Should You Fill Cracks In A Basement Floor?

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It’s important to keep a basement floor well-maintained. Part of this includes periodically checking the floor for cracks, leaks, and other signs of damage. But should you fill the cracks in the basement floor? And if so, how? We have researched the answer to these questions, and in this post, we will cover them.

The best practices for maintaining a basement floor include giving it a good sweeping as often as needed to keep debris and dust levels down. You also want to check the floor drain periodically to ensure that it is not clogged or emitting any foul odors, as this can be a sign of plumbing issues that may eventually affect other areas of your home. While basement floors are prone to cracks, if you notice any cracks that seem to be spreading or are larger than 1/8 of an inch in width, you may want to do a bit of investigating and then repair the crack–especially if the crack is over 6 inches long.

Sometimes cracks can be just a normal part of a home settling on his foundation. Other times, basement floor cracks can be a tell-tale sign that issues should be addressed within the basement’s structure. Continue reading to learn more about basement cracks and how to repair them.

Inside view of sub-basement with stairs, Should You Fill Cracks In A Basement Floor?

Understanding Basement Floor Cracks

For the most part, you’ll find that cracks in your basement floor are normal and generally aren’t much to worry about. However, there may come a time when you should be concerned with the cracks. This is usually if the cracks start to change size, shape, or form and they’re in different floor areas where they hadn’t been previously.

There are a few things to watch out for that may indicate serious issues within your basement. They include the following:

  • Drywall cracks
  • Sloping floors
  • Suddenly misaligned windows and doors
  • Bowing walls
  • Ceramic tile cracks
  • Drywall cracks

Monitoring the cracks

Foundation cracks can pose a hazardous condition to the basement and the rest of your home. Monitoring the cracks is the best way to avoid these conditions as well as expensive repairs. To do this, you can take a tape measure and measure the length and width of the crack.

Do this every 2 to 4 weeks to see if the crack is getting bigger. If you notice that the crack has increased half an inch, then it’s time to contact a contractor. Also, pay attention to the position of the crack.

Horizontal cracks that appear against the wall can be a sign of a structural breakdown within the basement. These are usually caused by pressure beneath the soil pushing the wall forward, causing it to slightly bend. This could be due to wind pressure, corroded wall ties, or the home simply being old. Finding the root cause of these types of cracks is essential to preventing a structural collapse.

Is it normal for a basement floor to crack?

Yes, if the basement floor is made of concrete, then cracking is a natural occurrence. As the concrete dries and becomes a slab, it shrinks during the process. When it shrinks, it will start to form small hairline cracks that won’t affect the integrity of the slab. The size and the amount of these cracks will depend on the quality of work provided by the contractors who installed the slab and the quality of the concrete mix used for the job. Other cracks can show up in the basement outside of normal shrinkage cracks. Let’s take a look at them.

Settling floor cracks

These cracks occur when the soil beneath the floor pushes upwards due to expansion, such as heavy snowfall or rainfall. Once the ground begins to dry, the soil will settle back again. However, the concrete will crack, as it cannot bend to accommodate the soil, resulting in the often seen cracks in basement floors, driveways, and sidewalks.

In severe cases, the entire floor may need to be re-poured. However, it’s best to have a professional foundation contractor come to look at the cracks to see if they should be addressed.

Premature drying floor cracks

Sometimes certain areas of the floor may dry faster than others after the concrete is poured. This can cause small hairline cracks to form around the floor. Though they may appear unsightly, they typically aren’t anything that can cause structural issues for the home. In many cases, you can simply fill them with epoxy.

Expansion floor cracks

Expansion floor cracks occur when the floor expands and contracts due to high temperatures or when a concrete mix is made with too much water. The concrete will expand, but it can’t flex or bend. As a result, it has no choice but to crack against the surrounding walls or other hard surfaces in the basement. You usually find these types of cracks close to wall joists and corners. These cracks are also common and can be fixed by re-pouring the concrete or filling the holes with epoxy.

When should I be concerned about cracks in my basement floor?

You should be concerned about cracks in your basement floor if the cracks are larger than an eighth of an inch wide. Cracks like these can lead to issues with pests, water damage, and potential structural hazards. You also want to pay special attention to cracks that may seem to get worse fairly quickly. Typically, if the crack doubles in size within a month, you should call a contractor to have them do an assessment.

While it’s normal to have cracks in concrete basement floors, the appearance of large sudden cracks can indicate serious structural issues or foundational issues caused by the soil beneath the concrete.

How do you fix a cracked basement floor?

The best way to fix a cracked basement floor is to fill the affected areas with an epoxy crack formula. There are several different brands available to do this, some of which we will discuss later. Let’s look at how to do it.

Things you’ll need:

  • Angle sander
  • Masonry trowel
  • Hairline crack repair
  • Epoxy formula
  • Masonry wire brush
  • Screwdriver

1. Clean out the crack

For this step, take your wire brush and scrub inside and around the crack to help loosen any dirt and debris that may be inside of it. You can also use a shop vacuum to do this as well. It’s important to make sure the crack is empty to avoid having the dirt push the epoxy up when the soil beneath the floor becomes moist.

Check out this shop-vac on Amazon.

2. Fill the crack with epoxy

Next, take the epoxy solution and mix it if it’s a two-part formula. If not, use your masonry trowel to push the epoxy into the crack. Use several applications to push the epoxy as deep into the crack as possible and then smooth out the top layer of the crack. Let the epoxy cure for the recommended time before going to the next step. This will typically be anywhere from 8 to 12 hours, but always check the directions on the package.

3. Sand the epoxy

After the epoxy has cured, take an angle sander and carefully go over the surface to smooth out the epoxy. You’ll want to get the area as flat as possible to avoid a walking/tripping hazard.

Read more details about this angle sander on Amazon.

What do you fill basement floor cracks with?

Here are a few highly recommended solutions that you can use to fill cracks in your basement floor.

3-Part Epoxy Mortar Patching System

This 3-part epoxy solution is great for concrete, wood, metal, and asphalt. It’s surprisingly 10 times stronger than typical cement, and it’s capable of forming a solid bond to almost any service. You’ll be happy to learn that this solution is waterproof and weatherproof.

Read more about this formula on Amazon.

PC Products 72561 PC-Concrete Two-Part Epoxy Adhesive Paste

Here is a two-part epoxy pay system that is great for filling both small and large cracks. This solution cures in about four hours and will outperform any hydraulic cement or caulk when it comes to durability. This is a high-tack paste formula that is moisture-resistant, so you don’t have to worry about your basement being too humid for it to set properly. You can also use the solution on unreinforced masonry as well as grout-filled blocks.

Learn more details on this formula on Amazon.

Wrapping Things Up

As you can see, there are a few things to consider when it comes to deciding whether or not to fill a crack in your basement’s floor. The major takeaway here is to monitor any large or fast-growing cracks frequently and to call a foundational contractor if you believe that the crack can pose a serious hazard to your home.

Before you go, be sure to check out some of our other posts:

Should You Store Firewood In Your Garage?

Should Floor And Wall Grout Match?

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