As temperatures drop and ground freezing becomes a seasonal reality, homeowners in colder climates must prepare their homes for more than just chilly air and melting snow.
One of the most overlooked but potentially serious winter threats is foundation heaving, which is an upward shift in the concrete foundation or footings caused by the expansion of soil as it freezes. This phenomenon, commonly referred to as frost heave, can damage foundation walls, crack basement floors, warp door frames, and even compromise the structural integrity of a home.
The first step in protecting your home and preventing frost heave is knowing how it happens, which is why we’ve prepared this quick guide where we’ll walk through what causes foundation movement in cold weather, how to spot the warning signs of frost heave, and what preventive steps to take now.
With the right planning—think insulation, crack sealing, and improved waterproofing—homeowners can stop frost heave on their foundation before it begins.
What Is Foundation Heaving?
At the core of foundation heaving is a process known as frost heaving, which occurs when moisture in the ground freezes and expands. When soil conditions are moist or saturated, especially in clay soils common in the San Antonio region, this freezing action creates ice lenses beneath the foundation, lifting slabs, first-floor decks, and masonry structures upward.
Frost heave is often worsened by ice segregation, where water is drawn upward through capillary action and repeatedly freezes near the surface, causing repeated upward shifts.
The issue is further complicated by adfreezing, a process in which frozen soil clings tightly to concrete surfaces, increasing the upward force and making foundation settlement more uneven. These natural processes, when combined with shallow footings, poor insulation layers, or ineffective drainage, create a perfect storm for winter-related foundation damage from frost heave.
Signs of Frost Heave on Foundation
Recognizing foundation heaving early can help minimize long-term structural damage. Here are some of the most common signs:
- Foundation cracks that run vertically or diagonally through walls and slabs
- Uneven or bulging areas in basement floors or garage slabs
- Gaps between walls and floors, particularly in basement or crawl space areas
- Interior doors and windows that stick or become misaligned during winter
- Recurring winter basement cracks after freeze-thaw periods
- Movement or cracking in driveways, sidewalks, or patios connected to the home’s structure
Many of these issues start subtly but become more noticeable as freeze-thaw cycles continue throughout the season. Monitoring and addressing them before the next deep freeze is vital.
Key Triggers for Foundation Frost Heave During Cold Weather
When cold temperatures set in, the soil around and beneath your home doesn’t just harden—it expands. If the soil has a high moisture content, freezing temperatures can cause a significant increase in volume. This expansion exerts pressure on the foundation walls, footings, and even interior supports.
Moisture Is the Key Trigger
Frost heaving is far more likely when moisture is present in the soil. Stormwater runoff, leaking pipes, or poor drainage systems can saturate the ground before a freeze, turning your yard into a hidden hazard. When this water turns to ice, it lifts the foundation upward—and as the ground freezes and thaws repeatedly, the damage can worsen.
If downspouts and gutters are clogged or misdirected, they may deposit melting snow and ice melt directly against your concrete foundation. Without proper French drains or frost sleeves, that water has nowhere to go but down, into the soil beneath your home, and then trigger frost heave during the next freeze.
Soil Type and Structural Conditions Matter
Homes built on clay soils are at higher risk of frost heaving due to the soil’s ability to retain water. Combine that with shallow foundation footings, lack of rigid EPS foam insulation, or no Frost Protected Shallow Foundation (FPSF) systems, and you’ve got a recipe for movement.
Additionally, homes without proper insulation around basement walls or crawl space supports may also experience faster heat loss, contributing to frozen ground and increased heating bills. Improperly insulated homes are not only vulnerable to frost heaving but also suffer in terms of air quality and energy efficiency.
Proactive Steps to Prevent Foundation Heaving
Preventing foundation heaving in cold weather requires a multi-pronged approach that addresses soil moisture, drainage, insulation, and structural vulnerabilities. The sooner these strategies are implemented (ideally before the first hard freeze), the more effectively homeowners can guard against movement and damage to their foundation.
Improve Drainage Around the Home
Water is the root cause of most cold-weather foundation issues. A poorly functioning drainage system allows water to collect near the home’s perimeter, where it can saturate the soil and later freeze.
Key Tips:
- Install or maintain French drains to reduce water saturation around the foundation.
- Add gravel-filled trenches near footings to improve runoff.
- Inspect sump pump systems seasonally to ensure they’re ready for freeze conditions. Doubly important in older homes or areas with high water tables.
- Check discharge lines for clogs or freezing risk.
Keep Gutters and Downspouts Clear
Clogged gutters and disconnected downspouts can dump runoff directly along the foundation.
Key Tips:
- Clear all leaves and debris from gutters before the first frost.
- Extend downspouts to discharge water at least six feet away from the home or structure.
- Inspect joints and brackets to prevent leaks near the foundation.
- Consider installing gutter guards for long-term maintenance ease.
Insulate Around the Foundation
Installing rigid EPS foam insulation, rigid-foam insulation, or even mineral wool around foundation walls and slab edges helps reduce frost penetration into the soil. This is especially important for homes with shallow footings or exposed basement walls, which are among the most susceptible to frost heave.
For new builds or major renovations, a Frost Protected Shallow Foundation system can be a long-term solution that incorporates both insulation and soil management.
In crawl spaces, insulating walls and rim joists helps prevent heat loss and reduces the chances of the ground freezing underneath, which could otherwise cause shifting in crawl space supports.
Key Benefits:
- Prevents frost from reaching the soil beneath the foundation.
- Reduces heat loss and heating bills in winter.
- Helps stabilize temperatures in crawl spaces and basements.
- Minimizes risk of frost heaving in shallow foundations.
Address Soil Grading and Landscaping
The slope of the land around your home plays a major role in how stormwater runoff behaves. If the grade directs water toward the foundation rather than away, it will increase the risk of saturation and heaving.
Key Tips:
- Regrade soil to slope at least 6 inches over 10 feet away from the foundation on all sides.
- Avoid bark mulch or other materials that trap moisture near foundation walls.
- Keep landscaping at least 3–5 feet from the structure’s edge and avoid planting water-loving trees or shrubs too close to the foundation. Their root systems can alter soil conditions and increase the risk of foundation movement during freezes.
- Use gravel beds to increase evaporation and control runoff.
Seal Cracks and Gaps Before Winter
Even small openings in the foundation or surrounding concrete surfaces can allow water leaks to penetrate and freeze, expanding inside the crack and making it worse.
Key Tips:
- Use flexible sealants or epoxy to allow for winter expansion and contraction.
- Apply professional-grade crack sealing to visible foundation cracks, slab joints, and gaps, especially around windows, vents, and pipe penetrations.
- Don’t overlook cracks in sidewalks, patios, or driveways connected to the home.
- For older homes, consider a full waterproofing membrane or coating if leaks are recurring.
When to Call a Foundation Repair Professional
Even with the best planning, foundation movement can still occur, especially in areas with unpredictable winters or poorly draining soil. When signs of frost heaving appear, homeowners need to consult a qualified foundation repair expert before minor problems escalate into major structural concerns.
Red Flags That Warrant a Professional Inspection
If any of the following conditions are present, it’s time to schedule an inspection:
- New or worsening foundation cracks, all in winter
- Uneven floors, sticking doors, or bowing foundation walls
- Water intrusion or moisture problems in the basement or crawl space
- Unusual movement in sidewalks, driveways, or patio slabs
- Evidence of heaving, such as raised slab sections or exposed footing edges
A trained professional can perform soil testing, inspect insulation and drainage systems, and evaluate the extent of frost-related movement. Depending on what they find, they may recommend repairs such as helical piers, crawl space supports, wall stabilization, or structural reinforcement with carbon fiber straps or steel posts.
Benefits of Early Intervention
Calling in a specialist early, ideally before the deep freeze, can:
- Help identify and fix moisture problems before the ground freezes
- Prevent minor structural movement from becoming major damage
- Extend the life of your concrete foundation and connected structures
- Provide peace of mind through documented evaluations and repair options
Protect Your Foundation Before the Freeze
Frost heaving is a preventable winter threat, but only if homeowners take proactive steps before the temperature drops. From improving drainage and sealing cracks to adding insulation and managing soil grading, every measure helps reduce the risk of soil expansion and foundation movement during freeze-thaw cycles.
Don’t wait for visible damage to occur. If you’re noticing early signs of foundation stress from frost heave, or just want to prepare your property for winter, contact Xpert Foundation Repair today.
Our team provides expert inspections, seasonal readiness assessments, and long-term solutions to keep your home safe, dry, and structurally sound—no matter how cold it gets.
