Discovering basement floor cracks can be unsettling. This comprehensive guide helps you understand those cracks, decode their causes, and decide on the best course of action. We’ll cover everything from hairline cracks to more serious issues, so you can approach the situation with confidence and avoid unnecessary stress over basement floor cracks in your concrete basement.
Understanding Basement Floor Cracks
Most concrete basement floors develop cracks over time. This is due to various factors we’ll discuss, such as a sinking concrete slab, or the foundation settling. Don’t worry – most cracks are simply cosmetic and don’t signal structural damage.
It’s crucial to know the differences between crack types. This helps you recognize a real problem versus cosmetic cracking. Knowing the differences lets you prioritize repairs, even in complex scenarios where the floor meet basement walls.
Why Do Basement Floors Crack?
Several culprits cause basement floor cracks. Sometimes the foundation settles, or the concrete shrinks as it cures.
Other times, it’s from soil movement caused by freeze and thaw cycles. Even heavy loads and external forces can cause basement floors to crack. Poor initial construction and concrete shrinkage can also lead to basement cracks, though it is less common.
Hydrostatic Pressure and Drainage
Water is a common enemy of basements. Poorly managed drainage systems amplify this, causing a bigger problem. Hydrostatic pressure builds up against foundation walls and basement floors, worsening cracks.
Improving drainage around your house and basement offers good news for the structural components and basement walls of your house. Doing so protects your concrete slab, floor joists, and the soil beneath from further problems caused by surface cracking.
Consider a sump pump to remove unwanted basement seepage. Improved drainage can also protect you from dangerous soil and soil gasses.
Here’s a checklist for improved drainage:
- Grade landscaping to slope away from the foundation.
- Clean gutters regularly and repair damaged downspouts.
- Extend downspouts further from your house to prevent pooling.
- If your basement waterproofing system is adequate, consider adding a sump pump system to address a crawl space or improve drainage.
Types of Basement Floor Cracks
Not all basement floor cracks are created equal. Here’s how to tell a hairline crack from a heaving crack:
1. Hairline Cracks
These tiny cracks, typically less than ⅛-inch wide, appear as the concrete dries and shrinks. This often happens if temperatures were low during the pouring process.
The technical term is shrinkage. Shrinkage occurs after the basement floor was finished. Hairline cracks are generally cosmetic.
2. Settlement Cracks
These cracks appear when your house settles into the surrounding soil. Because floors are supported by the concrete slab, these cracks are almost never structural.
Settlement cracks tend to be wider than hairline cracks. Seal larger gaps in your basement floor slab to keep out radon gas and pests.
3. Heaving Cracks
These cracks form when the basement floor slab is pushed up from soil swelling. This often occurs when clay soil gets wet and then dries, stressing the concrete slab.
You often see heaving cracks after heavy rains. These cracks suggest underlying foundation movement and a potential foundation problem.
Consult a foundation repair contractor and rule out more serious foundation cracks as early as possible. Uneven concrete or sinking concrete can result if these problems are not addressed.
4. Cracks at the Cove Joint
The cove joint is where the basement floor meets the walls. Cracks here are common and can indicate settlement. Some water seepage here can be normal and not a tripping hazard initially. Seepage can happen especially during rainy periods or winter thaws when the soil beneath your home is wet.
Avoid sealing the cove joint. This prevents identification of later moisture issues. Addressing the root cause, perhaps with a foundation repair contractor, is more beneficial in the long run.
5. Spalling Cracks
These cracks have flaky surfaces and signal weak top concrete layers. They can also indicate incomplete drying, trapping moisture which weakens the concrete over time.
Resurfacing is an option to strengthen your floor and improve its look. This can become important when basement floor cracks begin to bother occupants.
Dealing with Basement Floor Cracks
Crack Type | Action |
---|---|
Hairline | Monitor, no immediate action needed. |
Settlement (less than ⅛-inch) | Monitor and seal if widening. |
Settlement (wider than ⅛-inch) | Seal to keep out moisture, soil gases, pests, and avoid moisture build-up near flooring. |
Heaving | Consult a foundation repair professional. |
Cove Joint | Address any water seepage; do not seal. |
Spalling | Resurface or install flooring. |
When to Worry About Those Basement Floor Cracks
While basement floor cracks are typically benign, pay closer attention if you encounter specific signs. Here’s a checklist of things to be wary of:
- Cracks wider than ⅛-inch: These can allow entry of radon, moisture, and pests.
- Cracks that grow or change: These require a professional foundation evaluation to rule out structural issues.
- One side of the floor noticeably rises above the other: This could suggest a sinking concrete or a sinking concrete slab on the other side. Consider methods to improve drainage or installing a sump pump.
- Wall cracks: These might indicate more significant movement, warranting expert investigation. Such cracks also warrant looking at improper drainage and concrete shrinkage. Cracks appearing as the floor meets a basement wall can be indicative of larger issues and hydrostatic pressure, so a sump pump system and improved drainage is important.
- Moisture coming through cracks: Sealing usually helps, but it’s essential to uncover the cause, perhaps related to hydrostatic pressure or grading around the home’s foundation.
Conclusion
Basement floor cracks are a common problem in concrete basements. Most don’t require significant remediation. Understanding the type of crack helps decide appropriate fixes, like patching. Consulting a foundation repair company for cracks in basement floors and walls is often advisable.
This guide should help avoid unnecessary worry. It offers guidance on proper maintenance for basement floors. This includes not just immediate remedies, but preventing future basement issues. Use your improved knowledge wisely.