydraulic cement contains additives that cause the cement to expand and set rapidly, making it perfect for plugging leaks.


Hydraulic cement is then mixed with water to create a heavy, putty consistency before pressing the cement into the cracks with gloved fingers or a putty knife.

As it expands, it pushes deep into the crevices and forms a watertight bond. One tip to remember is that hydraulic cement sets in three minutes, so be careful when determining the amount to mix.

You can also seal the walls using high-quality waterproof paint. It comes premixed and rolls on the same as a coat of paint. Brush or roll the paint on thickly enough to fill all the small holes and dry before painting the second coat. A five-gallon container treats about 500 square feet of wall space.

If there are still cracks or if the previous attempt to seal the cracks fails, you may have to install an interior floor drainage system.

Like the exterior one, a drain system is installed inside the basement to guide the water to a designated area. If you are handy, have a strong back, and can get your hands on a concrete saw and jackhammer, then you can potentially install a basement drainage system yourself.

This process is similar to installing exterior drain tile, but the excavation is very confined and shallow.

First, excavate a trench along the perimeter of the basement. A sump pit for the water collection needs to be established, and the channel needs to be filled with pea gravel and perforated drain tile.

Lastly, fill the trench with concrete so that a narrow grate is the only visible part remaining visible. Normally, plastic panels are also installed over the leaky areas to guide them to the drain. Installation of all these items can run up into the thousands of dollars, but doing it yourself can save quite a bit of money.

7 Secrets To The Most Successful Basement Waterproofing Job -

The most effective way to avoid water in the basement is from the exterior, but this is also the most complicated. You may even need a permit before starting, and some states may only allow a licensed contractor to perform this work.

Typically, an external drainage system is already installed around the home if you purchased an existing structure.

Creating an external drainage system consists of excavating soil around the exterior of the home and installing a drain tile at the foundation’s base.

A drain tile is a flexible, perforated pipe covered with mesh. The drain tile also requires a sump pit where the water will collect before it’s pumped to the surface. A sump pump will also need to be installed to pump the water out from the sump pit.

Hiring a certified contractor may be necessary because of the risks of digging a seven or 8-foot deep trench around the home. When planning for the project, ensure dry weather to avoid having to pump water out of the newly-dug trench before you can complete any work.

Simultaneously, as the drain tile is installed, make any needed repairs to the rest of your home’s exterior. Large cracks can be patched with a mortar-based product and then finished with a mortar-based sealant.

The total estimate for an exterior waterproofing job is about $10,000, but it is the surest way to waterproof.

If you don’t have the funds for this project yet, don’t panic! There are a couple of other tips and tricks that can help protect your foundation from water.

One easy project is to install gutters and downspouts if you do not already have them. Then, attach downspout extensions that direct the rainwater away from the home’s foundation.

Your yard should slope away from the foundation at a rate of six inches over the first ten feet, and if it doesn’t, the addition of topsoil around the base of the home could help alleviate some issues.

If so, bring in the topsoil to build up the soil around the foundation. Simply relocating any plants or foliage near the foundation that needs to be watered regularly to another area will help.

Another tip is to install waterproof window well covers on any basement windows that need them.

Wrapping It Up

Water pooling by the foundation of the home is always bad. If you can keep the water away from your home’s foundation, you have a much better chance of keeping your basement safe and dry.

Whether it be a basement drainage system or a new paint job, there are many ways to keep moisture intrusion from happening to you. By following the tips and tricks included in this article, your basement is sure to become the space you’ve been wanting.

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