Gap Between Basement Wall And Floor – Why, And What To Do?

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Not all homes have a basement. But what if you're lucky enough to have it, and later you discover that a gap is sitting on the edge between the basement wall and the floor? Relax, we're here to take your worries away! We profoundly studied it, and we'll share with you what we found.

In the best case scenario, you can seal the gap yourself. Examine how the gap formed and then seal it with a concrete mixture that blends with the foundation. However, you might require the services of a professional contractor for a long-term solution depending on the initial cause.

We have so much more to tell you on this topic! Aside from sealing this gap, there are other safety measures to consider when you discover it between the wall and floor. Read through the post and you'll know what's best for your basement.

A rays of sunlight shining through the window hitting the wall on basement, Gap Between Basement Wall And Floor - Why, And What To Do?

Causes of the Gap Between Basement Wall & Floor

There's a lot of possibilities on why a gap appeared between the basement wall and its floor. Listed below are some of these potential factors:

  • Inaccurate measurement of the foundation
  • Incorrect way of pouring the concrete mixture
  • Damaged water pipes
  • Hydraulic pressure
  • Soil corrosion or earthquake
  • Sinking floor

Water leak in a parking lot wall

You need professional help to fix some of these problems. However, we also included a list of possible long-term solutions. See the list below:

  • Installation of a drainage system
  • Repair of damaged water pipes
  • Wall alignment
  • Complete reconstruction of the foundation

Lining sewage with plastic pipes, drainage of waste water from the house

As a homeowner, you should be aware of the previous construction made to your home. It will help experts to point out the main fault when a gap develops.

How to Fix the Gap Between Basement Wall & Floor

Depending on the extremity of the gap, other repair options or even problems can arise. So, an assessment should be done first.

Applying A Concrete Mixture To The Basement Wall Gap

Hand with a trowel in a bucket with plaster

After the assessment, you can now proceed with the sealing technique. Here are the steps you can follow:

  1. Clean the whole area. Measure the gap to estimate the area you need to cover.
  2. Make a concrete mixture. It's usually composed of sand, water, small rocks, and gravel.
  3. Apply the concrete mixture to the damaged spot.
  4. Flatten the wet concrete both on the floor and the wall.
  5. Cover the spot with a plastic sheet or wood to block moisture and make it dry faster. You may add a sealant to secure the edges.
  6. Upon drying, paint the foundation to blend with the color.
  7. Observe the output for several days or weeks. More specifically, until it rains.
  8. Consult an expert if it starts leaking and the seal on the gap does not work.

Sealing the gap is can be either a temporary or permanent cure depending on if another problem pops up. But, at least, it can buy you some time to prepare for some long-term solutions.

Covering The Basement Wall Gap With A Sealant

Sealants may be the fastest tool to fill the basement gap. Unlike the concrete solution, a sealant is advisable for narrow gaps. You need to review the materials used in construction to easily identify what sealant will be best to use. 

Bonding waterproofing tape to the floor

Here's how you can do it:

  1. Measure the height and length of the gap. The amount of sealant will depend on it.
  2. Apply the sealant based on its instructions.
  3. If the gap is too large for the sealant to fill, you could try applying a concrete mixture first. You'll save a lot of sealant this way.
  4. Finish by painting the spot.

If these two primary suggestions do not appear to be effective for your basement, it is time to consult an expert. Explain everything to them, including what you did to close the gap. This will lessen uncertainties about the cause.

Can Paint Seal The Basement Wall Gap?

The gap must be narrow for the paint to cover. It's obviously useless if the gap is wide. But the efficiency of sealing depends on the type of paint. Some of the paint options are waterproof, electrical, adhesive, and latex. Before applying paint to the gap, review its properties.

Wall painter tool for work

Is A Basement Wall Gap Dangerous? [And How To Assess It]

It's okay to be concerned about the basement gap because it's created below ground. Peek through the hole to see what's on the other side. If you come across soil, determine whether it is dry or wet. By soil, we mean the Earth's actual layer or dirt.

Dry soil is acceptable because it can be hardened with cement or be sealed like what we discussed above. A wet soil, on the other hand, is suspicious. You can't just skip over it without doing a further evaluation. 

Flooding rainwater or floor heating systems, causing damage, peeling paint and mildew

So, what if you see wet soil behind the gap in your basement wall? Refer to these assessment tips:

  • Do not panic. What we need to figure out is what made it wet. Is it the rain? The climate? Or the water pipes?
  • Is there any wet part of our house that is supposedly dry? Try surveying the walls if there's liquid penetrating through them.
  • Is the soil odorous? It's critical if the odor is unusual, such as gasoline, chemicals, or decay.

Re-evaluate the gap. If, on the other hand, there is no visible soil through the gap, you can now sound test the foundation. From behind, a solid wall sounds like a large, nearly silent rock. A hollow wall from behind sounds like a Tupperware with an audible air leak. A low hum might also be heard coming from behind the wall, which possibly means that water is flowing.

You can also use a flashlight to determine the depth of the gap. Can you see the bottom of it? It could be a massive hole under your house, posing a serious threat. Seek professional assistance if the hole appears to be bottomless.

Take note of what you've found upon assessment. Act on the spots that need repairing, if any, like the water pipes or drainpipes. If you're still worried about your safety, leave the rest to the experts.

What Can Happen If The Basement Wall Gap Remains Open?

The situation may worsen if this gap remains unfilled. You should be concerned if there is even a small gap. Keep in mind that the basement is built beneath the ground. As a result, we're going to give you some ideas about what will happen to the basement if the gap isn't closed.

Big wet spots and cracks on the ceiling of the domestic house room after heavy rain and lot of water

The Basement Might Stink

If the gap becomes wet and is left for so long, an unpleasant odor may fill the entire area. It may take some effort to remove the odor because it can adhere to the walls and objects in the basement.

Decrepit basement featuring a soot-covered stairway

A Tree Might Grow

It may sound strange, but it is possible, even if sunlight is absorbed less efficiently inside. A tree can sprout anywhere there is soil, in some cases. When the soil is wet, it occurs more frequently. As a result, a tree is very likely to emerge and destroy the basement floor.

Insects Might Inhabit The Gap

Insects that live beneath the soil might obstruct the gap. It's a real pain if insects take over the rest of the basement. To avoid this nightmare, you should fill the gap.

The Gap Might Become Wider

When moving around the basement, minor vibrations can cause the gap to widen. The gap, like any other wall, has the potential to become a longer crack.

Empty old brightly cracked room

The Floor Will Slope Down

Do not disregard a basement gap. As a result, the floor will begin to slant downward. In addition to widening, the floor may lose its grip on the wall. If there are heavy objects in the basement, such as appliances or excess baggage, this is more likely to happen.

The Entire Area Can Flood

Rainy weather can easily flood the basement if the gap is connected somewhere rainwater can flow. Better look at what's on the other end. If you discover a passageway on the other side, seek expert assistance to bridge the gap.

Water flooded the floor

What Is A Floating Basement Wall?

A floating basement wall will cause the floor to separate and leave a gap along the edge. This is the result of a miscalculation on measurements. It's possible that the wall of the upper ground was made first before finishing the perimeter of the basement. The correct way is to complete the basement first before going up to the higher ground.

In some homes, floating walls were built intentionally. A floating foundation is actually a technique used in construction to lessen the impact of earthquake, soil movements, and improve stability.

Wall and Floor: The Mutual Purpose

Seal the gap and repair the broken points using various methods such as covering the gap, or seeking a professional assistance. Walls and floors, no matter how you fix them, serve the same purpose: to protect. Just remember to have stable ground when facing difficulties.

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