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What Is a Block Foundation Wall?

crew member installing carbon fiber on block foundation wall

If you’re planning to build a home with a basement, your contractor will likely begin with a block foundation. You might be wondering what this is and whether it’s the most durable foundation material.

Read on to discover answers to these and other related questions, along with effective waterproofing methods for repair.

Block Foundation Walls: What Are They? 

concrete block foundation wall

Block foundation walls are constructed by stacking and mortaring blocks called concrete masonry units (CMUs). An initial block layer is built on a concrete footing, and subsequent layers are stacked to reach the desired height.

Standard concrete blocks and compressed stabilized earth blocks are made from materials like limestone or sand mixed with concrete. Regardless of the material, all block foundations require a waterproofing strategy to prevent water leakage, especially in areas with high precipitation.

The History of Block Foundation Walls 

concrete block foundation wall

Block foundations have a relatively recent history in the U.S. compared to traditional materials like brick or stone.

Concrete blocks gained popularity in the early 20th century, marked by Harmon S. Palmer’s 1900 invention of a machine for manufacturing hollow concrete blocks. These lighter, easier-to-transport blocks became practical construction materials. Their affordability and ease of use led to their widespread adoption for foundation walls and below-grade construction.

The Benefits of Block Foundation Walls

Block foundation walls are a popular choice for many reasons. Here are the benefits:

inspector meeting with homeowner on home sidewalk
  • Strength and Durability: Block foundations support substantial weight. They are resistant to fire, termites, and rot, making them a durable foundation choice.
  • Cost-effective: Block foundations are generally less expensive and require less labor than poured concrete due to pre-made blocks and quicker assembly.
  • Ease of Construction: Block foundations are easy to construct, and some have an interlocking capability that requires no curing, saving project time.
  • Versatility: Block foundations are easily stackable and suit various foundation types, including basements, crawl spaces, and slabs.
  • Insulation: Some blocks provide insulation, improving home energy efficiency. Block foundations can also be filled with insulation material for enhanced performance.

Disadvantages of Block Foundation Walls 

person applying epoxy to block foundation wall
  • Leak-prone: If not properly sealed, mortar joints between blocks can allow water infiltration, leading to basement moisture, mold growth, and foundation damage.
  • Less Lateral Strength: Block foundations are less resistant to lateral pressure from soil or water compared to poured concrete, which can cause bowing walls and cracking, especially in high-water table areas.
  • Less Design Flexibility: Block foundations offer less design flexibility due to their modular shape, limiting them to straight walls and basic corners, which may be a drawback.
  • Aesthetics: Exposed block foundations may look less finished, requiring additional covering or treatments if appearance is important.
  • Maintenance: Depending on the size of the cracks, mortar joints may require repointing to maintain waterproofing. Impacts or settling can also damage block foundations.

What Causes Foundation Wall Damage?

Several factors lead to block foundation wall damage. These factors include:

3D image of hydrostatic pressure bowed basement walls

1. Water Infiltration

Moisture and hydrostatic pressure are critical concerns for foundation integrity. Damage occurs in these ways:


Moisture penetration occurs when water seeps through cracks in mortar joints or gaps between blocks, eroding the mortar and weakening the structure. Freeze-thaw cycles worsen this issue.

Hydrostatic Pressure

Poor drainage or high water tables increase the hydrostatic pressure caused by water in the surrounding soil pushing against foundation walls. Standing water and high water tables, particularly near lakes or ponds, can intensify this problem. Over time, hydrostatic pressure allows water infiltration and leaks, attracts pests, and promotes mold growth.

3D image of house and list of Causes of Foundation Settlement

2. Settlement and Pressure

Block foundations, though strong, are susceptible to damage from movement, including:

Foundation Settlement

Foundation settling occurs when the soil beneath the foundation fails to support it properly. This is caused by poor soil compaction or changes in moisture content.

Oversaturated expansive soil softens and causes foundations to sink, while dry soil shrinks, cracks, and fails to provide support. Poorly compacted soil leaves air pockets, compromising structural integrity and allowing foundations to sink into weak soil.

Lateral Pressure

Lateral pressure from soil or water pushing sideways against the foundation walls can also cause bowing or cracking, particularly if the foundation lacks proper reinforcement. Proper drainage around the foundation is crucial to reduce hydrostatic pressure from water accumulation.

How to Repair Foundation Walls 

Foundation wall repair is crucial for protecting your home’s structural integrity and your family’s safety. Here are several ways to repair block foundation walls:

  • Wall Anchors: Address bowing or leaning walls with wall anchors. These reinforcements involve steel plates on both sides connected by a tightening rod that straightens the wall.
  • Carbon Fiber Reinforcement: This method repairs cracks and reinforces block foundations by bonding carbon fiber sheets to the interior or exterior wall surface, providing added strength and preventing further damage.
  • Wall Crack Repair: Monitor hairline cracks less than 1/8 inch and fill them with high-quality sealant if they worsen. Patch larger cracks with hydraulic cement or epoxy to prevent water infiltration and further damage.
  • Foundation Piers: Helical piers, slab piers, and push piers address the foundation settlement that causes wall damage. Foundation piers transfer the structure’s weight to a more stable soil layer.

Addressing bowing walls and cracks before exterior waterproofing is essential. Contact a foundation repair professional for an inspection and tailored solutions for your home.

How to Prevent Block Foundation Wall Damage

Preventing damage before it begins saves time and money long-term. Here are a few ways to prevent wall damage:

crew installing basement waterproofing

Apply Exterior Waterproofing Membrane

High-quality waterproofing membranes applied directly to the exterior foundation walls are crucial. This barrier prevents moisture seepage through the block walls.

Perimeter Drain Tile System

Drain tiles installed around the foundation perimeter collect groundwater and redirect it away from the basement, reducing hydrostatic pressure and preventing water from entering through cracks or gaps.

Backfilling and Compacting

Backfilling and compacting the trench around the foundation after installing drain tiles ensures proper drainage and prevents voids that could collect water.

Basement Waterproofing Methods

Basement waterproofing solutions like vapor barriers, interior drainage systems, sump pumps, and dehumidifiers ensure the area remains dry. This approach prevents the moisture and humidity that cause damage like efflorescence, mold, and rot.

Does Your Home Need Basement Wall Repair?

JES team and two JE branded trucks

Concrete block foundation walls are popular in Virginia, Maryland, and D.C. homes because they are affordable, easy to construct, and durable. If you’ve noticed bowing walls, damp walls, or other damage, contact JES Foundation Repair for a free inspection. We’ve been protecting homes for over 20 years. Let us to safeguard yours.

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    Foundation Wall FAQs

    Not necessarily. However, cracks, especially those that are widening or horizontal, can become entry points for moisture over time. Even if they’re not causing issues now, they might in the future. Regularly inspecting and addressing cracks early can prevent larger problems down the road. Contact JES Foundation Repair for an assessment of any cracks or potential vulnerabilities in your basement.

    Basement Wall Crack

    Have you noticed unsettling cracks weaving across your basement walls? Although foundation cracks are fairly common, they should still be examined rather than dismissed as minor concerns. 

    When left unchecked, these cracks jeopardize your basement’s structural health and can lead to unwanted water intrusion. Fortunately, JES Foundation Repair is here to assist. 

    Our team is equipped to evaluate basement wall cracks, investigate their origins, and suggest trusted, long-term solutions. After reviewing the details on this page, you’ll gain insight into the causes of wall cracks and discover the most effective prevention measures. 

    What Is a Basement Wall Crack? 

    A basement wall crack signifies any break, split, or tear in the material of the basement’s outer framework. These cracks typically emerge when the foundation faces stressors that exploit the weak tensile strength of concrete. 

    Such cracks don’t necessarily indicate a failing foundation. However, they demand timely attention to prevent worsening conditions like water leakage or structural issues. 

    Each crack has unique characteristics – varying in location, nature, pattern, and size, which help determine its severity and the ideal repair method. Our inspection process accurately gauges all visible cracks to offer suitable solutions. 

    What Causes Basement Wall Cracks?  

    Several factors lead to the emergence and progression of basement wall cracks. During an inspection, our team helps you to understand and identify these causes. 

    Soil Movement and Settling 

    Over time, the soil surrounding the basement experiences changes. Sometimes, these shifts result from erosion due to rainfall or groundwater movement. 

    On other occasions, dry spells cause the soil to contract. In both scenarios, the ground fails to support the basement effectively, leading to cracks. 

    Improperly compacted soil can also result in uneven settling and added stress. Such cracks usually run vertically, mirroring the wall’s mortar joints. 

    Hydrostatic Pressure 

    After rain or snow, water accumulates underground, exerting significant lateral pressure. When this occurs adjacent to basement walls, they undergo pressure, leading them to bow or curve, a phenomenon known as hydrostatic pressure. 

    Persistent stress can cause horizontal cracks to form where the water makes contact with the walls. 

    Freeze-Thaw Dynamics 

    Recurring freeze-thaw cycles cause the foundation to expand and contract. When water within the concrete freezes and thaws repeatedly, it results in stress, often leading to vertical cracks, especially at the external wall corners. 

    Improper Curing 

    During its initial curing phase, concrete solidifies and becomes stronger. Problems such as inadequate mixing, premature freezing, excessive water, or improper troweling can result in fragile concrete. This makes it susceptible to cracking under various forces. 

    Poor curing also increases the concrete’s vulnerability to freeze-thaw damage. While homeowners may have little control over this, the problem is solvable. 

    Expanding Tree Roots 

    Growing tree roots can exert pressure on foundations, targeting weak spots in basement walls, especially closer to the perimeter. 

    Accurate diagnosis of the factors causing basement wall cracks will determine the most effective repair strategies. Rest assured, JES Foundation Repair possesses the expertise and tools to combat the forces behind these cracks. 

    Can Cracked Basement Walls Be Repaired? 

    Definitely! With foundation repair technology advancements, replacing entire basement walls due to cracks is no longer necessary. Our experts will reinforce your walls, mend cracks, and ensure they remain robust for years. 

    JES Foundation Repair uses various wall reinforcement techniques to prevent future cracking. Our warrantied solutions promise a safe, stable, and dry basement for years to come. 

    Our Approach to Repairing Cracked Basement Walls 

    JES Foundation Repair’s trusted process has secured countless homes throughout the mid-Atlantic. Our commitment to precision and efficiency sets us apart. Here’s a glimpse of our process: 

    1. Detailed Evaluation 

    Our team methodically maps all present cracks, marking their locations, dimensions, patterns, and openings. This helps identify if soil movement, hydrostatic pressure, tree roots, freeze-thaw cycles, or curing inconsistencies led to the cracks. We also assess the surrounding soil conditions and the foundation’s overall health. 

    2. Setting up Reinforcement Measures 

    JES Foundation Repair installs the ideal reinforcement solutions to strengthen vulnerable areas and prevent further cracks. Options include: 

    3. Integrating Waterproofing and Drainage Solutions 

    We implement an interior drainage system, a dehumidifier, and a robust vapor barrier to combat hydrostatic pressure and prevent moisture seepage through cracks. Our sump pumps efficiently divert water away from the foundation. 

    The Importance of Timely Crack Repairs 

    Delaying repairs can turn minor cracks into major foundational issues. Here’s why swift action is crucial: 

    • Cracks intensify as external forces continue to act, often at an accelerating rate. 
    • Growing cracks invite more water, leading to erosion, potential flooding, and possible mold growth. 
    • Overlooking cracks can cause additional settling, sagging floors, and jeopardize supporting structures. 
    • Repair expenses can surge as cracks spread, not to mention costs from secondary water damage. 
    • For safety reasons, larger foundational cracks might need monitoring sensors in case of rapid expansion. 

    Don’t jeopardize your home’s foundation or your family’s safety. JES Foundation Repair provides prompt, effective solutions to repair existing cracks and strengthen your foundation for enduring stability. We go deeper than surface-level repairs and holistically reinforce basement walls and floors. 

    Choose JES Foundation Repair for Expert Crack Repairs in Virginia and Beyond 

    Cracks in your basement walls or floor slab need attention to avert structural instability and expensive water-related damages.  At JES Foundation Repair, we deploy state-of-the-art solutions to mend existing cracks and fortify your basement.  

    We extend free, thorough basement evaluations, so contact us today to schedule your free inspection! Opt for lasting, holistic solutions, not short-lived fixes – trust JES Foundation Repair to address the root of the issue. 


    Homeowner’s insurance often does not cover basement wall crack repairs unless they result from a specific, covered peril, such as an earthquake or flood. Routine wear and tear or ground movement, which often causes these cracks, is generally not covered.

    Yes, there is a correlation between the age of a home and the likelihood of basement wall cracks. Older homes are generally more susceptible to settling, soil movement, and the cumulative effects of environmental factors, increasing the potential for cracks over time. 

    Differentiating between harmless and potentially dangerous cracks often involves examining their size, direction, and location. Harmless cracks tend to be thin, hairline fractures. In contrast, dangerous cracks can be wider, run horizontally or diagonally, and may be accompanied by wall bowing or other structural changes, indicating deeper foundational issues. 

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    Related Resources

    Foundation wall cracks often signal more than just superficial issues. While some settling is normal, wide cracks that seem to grow are not. At JES Foundation Repair, we’ve built a reputation as Virginia and the surrounding areas’ most reliable foundation repair specialists. 

    What Exactly Are Foundation Wall Cracks? 

    These cracks appear on the concrete walls that support and provide stability to your home. From thin hairline splits to broad openings, these cracks can hint at deeper foundation problems. The size, direction, and width of the crack all tell a story about where the foundation issues are stemming from. Addressing them early with an inspection and tailored repair solutions can save homeowners from more severe issues in the future. 

    Why Do Foundation Wall Cracks Appear? 

    Several factors can lead to the formation of foundation wall cracks: 

    • Settlement: Movement or compression of soil underneath your home can cause the foundation to descend unevenly, resulting in cracks. 
    • Expansive Soils: As they expand or shrink with moisture levels, these soils exert pressure on foundation walls, leading to cracks. 
    • Hydrostatic Pressure: Excessive groundwater can exert force on the foundation walls, causing them to develop cracks or bow inward. 

    Is It Possible to Repair These Cracks? 

    Absolutely! Depending on the nature and extent of the damage, there are various effective methods to restore the foundation’s integrity. At JES, we provide: 

    • Foundation Piers – Installed underneath the foundation and anchored to the foundation footing, piers transfer the weight of the home to stable soils. They stabilize settling foundations and provide support.   
    • Wall Anchors – Steel anchors are embedded into the foundation wall and extended into undisturbed soil. They counteract the inward pressure causing cracks and bowing.  
    • Carbon Fiber Reinforcement – Carbon fiber straps that are up to 10 times stronger than steel are applied to the wall surface to strengthen concrete and prevent cracks from worsening.  
    • IntelliBrace™ Wall Repair System – A network of steel beams is installed inside the wall, providing reinforcement without excavating outdoors. 

    Steps to Mend Foundation Wall Cracks: 

    Our method for repairing your foundation will depend on what we learn in our initial inspection. Through the knowledge we’ve gained over years in the industry, we’ve developed a variety of solutions that we will tailor to your home’s specific needs.  

    1. Professional Evaluation 

    We’ll begin with a comprehensive inspection conducted by a foundation expert who will identify the primary cause and suggest a suitable repair technique as well as a quote and timeline for the repair. 

    2. Install the Foundation Repair System  

    Once we’ve settled on the solution, we’ll implement the tailored foundation repair to target the specific damage encountered in your home.  

    3. Waterproof Walls 

    After strengthening your foundation, it’s essential to make foundation walls water-resistant, preventing future moisture infiltration. 

    4. Regular Checks and Upkeep  

    Our solutions are tailored to be permanent for the issues your foundation experiences. However, periodic evaluations ensure the foundation remains stable. Keep an eye out for new cracks and potential water ingress. 

    Why Address Foundation Wall Cracks Now? 

    Acting promptly on foundation wall cracks is vital: 

    • Ignoring them might lead to bigger, more costly issues. 
    • Water intrusion through cracks can result in mold and impact indoor air quality. 
    • An unsettled foundation can make doors and windows stick or jam
    • Significant cracks can jeopardize your home’s structural safety. 

    Don’t delay! Connect with JES Foundation Repair now. Our specialized solutions reinforce your foundation, mitigating further concerns. We proudly offer free inspections and quotes. 

    Reach Out to JES for Lasting Foundation Wall Crack Solutions 

    With nearly a quarter-century of experience, JES Foundation Repair has consistently assisted homeowners across Virginia and neighboring regions. Our skilled team is equipped to gauge your foundation’s health and offer tailored solutions using advanced techniques and tools. 

    Contact us today for a no-commitment inspection and estimate for foundation repair. Secure your home’s future and enjoy peace of mind with JES’s unmatched expertise. 


    Yearly maintenance is pivotal in ensuring the longevity and stability of the foundation repair work done. During the annual maintenance checks, professionals can spot potential issues early on before they escalate into more serious problems, saving homeowners time and money in the long run.  

    At JES Foundation Repair, we understand your home may change hands several times over its lifetime. The warranty on our repair solution is transferable to a new homeowner. Give us a call and we’ll walk you through the process of getting your warranty transferred when it’s time to sell.  

    Delaying the repair of foundation cracks can lead to a host of problems, including further structural damage, water intrusion leading to mold growth and poor indoor air quality, and even compromised safety of the home. Over time, what might have been a simpler, more cost-effective repair can evolve into a complex, expensive undertaking.  


    Shaye Glisson

    Shaye Glisson

    Shaye is an SEO Content Writer for Groundworks with over twelve years of experience creating helpful content across various industries, including home services and retail. She is a Gulf Coast native and writes from her firsthand knowledge of the area's hurricane and flood impacts on the local community. In her free time, Shaye enjoys exploring the local food and music scenes.

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    JES Foundation Repair service area map of the Mid-Atlantic region.

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